Several spinning factories with important English machinery have been established during the last twenty years, but Consul Longford says that he has only known of one similar cotton-weaving factory, and that has not been a successful experiment. Other so called weaving factories throughout the country consist only of a collection of the ordinary hand looms, to the number of forty or fifty, scarcely ever reaching to one hundred, in one building or shed, wherein individual manufacturers have their own special piece goods made.

The first operation in the manufacture is that of ginning, which is conducted by means of a small implement called the rokuro, or windlass. This consists of two wooden rollers revolving in opposite directions, fixed on a frame about 12 inches high and 6 inches in width, standing on a small platform, the dimensions of which slightly exceed that of the frame. The operator, usually a woman, kneels on one side of the frame, holding it firm by her weight, works the roller with one hand, and with the other presses the cotton, which she takes from a heap at her side, between the rollers. The cotton passes through, falling in small lumps on the other side of the frame, while the seeds fall on that nearest the woman. The utmost weight of unginned cotton that one woman working an entire day of ten hours can give is from 8 lb. to 10 lb., which gives, in the end, only a little over 3 lb. weight of ginned cotton, and her daily earnings amount to less than 2d. A few saw gins have been introduced into Japan during the last fifteen years, but no effort has been made to secure their distribution throughout the country districts. After ginning, a certain proportion of the seed is reserved for the agricultural requirements of the following year, and the remainder is sent to oil factories, where it is pressed, and yields about one-eighth of its capacity in measurement in oil, the refuse, after pressing, being used for manure. The ginning having been finished in the country districts, the cotton is either packed in bales and sent to the dealers in the cities, or else the next process, that of carding, is at once proceeded with on the spot.

This process is almost as primitive as that of the ginning. A long bamboo, sufficiently thin to be flexible, is fastened at its base to a pillar or the corner of a small room. It slopes upward into the center of the room, and from its upper end a hempen cord is suspended. To this is fastened the "bow," an instrument made of oak, about five feet in length, two inches in circumference, and shaped like a ladle. A string of coarse catgut is tightly stretched from end to end of the bow, and this is beaten with a small mallet made of willow, bound at the end with a ring of iron or brass. The raw cotton, in its coarse state, is piled on the floor just underneath the string of the bow. The string is then rapidly beaten with the mallet, and as it rises and falls it catches the rough cotton, cuts it to the required degree of fineness, removes impurities from it, and flings it to the side of the operator, where it falls on a hempen net stretched over a four-cornered wooden frame. The spaces of the net are about one-quarter of an inch square, and through these any particles of dust that may still have adhered to the cotton fall to the floor, leaving piled on top of the net the pure cotton wool in its finished state. This work is always performed by a man, and by assiduous toil throughout a long day, one man can card from ten to twenty pounds weight of raw cotton. Payment is made in proportion to the work done, and in the less remote country districts is at the rate of about one penny for each pound carded. As regards spinning and weaving, in the first of these branches of cotton manufacture the Japanese have largely had recourse to the aid of foreign machinery, but it is still to a much greater extent a domestic industry, or at best carried on like weaving in the establishments of cotton traders, in which a number of workers, varying from 20 to 100 or more, each with his own spinning wheel, are collected together. Consul Longford says the spinning wheel used in Japan differs in no respect from that used in the country 300 years ago or (except that bamboo forms an integral part of the materials of which it is made) from that used in England prior to the invention of the jenny. The cost of one of the wheels is about 9d., it will last for five or six years, and with it a woman of ordinary skill can spin about 1 lb. of yarn in a day of ten hours, earning thereby about 2d. There are at present in various parts of Japan, in all, 21 spinning factories worked by foreign machinery. Of four of these there is no information, but of the remainder, one has 120 spindles; eleven, 2,000 spindles; two, 3,000 spindles; two, 4,000 spindles; and one, 18,000 spindles.—Journal Soc. of Arts.

* * * * *

[Continued from SUPPLEMENT, No. 612, page 9774.]



CENTRIFUGAL EXTRACTORS.

By ROBERT F. GIBSON.

SUGAR MACHINES.—Besides separating the crystalline sugar and the sirup, secondary objects are to wash the crystals and to pack them in cakes. The cleansing fluid or "white liquor" is introduced at the center of the basket and is hurled against and passes through the sugar wall left from draining. The basket may be divided into compartments and the liquor guided into each. The compartments are removable boxes and are shaped to give bars or cakes or any form desired of sugar in mass. These boxes being removable cannot fit tightly against the liquor guides, and the liquor is apt to escape. This difficulty is overcome by giving the guides radial movement or by having rubber packing around the edges.

Sugar machines proper are of two kinds—those which are loaded, drained and then unloaded and those which are continuous in their working. The various figures preceding are of the first kind, and what has been said of vibrations applies directly to these.

The general advantages claimed for continuous working over intermittent are—that saving is made of time and motive power incident to introducing charge and developing velocity, in retarding and stopping, and in discharging; that, as the power is brought into the machine continuously, no shifting of belts or ungearing is necessary; and that there are less of the dangers incident to variable motion, either in the machine itself or the belting or gearing. The magma (the mixture of crystalline sugar and sirup) is fed in gradually, by which means it is more likely to assume a position of equilibrium in the basket.

There are two methods of discharging in continuous working—the sugar is thrown out periodically as the basket fills, or continuously. In neither case is the speed slackened. In the first either the upper half of the basket has an upward motion, on the lower half a downward motion (Pat. 252,483); and through the opening thus made the sugar is thrown. Fig. 22 (R.B. Palmer & Sons) is a machine of this kind. The bottom, B, with the cone distributor, a, have downward motion.



Continuous discharge of the second kind may be brought about by having a scoop fixed to the curb (or casing), extending down into the basket and delivering the sugar over the side (Pat. 144,319). Another method will be described under "Beet Machines."

BASKET.—The construction of the basket is exceedingly important. Hard experience has taught this. When centrifugals were first introduced, users were compelled by law to put them below ground; for they frequently exploded, owing to the speed being suddenly augmented by inequalities in the running of the engine or to the basket being too weak to resist the centrifugal force of the overcharge. Increasing the thickness merely adds to the centrifugal force, and hence to the danger, as even a perfectly balanced basket may sever.

One plan for a better basket was to have more than one wall. For example, there might be an inner wall of perforated copper, then one of wire gauze, and then another of copper with larger perforations. Another plan was to have an internal metallic cloth, bearing against the internally projecting ridges of the corrugations of the basket wall. A further complication is to give this internal gauze cylinder a rotation relative to the basket.

The basket wall has been variously constructed. In one case it consists of wire wound round and round and fastened to uprights, commonly known as the "wire basket;" in another case of a periphery without perforations, but spirally corrugated and having an opening at the bottom for the escape of the extracted liquid; in still another of a series of narrow bars or rings, placed edgewise, packed as close as desired. An advantage of this last style is that it is easily cleaned.

The best basket consists of sheet metal with bored perforations and having bands or flanges sprung on around the outside. The metal is brass, if it is apt to be corroded; if not, sheet iron. The perforations may be round, or horizontally much longer than wide vertically. One method for the manufacture of the basket wall (Pat. 149,553) is to roll down a plate, having round perforations, to the required thickness, causing narrowing and elongation of the holes and at the same time hardening the plate by compacting its texture. Long narrow slots are well adapted to catch sugar crystals, and this is not an unimportant point. Round perforations are usually countersunk. Instead of flanges, wire bands have been used, their lapping ends secured by solder.

As to comparative wear, it maybe remarked that one perforated basket will outlast three wire ones.

As to size, sugar baskets vary from 80 inches in diameter by 14 in. depth to 54 by 24. They are made, however, in England as large as 6 feet in diameter—a size which can be run only at a comparatively slow speed.

A peculiar complication of basket deserves notice (Pat. 275 874). It had been noticed that when a charge of magma was put into a centrifugal in one mass, the sugar wall on the side of the basket was apt to form irregularly, too thick at base and of varied color. To remedy this it was suggested to have within and concentric with the basket a charger with flaring sides, into which the mixture was to be put. When this charger reached a certain rotary velocity, the magma would be hurled out over the edge by centrifugal force and evenly distributed on the wall of the main basket.

SPINDLE.—The spindle as now made is solid cast steel, and the considerations governing its size, form, material, etc., are identical with those for any spindle. In order that the basket might be replaced by another after draining, the shaft has been made telescopic, but at the expense of stability and rigidity. In Fig. 16 is shown a device to avoid crystallizations, which are apt to occur in large forgings, and would prove fatal should they creep into the upper part of the spindle proper in a hanging machine. It consists of the secondary spindle, c.

DISCHARGING.—The drained sugar may either be lifted over the top of the basket (in machines which stop to be emptied), or be cast through openings in the bottom provided with valves. A section of the best form of valve may be seen in Figs. 15 and 17. Fig. 23 is a plan of the openings. The valve turns on the basket bearing. It may be constructed to open in the same direction in which the basket turns; so that when the brake is put on, the inertia of the valve operates to open it and while running to keep it closed. There are many other styles, but no other need be mentioned.



CASING.—The different styles of casing may be seen by reference to the various drawings. In one machine (not described) the casing is rigidly fixed to the basket, space enough being left between the bottom of the basket and the bottom of the casing to hold all the molasses from a charge. This arrangement merely adds to the bulk of the revolving parts, and no real advantage is gained.

BEARINGS.—The various styles of bearings can be seen by reference to the figures. One which deserves special attention is shown in Fig. 16 and Fig. 19. In one case it consists of loose disks, in the other of loose washers, rotating on one another. They are alternately of steel and hard bronze (copper and tin).

"There is probably no machine so little understood or so imperfectly constructed by the common manufacturer of sugar supplies as the high speed separator or centrifugal." Unless the product of experience and good workmanship, it is a dangerous thing at high velocities. Besides, its usual fate is to have an incompetent workman assigned to it, who does not use judgment in charging and running. So that designers and manufacturers have been forced not only to take into account the disturbing forces inherent in revolving bodies, but also to make allowance for poor management in running and neglect in cleaning.

CANE AND BEET MACHINES.—The first step in the process of sugar making is the extraction of the juice from the beet or cane. This juice is obtained by pressure. The operation is not usually, but may be, performed in a special kind of centrifugal. One style (Pat. 239,222) consists of a conical basket with a spiral flange within on the shaft, and turning on the shaft, and having a slight rotary motion relative to the basket. The material is fed in and moves downward under increased pressure, the sirup released flying out through the perforations of the basket, the whole revolving at high velocity. The solid portion falls out at the bottom. Another plan suggested (Pat. 343,932) is to let a loose cover of an ordinary cylindrical basket screw itself down into the basket, by reason of its slower velocity (owing to inertia), causing pressure on the charge.

Various other applications of the different styles of sugar machines are the defibration of raw sugar juice, freeing beet crystals of objectionable salts, freeing various crystals of the mother liquor, drying saltpeter.

DRIERS.—Another important division of this first class of centrifugals is that of driers or, as they are variously styled, whizzers, wringers, hydro-extractors. The charge in these is never large in weight compared to a sugar charge, and its initial distribution can be made more symmetrical. The uses of driers are various, such as extracting water from clothes, cloth, silk, yarns, etc. Water may be introduced at the center of the basket from above or below to wash the material before draining. A typical form of drier is shown in Fig. 24. (Pat. Aug. 22, 1876—W.P. Uhlinger.) Baskets have been made removable for use in dyeing establishments, basket and load together going into dyeing vat. Yarn and similar material can be drained by a method analogous to that of hanging it upon sticks in a room and allowing the water to drip off. It is suspended from short sticks, which are held in horizontal layers around the shaft in the basket, and the action is such during the operation as to cause the yarn to stand out in radial lines.



Driers are not materially different from sugar machines. Any of the devices before enumerated for meeting vibrations in the latter may be applied to the former. There is one curious invention which has been applied to driers only (Pat. 322,762—W.H. Tolhurst). See Fig. 25. A convex shaft-supporting step resting on a concave supporting base, with the center of its arc of concavity at the center of the upper universal joint, has been employed, and its movements controlled by springs, but the step was apt to be forced from its support. The drawing shows the improvement on this, which is to give the shaft-supporting step a less radius of curvature.



An interesting form of drier has its own motor, a little steam engine, attached to the frame of the machine. See Fig 24. This of course demands fixed bearings. The engine is very small. One size used is 3"x4". When a higher velocity of basket is required, we have the arrangement in Fig. 26.



MOTORS.—This naturally introduces the subject of motive power. We may have the engine direct acting as above, or the power may be brought on by belting. Fig. 27 shows a drier with pulley for belting. Fig. 28 (W.H. Tolhurst) shows a very common arrangement of belting and also the fast and loose pulleys. When the heaviest part of the engine is so far from the vertical shaft as to overhang the casing on one side, there is apt to be an objectionable tremor. To remedy this, it is suggested to put these heavy parts as near the shaft as possible. It has been suggested also to use the Westinghouse type of engine, although the type shown in Fig. 24 works faultlessly in practice.



One plan (Pat. 346,030), designed to combine the advantages of a direct acting motor and an oscillating shaft, mounts the whole machine, motor and all, on a rocking frame. The spindle is of course in fixed bearings in the frame. However, the plan is not practical.



In driers the direct acting engine has many advantages over the belt. The atmosphere is always very moist about a whizzer, and there are frequently injurious fumes. The belt will be alternately dry and wet, stretched and limp, and wears out rapidly and is liable to sever. In all machines in which the shaft oscillates, if the center of oscillation does not lie in the central plane of the belt, the tension of the latter is not uniform. This affects badly both the belt and the running. A reference to the various figures will show the best position for the pulley.

The greatest difficulty experienced with belting is in getting up speed and stopping. The basket must not be started with a sudden impulse. Its inertia will resist and something must give way. A gradual starting can be obtained by the slipping of the belt at first, but this is expensive. The best plan is to conduct the power through a species of friction clutch—an iron disk between two wooden ones. This has been found to work admirably.

BRAKES.—The first centrifugals had no brakes. They ran until the friction of the bearings was sufficient to stop them. This occasioned, however, rapid wearing and too great a loss of time. The best material for a brake consists of soft wood into which shoe pegs have been driven, and which is thoroughly saturated with oil. The wooden disks referred to just above are of the same construction. The center of oscillation ought to be in the central plane of the brake as well as that of the pulley, but the preference is given to the pulley.

Figs. 15 and 16 (I) give sectional views of a brake for hanging machines. Figs. 19, 20, and 21 give two sections and a view of a brake which can be used on both hanging and standing machines. A very simple form of brake is shown in Figs. 24, 26, and 27 (A), a mere block pressing on the rim of the basket.

OIL AND FAT.—A machine in most respects like a whizzer is used for the "extraction of oil and fat and oily and fatty matters from woolen yarns and fabrics, and such other fibrous material or mixtures of materials as are from their nature affected in color or quality when hydrocarbons are used for the purpose of extracting such oily or fatty matters, and are subsequently removed from the material under treatment by the slow process of admitting steam, or using other means of raising the temperature to the respective boiling points of such hydrocarbons, and so driving them off by evaporation." In the centrifugal method carbon-bisulphide, or some other volatile agent, is admitted and is driven through the material by centrifugal force, when the necessary reactions take place, and is allowed to escape in the form of hydrocarbons. A machine differing only in slight particulars from the above is used for cleansing wool.

LOOSE FIBER.—Another application is the drying of loose fiber. Two distinctive points deserve to be noticed in the centrifugal used for this purpose. An endless chain or belt provided with blades moves the material vertically in the basket, and discharges it over the edge. During its upward course the material is subjected to a shower of water to wash it.

OIL FROM METAL CHIPS.—Very material savings are made in many factories by collecting the metal chips and turnings, coated and mixed with oil, which fall from the various machines, and extracting the oil centrifugally. The separator consists of a chip holder, having an imperforate shell flaring upward and outward from the spindle (in fixed bearings) to which it is attached. When filled, a cover is placed upon it and keyed to the spindle. Between the cover and holder there is a small annular opening through which oil, but not chips, can escape. Fig. 29 (Pat. 225,949—C.F. Roper) is designed (like the greater part of the drawings inserted) to show relative position of parts merely, and not relative size. This style of machine can be used for sugar separating (Pat. 345,994—F.P. Sherman) and many other purposes, to which, however, there are other styles more especially adapted.



FILTERERS.—There are two distinct kinds of centrifugal filterers, working on different principles. Petroleum separators (Pat. 217,063) are of the first kind. They are in form in all respects like a sugar machine. The flakes of paraffine, stearine, etc., which are to be extracted, when chilled are very brittle and would be disintegrated upon being hurled against a plain wire gauze and would escape. Even a woven fabric presents too harsh a surface. It is necessary to have a very elastic basket lining of wool, cotton, or other fibrous material. The basket itself may be either wire or perforated, but must have a perfectly smooth bottom.

As the pressure of the liquor upon the filtering medium per unit of surface depends entirely upon its radial depth, mere tubes, connecting a central inlet with an annular compartment, will serve the purpose quite as well as a whole basket. In this style of machine (Pat. 10,457) the filtering material constitutes a wall between two annular compartments. The outer one is connected with a vacuum apparatus.

Filterers of the second kind work on the following principle: If a cylinder be rapidly revolved in a liquid in which solid particles are suspended, the liquid will be drawn into a like rotation and the heavy particles will be thrown to the outer part of the receptacle. If a perforated cylinder is used as stirrer, the purified liquid will escape into it through the perforations and may be conducted away. The impurities, likewise, after falling down the sides of the receptacle, are carried off. The advantages of this method are that no filtering material is needed and the filtering surface is never in contact with anything but pure liquor.

Very fine sawdust is, to a considerable extent, employed in sugar refineries as a filtering medium. By such use the sawdust becomes mixed with sand, fine particles of cane, etc. As sawdust of such fineness is expensive, it is desirable to purify it in order to reuse it. A centrifugal (Pat. 353,775—J.V.V. Booraem) built on the following principle is used for this purpose. It has been observed that by rotating rather slowly small particles of various substances in water, the finer particles will be thrown outward and deposit near the circumference of the vessel, while the heavier and coarser particles will deposit nearer to or at the center, their centrifugal force not being sufficient to carry them out. A mere rod, extending radially in both directions, serves by its rotation to set the water in motion.

Another form of filter of this second kind (Pat. 148,513) has a rotating imperforate basket into which the impure liquor is run. Within and concentric with it is another cylinder whose walls are of some filtering medium. The liquid already partly purified by centrifugal force passes through into the inner cylinder, thus becoming further purified. Centrifugal filters are used also to cleanse gums for varnishes.

HONEY.—The simplest form of honey extractor (Pat. 61,216) consists of a square framework, symmetrical with respect to a vertical spindle. This framework is surrounded by a wire gauze. The combs, after having the heads of the cells cut off, are placed in comb-holders against the wire netting on the four sides, the cells pointing outward. The machine is turned by hand. The honey is hurled against the walls of a receiving case and caught below. But few improvements have been made on this. The latest machines are still hand-driven, as a sufficiently high velocity can be obtained in this manner. In one style the combs are placed upon a floor which rests upon springs. The rotating box is given a slight vertical and horizontal reciprocatory motion, by which the combs are made to grate on the wire gauze sides, breaking the cells and liberating the honey. Thus the labor of cutting the cells is saved. Every comb has two sides, and to present each side in succession to the outside without removing from the basket, several devices have been patented. In some the comb holders are hinged in the corners of the basket, and have an angular motion of ninety degrees. Decreasing the speed is sufficient to swing these. The other side is then emptied by revolving in the opposite direction. In one case each holder has a spindle of its own, connected with the main spindle by gearing and, to present opposite side, turns through 180 deg.. The usual number of sides and hence of comb holders is four, but eight have been used. There are minor differences in details of construction, looking to the most convenient removal and insertion of comb, the reception of the extracted honey in cups, buckets, etc., and the best method of giving rapid rotation, which cannot be touched upon. The product of the operation is white and opaque, but upon heating regains its golden color and transparency.

STARCH.—A centrifugal to separate starch from triturated grain, carried in suspension in water, is as follows. (Pat. 273,127—Mueller & Decastro.) The starch water is led to the bottom of a basket, and, as starch is heavier than the gluten with which it is mixed, the former will be immediately compacted against the periphery of the basket, lodging first in the lower corner, the starch and gluten forming two distinct strata. A tube with a cutting edge enters the compacted mass so deeply as to peel off the gluten and part of the starch, which is carried through the tube to another compartment of the basket, just above, where the same operation is performed, and so on. There may be only one compartment, the tube carrying the gluten directly out of the machine. These machines are continuous working, and hence some way must be devised to carry the water off. The inner surface of the water is, as we have seen, a cylinder. When the diameter of this cylinder becomes too small, overflow must be allowed. One plan is to have an overflow opening made in the bottom of the basket in such a way that as the starch wall thickens, the opening recedes toward the center. The starch wall is either lifted out in cakes or put again in suspension by spraying water on it and conducting the mixture off.

A centrifugal (Pat. 74,021) to separate liquids from paints depends on building a wall of paint on the sides of the basket and carrying the liquids off at the center.

A centrifugal (Pat. 310,469) for assorting wood pulp, paper pulp, etc., works by massing the constituents in two or three cylindrical strata, and after action severing and removing these separately.

BREWING.—In brewing, centrifugals are quite useful. After the wort has been boiled with hops, albuminous matters are precipitated by the tannic acid, which must be extracted. Besides these the mixture frequently contains husk, fiber, and gluten. The machine (Pat. 315,876), although quite unique in construction, has the same principle of working as a sugar centrifugal, and need not be described. There is one point, however, which might be noticed—that air is introduced at about the same point as the material, and has an oxidizing and refrigerating effect.

Class I. includes also centrifugals for the following purposes: The removal of must from the grape after crushing, making butter, extracting oils from solid fats, separating the liquid and solid parts of sewerage, drying hides, skins, spent tan and the like, drying coils of wire.

HORIZONTAL CENTRIFUGALS.—Only vertical machines have been and will be dealt with. Horizontal centrifugals, that is, those whose spindles are horizontal have been made, but the great inconvenience of charging and discharging connected with them has occasioned their disuse; though in other respects for liquids they are quite as good as vertical separators. Their underlying theory is practically the same as that hereinbefore discussed.

CLASS II., CREAMERS.—Centrifugals of the second class separate liquids from liquids. There are two main applications in this class—to separate cream from milk and fusel oil from alcoholic liquors. When a liquid is to be separated from a liquid, the receptacle must be imperforate. The components of different specific gravity become arranged in distinct concentric cylindrical strata in the basket, and must be conducted away separately. In creamers the particles of cream must not be broken or subjected to any concussion, as partial churning is caused and the cream will, in consequence, sour more rapidly.

The chief cause of oscillations in machines of this class, where the charge is liquid, is the waves which form on the inner surface. They may be met by allowing a slight overflow over the inner edge of the rim of the basket; or by having either horizontal partitions, or vertical, radial ones, special cases of which will be noticed. Oscillations may also be met in the same manner as in sugar machines, by allowing the revolving parts to revolve about an axis through their common center of gravity. (Pat. 360,342—J. Evans.)

The crudest form of creamer contains a number of bottles, with their necks all directed toward the spindle, filled with milk. The necks, in which the cream collects, are graduated to tell when the operation is complete.

Many methods for introducing the milk into creamers have been devised. It may run in from the top at the center, or emerge from a pipe at the bottom of the basket; or the spindle may be hollow and the milk sucked up through it from a basin below. It is usual to let the milk enter under hydrostatic pressure (Pat. 239,900—D. M. Weston) and let the force of expulsion of the cream be dependent on this pressure. This renders the escape quiet, and prevents churning. Gravity, too, is made effective in carrying the constituents off.

The cream may escape through a passage in the bottom at the center, and the skim milk at the lower outer corner; or by ingeniously managed passages both may escape at or near center. The rate of discharge can be managed by regulating the size of opening of exit passages.

A curious method consists in having discharge pipes provided with valves and floats at their lower ends, dipping into the liquid (Pat. 240,175). "The valves are opened and closed, or partially opened or closed, by the floats attached to them, these floats being so constructed and arranged with reference to their specific gravity and the specific gravity of the component parts of the liquids operated upon, that they will permit only a liquid of a determinate specific gravity to escape through the pipes to which they are respectively attached."

We may have tubes directed into the different strata with cutting edges. (Pat. 288,782.) A remarkable fact noticed in their use is that these edges wear as rapidly as if solids were cut instead of liquids.

The separated fluids may be received into recessed rings, having discharge pipes, the proportionate quantity discharged being regulated by the proximity of the discharge lips to the surface of the ring, and the centrifugal force being availed of to project the liquids through the discharge pipes.

There is a very simple device by which a very rapid circulation of the liquid is brought about. (Pat. 358,587—C.A. Backstrom.) The basket has radial vertical partitions, all but one having communicating holes, alternately in upper and lower corners. The milk is delivered into the basket on one side of this imperforate partition and must travel the whole circuit of the basket through these communicating holes, until it reaches the partition again, and then passes into a discharge pipe. Thus during this long course every particle of cream escapes to the center. As the holes are close to the walls of the basket, the cream has not the undulatory motion of the milk, which would injure it. The greater the number of partitions, the longer is the travel of the milk, and the more rapid the circulation. Blades have been devised similar to the above, having communicating passages extending the whole width of the blade, but we see that here the cream would circulate with the milk; which must not be allowed. Curved blades have been used, and paddles and stirrers, to set the milk in motion, but to them the same objection may be made.



Fig. 30 (Pat. 355,048—C.A. Backstrom) illustrates one of the latest and best styles of creamers. The milk enters at C. The skim milk passes into tube, T, and the cream goes to the center and passes out of the openings in the bottom, k^{l}, k^{2}, and k^{3}, out of the slit, k, and thence out through D^{5}. The skim milk moves through T, becoming more thoroughly separated all the while, and at each of the radial branch tubes, T^{1}, T^{2}, T^{3}, and T^{4}, some cream leaves it and goes to the center, while it passes down out of slit, t^{3}, and thence out of D^{6}.

Fig. 31 (Pat. 355,050—C.A. Backstrom) shows another very late style of creamer. A pipe delivers the milk into P^{4}. Passing out of the tube separation takes place, and cream falls down the center to P^{2} and out of O^{3}. When the compartment under the first shelf becomes full of the skim milk, the latter passes up through the slot, S, strikes a radial partition, R, and its course is reversed. Here more cream separates and passes to center and falls directly, and so on through the whole series of annular compartments, until the top one, when the skim milk enters tube T^{2} and passes out of O^{2}. By this operation there are substantially repeated subjections of specified quantities of milk to the action of centrifugal force, bringing about a thorough separation. By changing the course of the milk in direction, its path is made longer. This machine can run at much lower speed than many other styles, and yet do the same work.



CLASS III., SOLIDS FROM SOLIDS.—As for grain machines, which are in this class, it may be said that in centrifugal flour bolters, bran cleaners, and middlings purifiers, though theoretically centrifugal force plays an important part in their action, yet practically the real separation is brought about by other agencies: in some by brushes which rub the finer particles through wire netting as they rotate against it.

The principle exhibited in a separator of grains and seeds is very neat. (Pat. 167,297.) See Fig. 32. That part of the machine with which we have to do consists essentially of a horizontal revolving disk. The mixed grains are cast on this disk, pass to the edge, and are hurled off at a tangent. Suppose at A. Each particle is immediately acted on by three forces. For all particles of the same size and having the same velocity the resistance of the air may be taken the same, that is, proportional to the area presented. The acceleration of gravity is the same; but the inertia of the heavier grain is greater. The resultant of the two conspiring forces R and (Mv^{2})/2 varies, and is greater for a heavier grain. Therefore, the paths described in the air will vary, especially in length; and how this is utilized the drawing illustrates.



ORE.—In ore machines there is one for pulverizing and separating coal (Pat. 306,544), in which there is a breaker provided with helical blades or paddles, partaking of rapid rotary motion within a stationary cylinder of wire netting. The dust, constituting the valuable part of the product, is hurled out as fast as formed. In this style of machine, beaters are necessary not only for pulverizing, but to get up rotary motion for generating centrifugal force. In the classes preceding, the friction of the basket sufficed for this latter purpose; but here there is no rotating basket and no definite charge. As the material falls through the machine, separation takes place. Various kinds of ore may be treated in the same manner.

An "ore concentrator" (Pat. 254,123), as it is called, consists of a pan having rotary and oscillatory motions. Crushed ore is delivered over the edge in water. The heavy particles of the metal are thrown by centrifugal force against the rim of the pan, overcoming the force of the water, which carries the sand and other impurities in toward the center and away.

AMALGAMATORS.—The best ore centrifugal or separator is what is called an "amalgamator." The last invention (Pat. 355,958, White) consists essentially of a pan, a meridian section of which would give a curve whose normal at any point is in the direction of the resultant of the centrifugal force at that point and gravity. There is a cover to this pan whose convexity almost fits the concavity of the pan, leaving a space of about an inch between. Crushed ore with water is admitted at the center between the cover and the pan, and is driven by centrifugal force through a mass of mercury (which occupies part of this space between the two) and out over the edge of the pan. The particles of metal coming in contact with the mercury amalgamate, and as the speed is regulated so that it is never great enough to hurl the mercury out, nothing but sand, water, etc., escape. There have been many different constructions devised, but this general principle runs through all. By having annular flanges running down from the cover with openings placed alternately, the mixture is compelled to follow a tortuous course, thus giving time for all the gold or other metal to become amalgamated. There are ridges in the pan, too, against which the amalgam lodges. It is claimed for this machine that not a particle of the precious metal is lost, and experiments seem to uphold the claim.

A machine for separating fine from coarse clay for porcelain or for separating the finer quality of plumbago from the coarser for lead pencils uses an imperforate basket, against the wall of which the coarser part banks and catches under the rim. The finer part forms an inner cylindrical stratum, but is allowed to spill over the edge of the rim. The mixture is introduced at the bottom of the basket at the center.

CLASS IV., GASES AND SOLIDS.—There is a very simple contrivance illustrating machines of this class used to free air from dust or other heavy solid impurities which may be in suspension. See Fig. 33. The air enters the passage, B (if it has no considerable velocity of itself, it must be forced in), forms a whirlpool in the conically shaped receptable, A, and passes up out of the passage, D. The heavy particles are thrown on the sides and collect there and fall through opening, C, into some closed receiver.



CLASS V., GASES AND LIQUIDS.—The occluded gases in steel and other metal castings, if not separated, render the castings more or less porous. This separation is effected by subjecting the molten metal to the action of centrifugal force under exclusion of air, producing not only the most minute division of the particles, but also a vacuum, both favorable conditions for obtaining a dense metal casting.

Most of the devices for drying steam come under this head. Such are those in which the steam with the water in suspension is forced to take a circular path, by which the water is hurled by centrifugal force against the concave side of the passage and passes back to the water in the boiler.

SPEED.—The centrifugal force of a revolving particle varies, as we have seen, as the square of the angular velocity, so that the effort has been to obtain as high a number of revolutions per minute as was consistent with safety and with the principle of the machine. For example, creamers which are small and light make 4,000 revolutions per minute, though the latest styles run much more slowly. Driers and sugar machines vary from 600 to 2,000, while on the other hand the necessity of keeping the mercury from hurling off in an amalgamator prevents its turning more rapidly than sixty or eighty times a minute.

However, speed in another sense, the speed with which the operation is performed, is what especially characterizes centrifugal extractors. In this particular a contrast between the old methods and the new is impressive. Under the action of gravity, cream rises to the milk's surface, but compare the hours necessary for this to the almost instantaneous separation in a centrifugal creamer. The sugar manufacturer trusted to gravity to drain the sirup from his crystals, but the operation was long and at best imperfect. An average sugar centrifugal will separate 600 pounds of magma perfectly in three minutes. Gold quartz which formerly could not pay for its mining is now making its owners' fortunes. It is boasted by a Southern company that whereas they were by old methods making twenty-five cents per ton of gold quartz, they now by the use of the latest amalgamator make twenty-five dollars. Centrifugal force, as applied in extractors, has opened up new industries and enlarged old ones, has lowered prices and added to our comforts, and centrifugal extractors may well command, as they do, the admiration of all as wonderful examples of the way in which this busy age economizes time.

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A NEW TYPE OF RAILWAY CAR.



Figs. 1 and 2 give a perspective view and plan of a new style of car recently adopted by the Bone-Guelma Railroad Company, and which has isolated compartments opening upon a lateral passageway. In this arrangement, which is due to Mr. Desgranges, the lateral passageway does not extend all along one side of the car, but passes through the center of the latter and then runs along the opposite side so as to form a letter S. The car consists in reality of two boxes connected beneath the transverse passageway, but having a continuous roof and flooring. The two ends are provided with platforms that are reached by means of steps, and that permit one to enter the corresponding half of the car or to pass on to the next. The length from end to end is 33 feet in the mixed cars, comprising two first-class and four second-class compartments, and 32 feet in cars of the third class, with six compartments. The width of the compartments is 5.6 and 5 feet, according to the class. The passageway is 28 inches in width in the mixed cars, and 24 in those of the third class. The roof is so arranged as to afford a circulation of cool air in the interior.



The application of the zigzag passageway has the inconvenience of slightly elongating the car, but it is advantageous to the passengers, who can thus enjoy a view of the landscape on both sides of the train.—La Nature.

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FOUNDATIONS OF THE CENTRAL VIADUCT OF CLEVELAND, O.

The Central viaduct, now under construction in the city of Cleveland, is probably the longest structure of the kind devoted entirely to street traffic. The superstructure is in two distinct portions, separated by a point of high ground. The main portion, extending across the river valley from Hill street to Jennings avenue, is 2,840 feet long on the floor line, including the river bridge, a swing 233 feet in length; the other portion, crossing Walworth run from Davidson street to Abbey street, is 1,093 feet long. Add to these the earthwork and masonry approaches, 1,415 feet long, and we have a total length of 5,348 feet. The width of roadway is 40 feet, sidewalks 8 feet each. The elevation of the roadway above the water level at the river crossing is 102 feet. The superstructure is of wrought iron, mainly trapezoidal trusses, varying in length from 45 feet to 150 feet. The river piers are of first-class masonry, on pile and timber foundations. The other supports of the viaduct are wrought iron trestles on masonry piers, resting on broad concrete foundations. The pressure on the material beneath the concrete, which is plastic blue clay of varying degrees of stiffness mixed with fine sand, is about one ton per square foot.

The Cuyahoga valley, which the viaduct crosses from bluff to bluff, is composed mainly of blue clay to a depth of over 150 feet below the river level. No attempt is made to carry the foundation to the rock. White oak piles from 50 to 60 feet in length and 10 inches in diameter at small end are driven for the bridge piers either side of the river bed, and these are cut off with a circular saw 18 feet below the surface of the water. Excavation by dredging was made to a depth of 3 feet below where the piles are cut off to allow for the rising of the clay during the driving of the piles. The piles are spaced about 2 feet 5 inches each way, center to center. The grillage or platform covering the piles consists of 14 courses of white oak timber, 12 inches by 12 inches, having a few pine timbers interspersed so as to allow the mass to float during construction. The lower half of the platform was built on shore, care being taken to keep the lower surface of the mass of timber out of wind. The upper and lower surfaces of each timber were dressed in a Daniels planer, and all pieces in the same course were brought to a uniform thickness. The timbers in adjacent courses are at right angles to each other. The lower course is about 58 feet by 22 feet, the top course about 50 by 24 feet, thus allowing four steps of one foot each all around. The first course of masonry is 48 feet by 21 feet 8 inches; the first course of battered work is 41 feet 81/2 inches by 16 feet 3 inches. Thus the area of the platform on the piles is 1,856 square feet, and of the first batter course of masonry 777.6 square feet, or in the ratio of 2.4 to 1. The height of the masonry is 78 feet above the timber, or 731/2 feet above the water. The number of piles in each foundation is 312. The average load per pile is about 11 tons, and the estimated pressure per square inch of the timber on the heads of the piles is about 200 pounds.

To prevent the submersion of the lower courses of masonry during construction, temporary sides of timber were drift-bolted to the margin of the upper course of the timber platform, and carried high enough to be above the surface of the water when the platform was sunk to the head of the piles by the increasing weight of masonry.

The center pier is octagonal, and is built in the same general manner as to foundations as the shore piers, but the piles are cut off 22 feet below water, and there are eighteen courses of timber in the grillage. The diameter of the platform between parallel sides is 53 feet, while that of the lower course of battered masonry is but 37 feet. The areas are as 2,332 to 1,147, or as 2 to 1 nearly. The pressure per square inch of timber on the heads of the piles is about the same as stated above for the shore piers. The number of piles under the center pier is 483.

The risks and delays by this method of constructing the foundations were much less, and the cost also, than if an ordinary coffer dam had been used. Also the total weight of the piers is much less, as that portion below a point about two feet below the water adds nothing to their weight.

The piles were driven with a Cram steam hammer weighing two tons, in a frame weighing also two tons. The iron frame rests directly upon the head of the pile and goes down with it. The fall of the hammer is about 40 inches before striking the pile. The total penetration of the piles into the clay averaged 27 feet. The settlement of the pile during the final strokes of the hammer varied from one quarter to three quarters of an inch per blow.

There are 122 masonry pedestals, of which eight are large and heavy, carrying spans of considerable length. They will all be built upon concrete beds, except a few near the river on the north side, where piles are required.

The four abutments with their retaining walls are of first-class rock-faced masonry. The footing courses are stepped out liberally, so as to present an unusually large bottom surface. They rest on beds of concrete 4 feet thick. The foundation pits are about 50 feet below the top of the bluffs, and are in a material common to the Cleveland plateau, a mixture of blue sand and clay, with some water. The estimated load of masonry on the earth at the bottom of the concrete is one and seven tenths tons to the square foot. Two of the large abutments were completed last season. They show an average settlement of three eighths of an inch since the lower footing courses were laid.

The facts and figures here given regarding the viaduct were kindly furnished by the city civil engineer, C.G. Force, who has the work in charge.—Jour. Asso. of Eng. Societies.

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For sticking paper to zinc, use starch paste with which a little Venice turpentine has been incorporated, or else use a dilute solution of white gelatine or isinglass.

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CENTRIFUGAL PUMPS AT MARE ISLAND NAVY YARD, CALIFORNIA.[1]

[Footnote 1: Built by the Southwark Foundry and Machine Company, of Philadelphia.]

By H.R. CORNELIUS.

In December, 1883, bids were asked for by the United States government on pumping machinery, to remove the water from a dry dock for vessels of large size.

The dimensions of the dock, which is situated on San Pablo Bay, directly opposite the city of Vallejo, are as follows:

Five hundred and twenty-nine feet wide at its widest part, 36 feet deep, with a capacity at mean tide of 9,000,000 gallons.

After receiving the contract, several different sizes of pumps were considered, but the following dimensions were finally chosen: Two 42 inch centrifugal pumps, with runner 66 inches in diameter and discharge pipes 42 inches, each driven direct by a vertical engine with 28 inch diameter cylinder and 24 inch stroke.

These were completed and shipped in June, 1885, on nine cars, constituting a special train, which arrived safely at its destination in the short space of two weeks, and the pumps were there erected on foundations prepared by the government.

From the "Report of the Chief of Bureau of Yards and Docks" I quote the following account of the official tests:

"The board appointed to make the test resolved to fill the dock to about the level that would attain in actual service with a naval ship of second rate in the dock, and the tide at a stage which would give the minimum pumping necessary to free the dock. The level of the 20th altar was considered as the proper point, and the water was admitted through two of the gates of the caisson until this level was reached; they were then closed. The contents of the dock at this point is 5,963,921 gallons.

"The trial was commenced and continued to completion without any interruption in a very satisfactory manner.

"In the separate trials had of each pump, the average discharge per minute was taken of the whole process, and there was a singular uniformity throughout with equal piston speed of the engine.

"It was to be expected, and in a measure realized, that during the first moments of the operations, when the level of the water in the dock was above the center of the runner of the pumps, that the discharge would be proportioned to the work done, where no effort was necessary to maintain a free and full flow through the suction pipes; but as the level passed lower and farther away from the center there was no apparent diminution of the flow, and no noticeable addition to the load imposed on the engine. The variation in piston speed, noted during the trial, was probably due to the variation of the boiler pressure, as it was difficult to preserve an equal pressure, as it rose in spite of great care, owing to the powerful draught and easy steaming qualities of the boilers.

"After the trial of the second pump had been completed the dock was again filled through the caisson, and as both pumps were to be tried, the water was admitted to a level with the 23d altar, containing 7,317,779 gallons, which was seven feet above the center of the pumps; this was in favor of the pumps for the reasons before stated. In this case all the boilers were used.

"Everything moved most admirably, and the performance of these immense machines was almost startling. By watching the water in the dock it could be seen to lower bodily, and so rapidly that it could be detected by the eye without reference to any fixed point.

"The well which communicates with the suction tunnel was open, and the water would rise and fall, full of rapid swirls and eddies, though far above the entrance of these tunnels. Through the man hole in the discharge culvert the issuance from the pipes could be seen, and its volume was beyond conception. It flowed rapidly through the culvert, and its outfall was a solid prism of water, the full size of the tunnel, projecting far into the river.

"During a pumping period of 55 minutes, the dock had been emptied from the twenty-third to two inches above the sixth altar, containing 6,210,698 gallons, an average throughout of 112,922 gallons per minute. At one time, when the revolutions were increased to 160 per minute, the discharge was 137,797 gallons per minute. This is almost a river, and is hardly conceivable. After the pumps were stopped, on this occasion, tests were made with each in succession as to the power of the ejectors with which each is fitted to recharge the pumps.

"The valves in the discharge pipe were closed and steam admitted to the ejector, the pump being still and no water in the gauge glass on the pump casing, which must be full before the pumps will work. The suction pipe of the ejector is only two and a half inches in diameter, the steam pipe one inch in diameter. To fully charge the pumps at this point required filling the pump casing and the suction pipe containing about 2,000 gallons; this was accomplished in four minutes, and when the gauge glass was full the pump operated instantly and with certainty, discharging its full volume of water.

"I went on several occasions down in the valve pits on the ladder of the casing, and to all accessible parts while in motion at its highest speed, and there was no undue vibration, only a uniform murmur of well-balanced parts, and the peculiar clash of water against the sides of the casing as its velocity was checked by the blank spaces in the runner.

"The pumps are noisy while at work, due to the clashing of the water just mentioned, but it affords a means of detecting any faulty arrangements of the runner or unequal discharge from any of its openings. While moving at a uniform speed, this clashing has a tone whose pitch corresponds with that velocity of discharge, and if this tone is lacking in quality, or at all confused, there is want of equality of discharge through the various openings of the runner. To this part I gave close attention, and there was nothing that the ear could detect to indicate aught but the nicest adjustment. The bearings of the runners worked with great smoothness, and did not become at all heated. Through a simple, novel arrangement, these bearings are lubricated and kept cool. There is a constant circulation of water from the pumps by means of a small pipe, which completes a circuit to an annular in the bearings back to the discharge pipe while the pump is in motion, requiring no oil and making it seemingly impossible to heat these bearings.

"The large cast steel valves placed in the embouchement of the casing, it was thought, might act to check the free discharge, and arrangements were provided for raising and keeping them open by a long lever key attached to their axes of revolution, but, to our great surprise, at the first gush from the pumps these valves, weighing nearly 1,500 pounds, were lifted into their recessed chambers, giving an unobstructed opening to the flow, and they floated on its surface unsupported, save by the swiftly flowing water, without a movement, while the pump was in operation.

"The steam-actuated valves in the suction and discharge pipes worked very well, and the water cushion gave a slow, uniform motion, and without shock, either in opening or closing them.

"The engines worked noiselessly, without shock or labor. At no time during the trial was the throttle valve open more than three-eighths of an inch.

"The indicator cards taken at various intervals gave 796 horse power, and the revolutions did not exceed 160 at any time, though it was estimated that 900 horse power and 210 revolutions would be necessary to attain the requisite delivery. So that there is a large reserve of power available at any time.

"The erection of this massive machinery has been admirably done. The parts, as sent from the shops of the contractor, have matched in all cases without interference here; and, when lowered into place, its final adjustment was then made without the use of chisel or file, and has never been touched since.

"The joints of the steam and water connections were perfect, and the method of concentrating all valves, waste pipes, and important movements at the post of the engineer in charge gives him complete control of the whole system of each engine and pump without leaving his place, and reduces to a minimum the necessary attendance. All the parts are strong and of excellent design and workmanship; simple, and without ornamentation.

"Looking down upon them from a level of the pump house gallery, they are impressive and massive in their simplicity.

"The government is well worth of congratulation in possessing the largest pumping machinery of this type and of the greatest capacity in the world, and the contractors have reason to be proud of their work."—Proc. Eng. Club.

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THE PART THAT ELECTRICITY PLAYS IN CRYSTALLIZATION.

Since the discovery of the multiplying galvanometer, we know for an absolute certainty that in every chemical action there is a production of electricity in a more or less notable quantity, according to the nature of the bodies in presence. Though, in the play of affinity, there is a manifestation of electricity, is it the same with cohesion, which also is a chemical force?

We know, on another hand, that, on causing electricity to intervene, we bring about the crystallization of a large number of substances. But is the converse true? Is spontaneous crystallization accompanied with an appreciable manifestation of electricity? If we consult the annals of science and works treating on electricity in regard to this subject, we find very few examples and experiments proper to elucidate the question.

Mr. Mascart is content to say: "Some experiments seem to indicate that the solidification of a body produces electricity." Mr. Becquerel does more than doubt—he denies: "As regards the disengagement of electricity in the changing of the state of bodies, we find none." This assertion is too sweeping, for further along we shall cite facts that prove, on the contrary, that in the phenomena of crystallization (to speak of this change of state only) there is an unequivocal production of electricity. Let us remark, in the first place, that when a number of phenomena of physical and chemical order incontestably testify to the very intimate correlation that exists between the molecular motions of bodies and their electrical state, it would not be very logical to grant that electricity is absent in crystallization.

Thus, to select an example from among physical effects, the vibratory phenomena that occur in telephone transmissions, under the influence of a very feeble electric current, show us that the molecular constitution of a solid body is extremely variable, although within slight limits. The feeblest modification in the electric current may be shown by molecular motions capable of propagating themselves to considerable distances in the conducting wire. Conversely, it is logical to suppose that a modification in the molecular state of a body must bring electricity into play. If, in the phenomena of solidification, and particularly of crystallization, we collect but small quantities of electricity, that may be due to the fact that, under the experimental conditions involved, the electricity is more or less completely absorbed by the work of crystal building.

On another hand, the behavior of electricity shows in advance the multiple role that this agent may play in the various physical, chemical, and mechanical phenomena.

There is no doubt that electricity exists immovable or in circulation everywhere, latent or imperceptible, around us, and within ourselves, and that it enters as a cause into the majority of the chemical, physical, and mechanical phenomena that are constantly taking place before our eyes. A body cannot change state, nature, temperature, form, or place, even, without electricity being brought into play, and without its accompanying such modifications, if it presides therein. Like heat, it is the natural agent par excellence; it is the invisible and ever present force which, in the ultimate particles of matter, causes those motions, vibrations, and rotations that have the effect of changing the properties of bodies. Upon entering their intimate structure, it orients or groups their atoms, and separates their molecules or brings them together. From this, would it not be surprising if it did not intervene in the wonderful phenomenon of crystallization? Crystallization, in fact, depends upon cohesion, and, in the thermic theory, this force is not distinct from affinity, just as solution and dissociation are not distinct from combination.

On this occasion, it is necessary to say that, between affinity, heat, and electricity there is such a correlation, such a dependency, that physicists have endeavored to reduce to one single principle all the causes that are now distinct. The mechanical theory of heat has made a great stride in this direction.

The equivalence of the thermic, mechanical and chemical forces has been demonstrated; the only question hereafter will be to select from among such forces the one that must be adopted as the sole principle, in order to account for all the phenomena that depend upon these causes of various orders. But in the present state of science, it is not yet possible to explain completely by heat or electricity, taken isolatedly, all the effects dependent upon the causes just mentioned. We must confine ourselves for the present to a study of the relations that exist between the principal natural forces—affinity, molecular forces, heat, electricity, and light. But from the mutual dependence of such forces, it is admitted that, in every natural phenomenon, there is a more or less apparent simultaneous concurrence of these causes.

In order to explain electric or magnetic phenomena, and also those of crystallization, it is admitted that the atoms of which bodies are composed are surrounded, each of them, with a sort of atmosphere formed of electric currents, owing to which these atoms are attracted or repelled on certain sides, and produce those varied effects that we observe under different circumstances. According to this theory, then, atoms would be small electro-magnets behaving like genuine magnets. Entirely free in gases, but less so in liquids and still less so in solids, they are nevertheless capable of arranging themselves and of becoming polarized in a regular order, special to each kind of atom, in order to produce crystals of geometrical form characteristic of each species. Thus, as Mr. Saigey remarks in "Physique Moderne" (p. 181): "So long as the atmospheres of the molecules do not touch each other, no trace of cohesion manifests itself; but as soon as they come together force is born. We understand why the temperatures of fusion and solidification are fixed for the same body. Such effects occur at the precise moment at which these atmospheres, which are variable with the temperature, have reached the desired diameter."



Although the phenomenon of crystallization does not essentially depend upon temperature, but rather upon the relative quantity of liquid that holds the substance in solution, it will be conceived that a moment will arrive when, the liquid having evaporated, the atmospheres will be close enough to each other to attract each other and become polarized and symmetrically juxtaposed, and, in a word, to crystallize.

Before giving examples of the production of electricity in the phenomenon of crystallization, it will be well to examine, beforehand, the different circumstances under which electricity acts as the determining cause of crystallization or intervenes among the causes that bring about the phenomenon. In the first place, two words concerning crystallization itself: We know that crystallization is the passage, or rather the result of the passage, of a body from a liquid or gaseous state to a solid one. It occurs when the substance has lost its cohesion through any cause whatever, and when, such cause ceasing to act, the body slowly returns to a solid state.

Under such circumstances, it may take on regular, geometrical forms called crystalline. Such conditions are brought about by different processes—fusion, volatilization, solution, the dry way, wet way, and electric way. Further along, we shall give some examples of the last named means.

Let us add that crystallization may be regarded as a general property of bodies, for the majority of substances are capable of crystallizing. Although certain bodies seem to be amorphous at first sight, it is only necessary to examine their fracture with a lens or microscope to see that they are formed of a large number of small juxtaposed crystals. Many amorphous precipitates become crystalline in the long run.

In the examination of the various crystallizations that occupy us, we shall distinguish the following: (1) Those that are produced through the direct intervention of the electric current; (2) those in which electricity is manifestly produced by small voltaic couples resulting from the presence of two different metals in the solution experimented with; (3) those in which there are no voltaic couples, but in which it is proved that electricity is one of the causes that concur in the production of the phenomenon; (4) finally, those in which it is rational, through analogy with the preceding, to infer that electricity is not absent from the phenomenon.

I. We know that, by means of voltaic electricity or induction, we can crystallize a large number of substances.

Despretz tried this means for months at a time upon carbon, either by using the electricity from a Ruhmkorff coil or the current from a weak Daniell's battery. In both cases, he obtained on the platinum wires a black powder, in which were found very small octohedral crystals, having the property of polishing rubies rapidly and perfectly—a property characteristic of diamonds.

The use of voltaic apparatus of high tension has allowed Mr. Cross to form a large number of mineral substances artificially, and among these we may mention carbonate of lime, arragonite, quartz, arseniate of copper, crystalline sulphur, etc.

As regards products formed with the concurrence of electricity (oxides, sulphides, chlorides, iodides, etc.), see "Des Forces Physico-Chimiques," by Becquerel (p. 231).

There is no doubt as to the part played by electricity in the chemical effects of electro-metallurgy, but it will not prove useless for our subject to remark that when, in this operation, the current has become too weak, the deposit of metal, instead of forming in a thin, adherent, and uniform layer, sometimes occurs under the form of protuberances and crystalline, brittle nodules. When, on the contrary, the current is very strong, the deposit is pulverulent, that is, in a confused crystallization or in an amorphous state.

Further along, we shall find an application of this remark. We obtain, moreover, all the intermediate effects of cohesion, form, and color of galvanic deposits.

When, into a solution of acetate of lead, we pass a current through two platinum electrodes, we observe the formation, at the negative pole, of numerous arborizations of metallic lead that grow under the observer's eye (Fig. 1). The phenomenon is of a most interesting character when, by means of solar or electric light, we project these brilliant vegetations on a screen. One might believe that he was witness of the rapid growth of a plant (Fig. 2). The same phenomenon occurs none the less brilliantly with a solution of nitrate of silver. A large number of saline solutions are adapted to these decompositions, in which the metal is laid bare under a crystalline form. Further along we shall see another means of producing analogous ramifications, without the direct use of the electric current.—C. Decharme, in La Lumiere Electrique.

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ELECTRIC TIME.

By M. LIPPMANN.

The unit of time universally adopted, the second, undergoes only very slow secular variations, and can be determined with a precision and an ease which compel its employment. Still it is true that the second is an arbitrary and a variable unit—arbitrary, in as far as it has no relation with the properties of matter, with physical constants; variable, since the duration of the diurnal movement undergoes causes of secular perturbation, some of which, such as the friction of the tides, are not as yet calculable.

We may ask if it is possible to define an absolutely invariable unit of time; it would be desirable to determine with sufficient precision, if only once in a century, the relation of the second to such a unit, so that we might verify the variations of the second indirectly and independently of any astronomical hypothesis.

Now, the study of certain electrical phenomena furnishes a unit of time which is absolutely invariable, as this magnitude is a specific constant. Let us consider a conductive substance which may always be found identical with itself, and to fix our ideas let us choose mercury, taken at the temperature of 0 deg. C., which completely fulfills this condition. We may determine by several methods the specific electric resistance, [rho], of mercury in absolute electrostatic units; [rho] is a specific property of mercury, and is consequently a magnitude absolutely invariable. Moreover, [rho] is an interval of time. We might, therefore, take [rho] as a unit of time, unless we prefer to consider this value as an imperishable standard of time.

In fact, [rho] is not simply a quantity the measure of which is found to be in relation with the measure of time. It is a concrete interval of time, disregarding every convention established with reference to measures and every selection of unit. It may at first sight, appear singular that an interval of time is found in a manner hidden under the designation electric resistance. But we need merely call to mind that in the electrostatic system the intensities of the current are speeds of efflux and that the resistances are times, i.e., the times necessary for the efflux of the electricity under given conditions. We must, in particular, remember what is meant by the specific resistance, [rho] of mercury in the electrostatic system. If we consider a circuit having a resistance equal to that of a cube of mercury, the side of which = the unit of length, the circuit being submitted to an electromotive force equal to unity, this circuit will take a given time to be traversed by the unit quantity of electricity, and this time is precisely [rho]. It must be remarked that the selection of the unit of length, like that of the unit of mass, is indifferent, for the different units brought here into play depend on it in such a manner that [rho] is not affected.

It is now required to bring this definition experimentally into action, i.e., to realize an interval of time which may be a known multiple of [rho]. This problem may be solved in various ways,[1] and especially by means of the following apparatus.

[Footnote 1: In this system the measurement of time is not effected, as ordinarily, by observing the movements of a material system, but by experiments of equilibrium. All the parts of the apparatus remain immovable, the electricity alone being in motion. Such appliances are in a manner clepsydrae. This analogy with the clepsydrae will be perceived if we consider the form of the following experiment: Two immovable metallic plates constitute the armatures of a charged condenser, and attract each other with a force, F. If the plates are insulated, these charges remain constant, as well as the force, F. If, on the contrary, we connect the armatures of resistance, R, their charges diminish and the force, F, becomes a function of the time, t; the time, t, inversely becomes a function of P. We find t by the following formula:

t = [rho] x (lS / S[pi]es) x log hyp(F0/F)

F0 and F being the values of the force at the beginning and at the end of the time, t. The above formula is independent of the choice of units. If we wish t to be expressed in seconds, we must give [rho] the corresponding value ([rho] = 1.058 X 10^-16). If we take [rho] as a unit we make [rho] = 1, and we find the absolute value of the time by the expression:

(lS) / (8[pi]es) log hyp(F0/F)

We remark that this expression of time contains only abstract numbers, being independent of the choice of the units of length and force. S and e denote surface and the thickness of the condenser; s and l the section and the length of a column of mercury of the resistance, R. This form of apparatus enables us practically to measure the notable values of t only if the value of the resistance, R, is enormous, the arrangement described in the text has not the same inconvenience.]

A battery of an arbitrary electromotive force, E, actuates at the same time the two antagonistic circuits of a differential galvanometer. In the first circuit, which has a resistance, R, the battery sends a continuous current of the intensity, I; in the second circuit the battery sends a discontinuous series of discharges, obtained by charging periodically by means of the battery a condenser of the capacity, C, which is then discharged through this second circuit. The needle of the galvanometer remains in equilibrium if the two currents yield equal quantities of electricity during one and the same time, [tau].

Let us suppose this condition of equilibrium realized and the needle remaining motionless at zero; it is easy to write the conditions of equilibrium. During the time, [tau], the continuous current yields a E quantity of electricity = — [tau]; on the other hand, each charge of R the condenser = CE, and during the time, [tau], the number of [tau] discharges = ——-, t being the fixed time between two discharges; t [tau] and t are here supposed to be expressed by the aid of an arbitrary unit of time; the second circuit yields, therefore, a [tau] quantity of electricity equal to CE x ——-. The condition of t E [tau] equilibrium is then —-[tau] = CE x ——- ; or, more simply, t = CR. R t C and R are known in absolute values, i.e., we know that C is equal to p times the capacity of a sphere of the radius, l; we have, therefore, C = pl; in the same manner we know that R is equal to q times the resistance of a cube of mercury having l for its side. We l [rho] have, therefore, R = q[rho] —- = q ——- ; and consequently t = pq[rho]. l squared l

Such is the value of t obtained on leaving all the units undetermined. If we express [rho] as a function of the second, we have t in seconds. If we take [rho] = 1, we have the absolute value [Theta] of the same interval of time as a function of this unit; we have simply [Theta] = pq.

If we suppose that the commutator which produces the successive charges and discharges of the condenser consists of a vibrating tuning fork, we see that the duration of a vibration is equal to the product of the two abstract numbers, pq.

It remains for us to ascertain to what degree of approximation we can determine p and q. To find q we must first construct a column of mercury of known dimensions; this problem was solved by the International Bureau of Weights and Measures for the construction of the legal ohm. The legal ohm is supposed to have a resistance equal to 106.00 times that of a cube of mercury of 0.01 meter, side measurement. The approximation obtained is comprised between 1/50000 and 1/200000. To obtain p, we must be able to construct a plane condenser of known capacity. The difficulty here consists in knowing with a sufficient approximation the thickness of the stratum of air. We may employ as armatures two surfaces of glass, ground optically, silvered to render them conductive, but so slightly as to obtain by transparence Fizeau's interference rings. Fizeau's method will then permit us to arrive at a close approximation. In fine, then, we may, a priori, hope to reach an approximation of one hundred-thousandth of the value of pq.

Independently of the use which may be made of it for measuring time in absolute value, the apparatus described possesses peculiar properties. It constitutes a kind of clock which indicates, registers, and, if needful, corrects automatically its own variations of speed. The apparatus being regulated so that the magnetic needle may be at zero, if the speed of the commutator is slightly increased, the equilibrium is disturbed and the magnetic needle deviates in the corresponding direction; if on the contrary the speed diminishes, the action of the antagonistic circuit predominates, and the needle deviates in the contrary direction. These deviations, when small, are proportional to the variations of speed. They may be, in the first place, observed. They may, further, be registered, either photographically or by employing a Redier apparatus, like that which M. Mascart has adapted to his quadrant electrometer; finally, we may arrange the Redier to react upon the speed so as to reduce its variations to zero. If these variations are not completely annulled, they will still be registered and can be taken into account.

As an indicator of variations this apparatus can be of remarkable sensitiveness, which may be increased indefinitely by enlarging its dimensions.

With a battery of 10 volts, a condenser of a microfarad, 10 discharges per second, and a Thomson's differential galvanometer sensitive to 10^{-10} amperes, we obtain already a sensitiveness of 1/1000000, i.e., a variation of 1/1000000 in the speed is shown after some seconds of a deviation of one millimeter. Even the stroboscopic method does not admit of such sensitiveness.

We may therefore find, with a very close approximation, a speed always the same on condition that the solid parts of the apparatus (the condenser and the resistance) are protected from causes of variation and used always at the same temperature. Doubtless, a well-constructed astronomical clock maintains a very uniform movement; but the electric clock is placed in better conditions for invariability, for all the parts are massive and immovable; they are merely required to remain unchanged, and there is no question of the wear and tear of wheel-work, the oxidation of oils, or the variations of weight. In other words, the system formed by a condenser and a resistance constitutes a standard of time easy of preservation.

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NEW METHOD OF MAINTAINING THE VIBRATION OF A PENDULUM.

A recent number of the Comptes Rendus contains a note by M.J. Carpentier describing a method of maintaining the vibrations of a pendulum by means of electricity, which differs from previous devices of the same character in that the impulse given to the pendulum at each vibration is independent of the strength of the current employed, and that the pendulum itself is entirely free, save at the point of suspension. The vibrations are maintained, not by direct impulsion, but by a slight horizontal displacement of the point of suspension in alternate directions.

This, as M. Carpentier observes, is the method which we naturally adopt in order to maintain the amplitude of swing of a heavy body suspended from a cord held in the hand. The required movement of the point of suspension is effected by means of a polarized relay, through the coils of which the current is periodically reversed by the action of the pendulum, in a manner which will presently be explained. The armature of the relay oscillates between two stops whose distance apart is capable of fine adjustment.

It is clear, therefore, that the impulse is independent of the strength of the current in the relay, provided that the armature is brought up to the stop on either side. The reversal of the current is effected by means of a small magnet carried by the bob of the pendulum, and which as it passes underneath the point of suspension is brought close to a soft iron armature, which has the form of an arc of a circle described about the point of suspension. This armature is pivoted at its center, and thus executes vibrations synchronously with those of the pendulum. These vibrations are adjusted to a very narrow range, but are sufficient to close the contacts of a commutator which reverses the current at each semi-vibration of the pendulum.

The beauty and ingenuity of this device will readily be appreciated.

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DR. MORELL MACKENZIE.

The name of the great English laryngologist, which has long been honored by scientists of England and the Continent, has lately become familar to everyone, even in unprofessional circles, in Germany because of his operations on the Crown Prince's throat. If his wide experience and great skill enable him to permanently remove the growth from the throat of his royal patient, if his diagnosis and prognosis are confirmed, so that no fear need be entertained for the life and health of the Crown Prince, the English specialist will certainly deserve the most sincere thanks of the German nation. Every phase of this treatment, every new development, is watched with suspense and hope.

Many have been unable to suppress the expression of regret that this important case was not under the care of a German, and part of the press look upon it as unjust treatment of the German specialists. But science is international, it knows no political boundaries, and the choice of Dr. Mackenzie by the family of the Crown Prince, whose sympathy with England is natural, cannot be considered a slight to German physicians when it is taken into consideration that the German authorities pronounced the growth suspicious and advised a difficult and doubtful operation, and that Prof. v. Bergman recommended that a foreign authority be consulted. As Dr. Mackenzie removed the obstruction, which had already become threatening and, in fact, dangerous, causing a loss of voice, and promised to remove any new growth from the inside without danger to the patient, the Crown Prince naturally trusted him. Since Virchow has made a microscopic examination of the part which was cut away, and has declared the new growth to be benign, all Germans should watch the results of Dr. Mackenzie's operations with sympathy, trusting that all further growth will be prevented, and that the Crown Prince will be restored to the German people in his former state of health.



Dr. Morell Mackenzie has lately reached his fiftieth year, and has attained the height of his fame as an author and practitioner. He was born at Leytonston in 1837, and studied first in London. At the age of twenty-two he passed his examination, then practiced as physician in the London Hospital, and obtained his degree in 1862. A year later he received the Jackson prize from the Royal Society of Surgeons for his treatment of a laryngeal case.

He completed his studies in Paris, Vienna (with Siegmund), and Budapest. In the latter place he worked with Czermak, making a special study of the laryngoscope. Later he published an excellent work on "Diseases of the Throat and Nose," which was the fruit of twelve years' work. The evening before the day on which this work was to have been issued, the whole edition was destroyed by a fire which occurred in the printing establishment, and had to be reprinted from the proof sheets, which were saved. In 1870 his work "On Growths in the Throat" appeared, and he has also published many articles in the British Medical Journal, the Lancet, Medical Times and Gazette, etc., which have been translated into different languages, making his name renowned all over Europe.

Since he founded the first English hospital for diseases of the throat and chest, in London in 1863, and held the position of lecturer on diseases of the throat in the London Medical College, his career has been watched with interest by the public, and his practice in England is remarkable. Therefore it is no wonder that his lately published work "On the Hygiene of the Vocal Organs" has reached its fourth edition already. This work is read not only by physicians, but also by singers and lecturers.

As a learned man in his profession, as an experienced diagnostician, and as a skillful and fortunate practitioner, he is surpassed by none; and his ability will be well known far beyond the borders of Great Britain if fortune favors him and he restores the future Emperor of Germany to his former strength and vigor, without which we cannot imagine this knightly form. The certainty with which Dr. Mackenzie speaks of permanent cures which he has effected in similar cases, together with the clear and satisfactory report of the great pathologist Virchow, lead us to look to the future with confidence.—Illustrirte Zeitung.

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HYPNOTISM IN FRANCE.[1]

[Footnote 1: Translated for Science from Der Spinx.]

The voluntary production of those abnormal conditions of the nerves which to-day are denoted by the term "hypnotic researches" has manifested itself in all ages and among most of the nations that are known to us. Within modern times these phenomena were first reduced to a system by Mesmer, and, on this account, for the future deserve the attention of the scientific world. The historical description of this department, if one intends to give a connected account of its development, and not a series of isolated facts, must begin with a notice of Mesmer's personality, and we must not confound the more recent development of our subject with its past history.

The period of mesmerism is sufficiently understood from the numerous writings on the subject, but it would be a mistake to suppose that in Braid's "Exposition of Hypnotism" the end of this subject had been reached. In a later work I hope to show that the fundamental ideas of biomagnetism have not only had in all periods of this century capable and enthusiastic advocates, but that even in our day they have been subjected to tests by French and English investigators from which they have issued triumphant.

The second division of this historical development is carried on by Braid, whose most important service was emphasizing the subjectivity of the phenomena. Without any connection with him, and yet by following out almost exactly the same experiments, Professor Heidenhain reached his physiological explanations. A third division is based upon the discovery of the hypnotic condition in animals, and connects itself to the experimentum mirabile. In 1872 the first writings on this subject appear from the pen of the physiologist Czermak; and since then the investigations have been continued, particularly by Professor Preyer.

While England and Germany were led quite independently to the study of the same phenomena, France experienced a strange development, which shows, as nothing else could, how truth everywhere comes to the surface, and from small beginnings swells to a flood which carries irresistibly all opposition with it. This fourth division of the history of hypnotism is the more important, because it forms the foundation of a transcendental psychology, and will exert a great influence upon our future culture; and it is this division to which we wish to turn our attention. We have intentionally limited ourselves to a chronological arrangement, since a systematic account would necessarily fall into the study of single phenomena, and would far exceed the space offered to us.

James Braid's writings, although they were discussed in detail in Littre and Robin's "Lexicon," were not at all the cause of Dr. Philips' first books, who therefore came more independently to the study of the same phenomena. Braid's theories became known to him later by the observations made upon them in Beraud's "Elements of Physiology" and in Littre's notes in the translation of Mueller's "Handbook of Physiology;" and he then wrote a second brochure, in which he gave in his allegiance to braidism. His principal effort was directed to withdrawing the veil of mystery from the occurrences, and by a natural explanation relegating them to the realm of the known. The trance caused by regarding fixedly a gleaming point produces in the brain, in his opinion, an accumulation of a peculiar nervous power, which he calls "electrodynamism." If this is directed in a skillful manner by the operator upon certain points, it manifests itself in certain situations and actions that we call hypnotic. Beyond this somewhat questionable theory, both books contained a detailed description of some of the most important phenomena; but with the practical meaning of the phenomena, and especially with their therapeutic value, the author concerned himself but slightly. Just on account of this pathological side, however, a certain attention has been paid to hypnotism up to the present time.

In the year 1847 two surgeons in Poictiers, Drs. Ribaut and Kiaros, employed hypnotism with great success in order to make an operation painless. "This long and horrible work," says a journal of the day, "was much more like a demonstration in a dissecting room than an operation performed upon a living being." Although this operation produced such an excitement, yet it was twelve years later before decisive and positive official intelligence was given of these facts by Broca, Follin, Velpeau, and Guerinau. But these accounts, as well as the excellent little book by Dr. Azam, shared the fate of their predecessors. They were looked upon by students with distrust, and by the disciples of Mesmer with scornful contempt.

The work of Demarquay and Giraud Teulon showed considerable advance in this direction. The authors, indeed, fell back upon the theory of James Braid, which they called stillborn, and of which they said, "Elle est restee accrochee en route;" but they did not satisfy themselves with a simple statement of facts, as did Gigot Suard in his work that appeared about the same time. Through systematic experiments they tried to find out where the line of hypnotic phenomena intersected the line of the realm of the known. They justly recognized that hypnotism and hysteria have many points of likeness, and in this way were the precursors of the present Parisian school. They say that from magnetic sleep to the hypnotic condition an iron chain can be easily formed from the very same organic elements that we find in historical conditions.

At the same time, as if to bring an experimental proof of this assertion, Lasigue published a report on catalepsy in persons of hysterical tendencies, which be afterward incorporated into his larger work. Among his patients, those who were of a quiet and lethargic temperament, by simply pressing down the eyelids, were made to enter into a peculiar state of languor, in which cataleptic contractions were easily produced, and which forcibly recalled hypnotic phenomena. "One can scarcely imagine," says the author, "a more remarkable spectacle than that of a sick person sunk in deep sleep, and insensible to all efforts to arouse him, who retains every position in which he is placed, and in it preserves the immobility and rigidity of a statue." But this impulse also was in vain, and in only a few cases were the practical tests followed up with theoretical explanations.

Unbounded enthusiasm and unjust blame alike subsided into a silence that was not broken for ten years. Then Charles Richet, a renowned scientist, came forward in 1875, impelled by the duty he felt he owed as a priest of truth, and made some announcements concerning the phenomena of somnambulism; and in countless books, all of which are worthy of attention, he has since then considered the problem from its various sides.

He separates somnambulism into three periods. The word here is used for this whole class of subjects as Richet himself uses it, viz., torpeur, excitation, and stupeur. In the first, which is produced by the so-called magnetic passes and the fixing of the eyes, silence and languor come over the subject. The second period, usually produced by constant repetition of the experiment, is characterized chiefly by sensibility to hallucination and suggestion. The third period has as its principal characteristics supersensibility of the muscles and lack of sensation. Yet let it be noticed that these divisions were not expressed in their present clearness until 1880; while in the years between 1872 and 1880, from an entirely different quarter, a similar hypothesis was made out for hypnotic phenomena.

Jean Martin Charcot, the renowned neurologist of the Parisian Salpetriere, without exactly desiring it, was led into the study of artificial somnambulism by his careful experiments in reference to hysteria, and especially by the question of metallotherapie, and in the year 1879 had prepared suitable demonstrations, which were given in public lectures at the Salpetriere. In the following years he devoted himself to closer investigation of this subject, and was happily and skillfully assisted by Dr. Paul Richer, with whom were associated many other physicians, such as Bourneville, Regnard, Fere, and Binet. The investigations of these men present the peculiarity that they observe hypnotism from its clinical and nosographical side, which side had until now been entirely neglected, and that they observe patients of the strongest hysterical temperaments. "If we can reasonably assert that the hypnotic phenomena which depend upon the disturbance of a regular function of the organism demand for their development a peculiar temperament, then we shall find the most marked phenomena when we turn to an hysterical person."

The inferences of the Parisian school up to this time are somewhat the following, but their results, belonging almost entirely to the medical side of the question, can have no place in this discussion. They divide the phenomena of hystero-hypnotism, which they also call grande hysterie, into three plainly separable classes, which Charcot designates catalepsy, lethargy, and somnambulism.

Catalepsy is produced by a sudden sharp noise, or by the sight of a brightly gleaming object. It also produces itself in a person who is in a state of lethargy, and whose eyes are opened. The most striking characteristic of the cataleptic condition is immobility. The subject retains every position in which he is placed, even if it is an unnatural one, and is only aroused by the action of suggestion from the rigor of a statue to the half life of an automaton. The face is expressionless and the eyes wide open. If they are closed, the patient falls into a lethargy.

In this second condition, behind the tightly closed lids, the pupils of the eyes are convulsively turned upward. The body is almost entirely without sensation or power of thought. Especially characteristic of lethargy is the hyper-excitability of the nerves and muscles (hyperexcitabilite neuromusculaire), which manifests itself at the slightest touch of any object. For instance, if the extensor muscles of the arm are lightly touched, the arm stiffens immediately, and is only made flexible again by a hard rubbing of the same muscles. The nerves also react in a similar manner. The irritation of a nerve trunk not only contracts all the small nerves into which it branches, but also all those muscles through which it runs.