* * * * *



SELECTED FORMULAE.

ESSENCE OF PEPSIN.—

1. Pepsin (pure) 128 grains. Dilute muriatic acid 5 drops. Simple elixir 3 fl. ounces. Glycerin 1 " Water 16 " Angelica wine 6 "

Dissolve by agitation and filter through purified talcum.

2. Glycerole of pepsin 3 parts. Sherry wine 5 " Glycerin 1 " Simple elixir, to make 16 "

3. Pepsin in scales 64 grains. Glycerin 1 fl. ounce. Elixir taraxacum compound 1 " Alcohol 2 " Oil of cloves 1 drop. Sirup 2 fl. ounces. Dilute hydrochloric acid 1 fl. drachm. Water, to make 16 fl. ounces.

—Pharmaceutical Era.

APPLICATIONS TO INSECT BITES.—Brocq and Jacquet (Independance medicale, October 20) recommend the following for the bites of bugs, fleas and gnats:

1. Camphorated oil of chamomile 100 parts. Liquid storax 20 " Essence of peppermint 5 " M. 2. Olive oil 20 parts. Storax ointment 25 " Balsam of Peru 5 " M. 3. Naphthol 5 to 10 parts. Ether, enough to dissolve it. Menthol 1/4 to 1 part. Vaseline 100 parts.

BEAD FOR LIQUORS.—In the liquor trade, anything added to liquors to cause them to carry a "bead" and to hang in pearly drops about the side of the glass or bottle when poured out or shaken is called "beading," the popular notion being that liquor is strong in alcohol in proportion as it "beads." The object of adding a so-called "bead oil" is to impart this quality to a low-proof liquor, so that it may appear to the eye to be of the proper strength. The following formulas for "bead oil" are given:

1. Sweet almond oil 1 fl. ounce. Sulphuric acid, concentrated 1 " Sugar, lump, crushed 1 ounce. Alcohol, sufficient.

Triturate the oil and acid very carefully together in a glass, Wedgwood or porcelain mortar or other suitable vessel; add by degrees the sugar, continue trituration until the mixture becomes pasty, and then gradually add enough alcohol to render the whole perfectly fluid. Transfer to a quart bottle and wash out the mortar twice or oftener with strong alcohol until about 20 fluid ounces in all of the latter has been used, the washings to be added to the mixture in the bottle. Cautiously agitate the bottle, loosely corked, until admixture appears complete, and set aside in a cool place. This quantity of "oil" is supposed to be sufficient for 100 gallons of liquor, but is more commonly used for about 80 or 85 gallons. The liquor treated with this "oil" is usually allowed to become clearer by simple repose.

2. Soapwort, coarsely ground 13 ounces. Diluted alcohol, enough to make 1 gallon.

Extract the soapwort by maceration or percolation.

This is also intended for 80 gallons of liquor, preferably adding to the latter one-half gallon of simple sirup.

The ingredients of the above formulas, according to the "Manual of Beverages," are not injurious—not at least in the quantities required for "beading." It is said that beyond a certain degree of dilution of the liquor with water, these preparations fail to produce the intended effect. The addition of sugar or sirup increases their efficacy. —Pharmaceutical Era.

QUININE HAIR TONIC.—

1. Quinine sulphate 1 part. Tincture cantharides 10 " Glycerin 75 " Alcohol 500 " Tincture rhatany 20 " Spirit lavender 50 "

2. Tincture cinchona 50 " Tincture cantharides 25 " Peru balsam 20 " Tincture soap 150 " Cologne water 250 " Cognac 2,000 " Oil bergamot 10 " Oil sweet orange 10 " Oil rose geranium 3 "

3. Bisulphate of quinine 1/2 ounce. Vinegar of cantharides 21/2 " Spirit of rosemary 18 " Lavender water 8 " Glycerite of borax 1 " Glycerin 14 " Distilled water 80 " Caramel, sufficient to color.

—Pharmaceutical Era.

SOAP FOR REMOVING RUST.— Parts by Weight. Whiting 9 Oil soap 6 Cyanide of potassium 5 Water 60

Dissolve the soap in water over the fire and add the cyanide, then little by little the whiting. If the compound is too thick, which may be due either to the whiting or the soap employed, add a little water until a paste is made which can be run into an iron or wooden mould. This will remove rust from steel and give it a good polish.—Oils, Colors and Drysalteries.

* * * * *



THE NEWFOUNDLAND AND NOVA SCOTIA PASSENGER STEAMER "BRUCE."

Messrs A. & J. Inglis, shipbuilders and engineers, of Pointhouse, Glasgow, have recently built a somewhat unique and certainly interesting steamer, for the conveyance of passengers between Port an Basque, in Newfoundland, and Sydney, Cape Breton, in connection with the Newfoundland and Canadian systems of railways. The distance from port to port is about one hundred miles, and the vessel has been designed to make the run in six hours. Messrs. Reid, of Newfoundland, who have founded the line of steamers to perform this service, intrusted to Messrs. Inglis the task of producing a vessel in all respects suitable for the work to be accomplished. The steamer "Bruce," the pioneer steamer, an illustration of which we are enabled to produce, is the result. The navigation of the waters in which this vessel will be employed is attended with some difficulties. Not only are storms of frequent occurrence, but in the months of winter and spring large quantities of drift ice are commonly encountered.

To obtain the necessary speed and carry all that was required on a suitable draught of water, it was essential that the "Bruce" should be built of steel, but in view of the severe structural and local stresses to which she must inevitably be subjected when at sea, it was necessary to afford adequate stiffening and means for preventing penetration or abrasion by ice. Hence the frames are more closely spaced than is usual in vessels of her size, numerous web frames associated with arched supports at the main deck and adjacent to the waterline are fitted throughout her entire length, and a belt of 3-inch greenheart planking, with a steel sheathing over it at the fore part of the vessel, is further provided. Indeed, throughout the vessel, every precaution has been taken with a view to insure her efficiency and safety when running swiftly from port to port, while at the same time the materials employed have been most wisely, judiciously and economically distributed.



The dimensions of the "Bruce" are 230 feet long, 32 feet 6 inches broad, and 22 feet deep, her gross tonnage being 1250 tons. She has been built with very fine lines, a considerable rise of floor, and with a graceful outline, which gives her the appearance of a large yacht. Our illustration shows the "Bruce" when running at a speed of upward of 15 knots on the measured mile at Wemyss Bay. Not only has the structure of the vessel been skillfully designed, but her internal fittings are admirably arranged. It is really most interesting to note with what ingenuity passenger accommodation of a somewhat extensive character has been provided in so small a vessel. The "Bruce" has berths for seventy first-class and one hundred second class passengers, and the accommodation is of a very luxurious kind. The berths are between the awning and main decks, where there is also a special apartment set apart for ladies, and at the fore end for the officers' quarters. Besides these a large and handsome dining saloon is situated on the main deck, richly upholstered and fitted with unique little window recesses, which besides adding to the appearance of the apartment, furnishes additional dining accommodation. It is done up in dark mahogany panels, fringed with gold. The chairs are upholstered in blue morocco, and the floor is laid with a Turkey carpet. All the other rooms are in dark polished oak. A large smoking room is also provided on the main deck.

The "Bruce" is further fitted with a complete installation of electric lighting, together with an electric search light; has Lord Kelvin's deep sea sounding apparatus and compasses, also Caldwell's steam steering gear and winches, Weir's evaporators and pumps. Alley and McLellan's feed water filters, and Howden's forced draught. She is steam heated throughout, and in every detail of the sanitary arrangements the health and comfort of the passengers have been attended to. Six lifeboats, having accommodation for 250 people, are hung in davits. When fully laden she carries 350 tons of cargo in her holds and 250 tons of coal in her bunkers.

The contract speed for the "Bruce" was 15 knots—and to obtain this Messrs. Inglis fitted her with triple-expansion engines, which we shall illustrate in another impression, having cylinders 26 inches, 42 inches and 65 inches in diameter, with a 42 inch stroke. Steam is supplied from four boilers loaded to a pressure of 160 pounds per square inch. When on the measured mile a mean speed of about 151/4 knots was obtained with an indicated horse power of 2200, the engines running at 90 revolutions per minute.

The vessel has arrived safely at Newfoundland, having performed the voyage at a mean speed of very little under 15 knots, a most satisfactory performance. She has been running some little time on her route and been giving most satisfactory results.—We are indebted to London Engineer for the cut and description.

* * * * *



HEAT IN GREAT TUNNELS.

One phase of the construction of tunnels through the Alps was recently discussed by M. Brandicourt, secretary of the Linnaean Society of the North of France, in the columns of La Nature. He showed that only a few thousand feet below the eternal snows of that region so high a temperature may be found that workmen can scarcely live in it. Nearly all of the other difficulties encountered in those enterprises had been foreseen. This one was a great surprise. It shows how the interior heat of the earth extends above sea level into all great mountainous uplifts on the earth's surface.

During the tunneling of Mont Cenis, says M. Brandicourt, the temperature of the rock was found to be 27.5 degrees C. (81.5 degrees F.) at about 5,000 meters (16,000 feet) from the entrance. It reached 29.5 degrees (86 degrees F.) in the last 500 meters (1,600 feet) of the central part. The workmen were then about 1,600 meters (5,100 feet) below the Alpine summit, whose mean temperature is 3 degrees below zero (27 degrees F.) Thus there was a difference of 32.5 degrees: that is, one "geothermic" degree corresponded to about 50 meters.

This elevation of temperature was not at first regarded with anxiety. Soon a draught would be produced and would ameliorate the situation. It was time, for the disease known as "miner's anaemia" had begun to claim its victims.

The situation at St. Gothard was much more serious. As at Mont Cenis, a temperature of 29 degrees C. (85 degrees F.) was found about 5,000 meters from the portals of the tunnel. But there remained yet 5,000 meters of rock to pierce. In the center of the tunnel there was observed for several days a temperature of 35 degrees (95 degrees F.) Generally it did not vary much from 32.5 degrees (90.5 degrees F.), a sufficiently high degree, if we remember that the men's perspiration was transformed into water vapor, and that the air was nearly saturated with humidity. In these conditions work was very difficult, and the horses employed to remove the debris almost all succumbed.

Man can bear more than animals. In an absolutely dry air he can endure a temperature of 50 degrees (122 degrees F.) But in an atmosphere saturated with water, underground, where the breath of the workmen fills the narrow space with poisonous vapors, a temperature of even 30 degrees (86 degrees F.) entails serious consequences. In a large number of workmen the bodily heat rose to 40 degrees (104 degrees F.) and the pulse to 140 and even 150 a minute. The most robust were obliged to lay off one day out of three, and even the working day was itself reduced to five hours, instead of seven or eight.

According to Dr. Giaconni, who for ten years attended the workmen at Mont Cenis and St. Gothard, the proportion of invalids was as large as 60 to the 100.

More strange yet, the report of the physicians who dwelt at the works notes the presence among the workmen of the intestinal parasites called "ankylostomes," which have been observed in Egypt and other tropical countries, and which are the cause of what scientists call "Egyptian chlorosis" or "intertropical hyperaemia." This pathologic state is observed only in the hottest regions of the earth. The victim becomes thin, pale and dark. He is bathed in continual sweat, devoured by inextinguishable thirst, and the prey of continual fever. And thus, adds Mr. Lentherie, "the most robust mountaineer had only to pass a few months in the depths of the Alps to contract the germs of a tropical disease. Under the thick layer of snow and ice that enveloped him he had to work naked like a tropical negro or an Indian stoker on a Red Sea steamer; and in this Alpine world, where everything outside reminds one of the polar climate, he sweltered as in a caldron and often died of heat."

The bad conditions found at St. Gothard will be met also, very probably, in the new Alpine tunnels that have been projected in recent years—those at the Simplon, St. Bernard and Mont Blanc. It can be predicted that for Mont Blanc in particular the temperature of 40 degrees (104 degrees F.) will be far exceeded. M. de Lapparent even considers that the figure of 55 degrees (131 degrees F.) proposed by some geologists is moderate, and errs by defect rather than by excess.

The engineer Stockalpa, who for four years has directed one of the workshops at St. Gothard, and has made a profound study of this temperature question, does not hesitate to say that under Mont Blanc the temperature will be 33 degrees (91 degrees F.) at three kilometers from the entrance, that it will reach 50 degrees (122 degrees F.) under the Saussure Pass, and 53.5 degrees (128 degrees F.) under the Tacul Peak, falling again to 31 degrees (88 degrees F.) under the White Valley.

These are only probabilities, but they are founded on facts, and we may imagine all the preventive measures that they will render imperative.

The experience that has been acquired in these latter years has indicated the best methods of ventilation and cooling. The compressed air used in the workings produces by its escape a very sensible lowering of the temperature, which can be made still lower by using saline solutions whose freezing point is as low as -20 degrees (4 degrees F.), and which will circulate through pipes along the tunnel. The removal of the debris can be effected by electric locomotives; thus the horses, which use up the precious air, can be done away with. The electric light, which can be operated without contamination or consuming the air, will also render great service; these improvements can all be carried out with ease. Together with the preceding, they will form a group of processes that will enable us to gain the victory over the interior heat of the great Alpine tunnels.

* * * * *



AN ENGLISH STEAM FIRE ENGINE.



The machine which we illustrate has lately been constructed by Messrs. Merryweather & Sons, of Greenwich Road, with the view to combining the advantages of both horizontal and vertical steam fire engines. Hitherto the horizontal engine has been considered by some firemen to be less handy of access than the vertical, and the vertical engine has had the undoubted disadvantage of not being stoked from the footplate. By shortening the length of stroke and constructing a special pump, the makers have been able to keep the engine sufficiently high in relation to the boiler to enable the firedoor to be placed directly in the rear of the boiler and underneath the engine, thus enabling the boiler to be stoked en route, and allowing access from the footplate to the starting valve, the suction and delivery connections, the whole of the boiler fittings and feed arrangements. This enables one man to drive and stoke the engine, and to attend to the suction and delivery hoses, and it does not interfere at all with the stability of engine in traveling or at work, as the center of gravity is well below the top of the side frames. Another feature is the absence of a main steam pipe, a bracket being arranged on the cylinders containing the steam passages, to bolt directly onto the top of the boiler. The close proximity of the engine to the boiler renders it peculiarly suitable for cold climates, and times of frost, reducing the chances of the pump or feed arrangements being frozen up. The pump valves are arranged between the barrels, and are all accessible by the removal of one cover, which weighs but 12 lb. The engine, we understand, may be stopped, the cover removed, a damaged valve replaced, the cover put on again, and the engine restarted in two minutes. A slotted link is used with a crankshaft for regulating the length of stroke. All the bearings have large wearing surfaces, and substantial eccentric straps are used, the whole of the motion being simple and accessible. There are three different methods of feeding the boiler, viz., by feed pump driven by the crosshead of the main pump, by forcing water directly into the boiler from the main pump, and by an injector taking its water from a tank either supplied from the main pump or by a bucket when pumping dirty water. All the feed pipes are fitted with strainers where attached to the main pump. Drop feed lubricators are fitted on the cylinders, and an efficient system of lubrication is provided for the rest of the working parts. The carriage frame, hose box, etc., are of the same design as usually employed for engines of this class, with the exception of the fore carriage, which is fitted with a cross spring in the rear, as well as the two longitudinal springs. This arrangement makes the engine run more lightly, and removes much of the strain on the side frames when traveling rapidly on a rough road. The wheels are fairly light for the weight they have to carry, and have gun metal stock hoops with diamond pent rims to prevent the men slipping when mounting in a hurry. The engine and boiler work is brightly polished where-ever possible, and the whole machine has a handsome appearance.—Engineering.

* * * * *



APPARATUS FOR OBTAINING THE CUBATURE OF TREES.

In the exploitation of forests it is an important matter to be able to measure the cubature of trees, and the process most generally employed consists in determining their height and mean circumference, the apparatus used for this latter measurement being compasses having the form of the calipers used by mechanics. The figure indicated is read upon the graduated rule and is called off in a loud voice to another person, who at once writes it down. There are several causes of error: it is possible that the reading may be incorrectly made or improperly called off, or be misunderstood or incorrectly noted. Finally, it is a somewhat fatiguing operation that is often dispensed with and the measurement made by estimate. In order to do away with all such causes of error, M. Jobez, a mining engineer, has had M. Peccaud construct an apparatus that automatically registers all the measurements upon a paper tape analogous to that used in the Morse telegraphic apparatus.



The registering mechanism (Fig. 1) is fixed to the movable branch that forms the slide of the instrument. It is so arranged that when this branch is slid along the rule carrying the graduations, a gearing causes the revolution of a wheel, D, which carries figures corresponding to such graduation. At the same time, two feed rollers, E, cause a small portion of the paper tape (which is wound upon a spool, A) to move forward and wind around a receiving spool, B. After the apparatus has been made accurately to embrace the trunk of the tree to be measured, it is removed and a pressure given to the lever, H, which applies the paper to the type wheel, D. A special button permits, in addition, of making a dot alongside of the numbers, if it be desired to attract attention to one of the measurements, either for distinguishing one kind of a tree from another or for any other reason.

With this apparatus one man can make all the measurements and inscribe them without any possible error and without any fatigue. It is possible for him to inscribe a thousand numbers an hour, and the tapes are long enough to permit of 4,000 measurements being made without a change of paper. There is, therefore, a saving of time as well as perfect accuracy in the operation.

In order to make the calculations necessary for the estimate, M. Laurand has devised a sliding rule which facilitates the operation and which is based upon the method that consists in knowing the height and mean circumference of the tree. The circumference taken in the middle is divided by 4, 4.8 or 5 according as one employs the quarter without deduction or the sixth or fifth deduced. This first result, multiplied by itself and by the height, gives the cubature of the tree. As for the value, that is the product of this latter number by the price per cubic meter. It will be seen that there is a series of somewhat lengthy operations to be performed, and it is in order to dispense with these that has been constructed the rule under consideration, which, like all calculating rules, consists of two parts, one of which slides upon the other (Fig. 2). Upon each of these there are two graduated scales, or four in all, the first of which is designed for the circumference and the second for the height of the tree, the third for the price of the cubic meter and the fourth for the total result, that is, the value of the entire tree. The arrangements are such that, after the number corresponding to the circumference of the tree has been brought opposite that corresponding to its height, the result will be found opposite the price per cubic meter.



Thus, in the position represented in the figure, we may suppose a tree having a circumference of 2.5 m. and a height of 3.2 m.; then, if a cubic meter is worth 25 francs, the tree will be worth 20 francs.

In order to simplify the calculations and the construction of the rule, no account is taken of points; but this is of no importance, since the error that might be made in misplacing one would be so great that it would be immediately detected. A 2 franc tree would not be confounded with a 20 or a 200 franc one. As an approximation, the first two figures of the result are obtained accurately; and that suffices, because, since the whole is based upon an approximate measurement, which is the mean circumference of the tree, we cannot exact absolute precision in the results. The essential thing is to have a practically acceptable figure.—La Nature.

* * * * *

EGYPT'S POPULATION, according to the census taken last June, is 9,750,000, more than double the population in 1846. The foreign residents are 112,000; of these, 38,000 are Greeks, 24,500 Italians, 19,500 Britishers, including the army of occupation, and 14,000 French subjects, including Algerians and Tunisians. Twelve per cent. of the native males can read and write; the other Egyptians are illiterate. Cairo has 570,000 inhabitants, Alexandria 320,000, Port Said 42,000, and Suez 17,000.

* * * * *



MACHINE MOULDING WITHOUT STRIPPING PLATES.[1]

[Footnote 1: Paper presented at the New York meeting (December, 1897) of the American Society of Mechanical Engineers, and forming part of volume xix. of the Transactions.]

BY E. H. MUMFORD, PLAINFLELD, N. J.

(Member of the Society.)

Moulding machines may be classed under three heads. First, machines which only ram the moulds, and, when the ramming is done by means of a side lever, by hand, are generally called "squeezers." Second, machines which only draw the patterns, the ramming being accomplished by the usual hand methods. Third, machines which both ram the moulds and draw the patterns, ramming either by a hand-pulled lever or by fluid pressure on piston or plunger and drawing the patterns through a plate called a "stripping plate" or "drop plate"—till recently the usual method—or without the use of this plate fitting everywhere to pattern outline at the parting surface, the patterns being effectively machine guided in either case.

It is to the third class that the machine which is used to illustrate the subject of this paper belongs, and which would seem to have enough that is novel in the application of machinery to the foundry to merit the attention of the society.



At the risk of appearing pedantic, but with a view to developing an appreciation of the true function of the method of pattern drawing used in this machine, attention is called to the following sectional views of moulds and ways of drawing patterns occurring in machine moulding. Fig. 1 shows an ordinary "gate" of fitting patterns being drawn from the drag or nowel part of the mould by means of a spike and rapper wielded by the moulder's hand after cope and drag have been rammed together on a "squeezer" and cope has been removed. Frequently the pernicious "swab" is used to soak and so strengthen joint outlines of the sand before drawing patterns, in such cases as this. In this case, before cope is lifted, these patterns must be vigorously rapped through the cope; an amount depending (and so does the size of the casting) upon the mood and strength of the moulder.

Fig. 2 shows the stripping or drop plate method of drawing patterns.



In this method the patterns are not rapped at all and are drawn in a practically straight line so that the mould is absolutely pattern size.

The stripping plate is fitted accurately to every outline at the joint surface of the patterns, obviously at considerable expense, and, of course, at the instant of drawing the patterns, supports the joint surface of the mould entirely. This is, at first sight, an ideal method of drawing patterns, and it has for years been the only method practiced on machines. It has two disadvantages. The patterns are separated from the stripping plate by the necessary joint fissure between the two. Fine sand continually falls into this and, adhering to the joint surfaces more or less, grinds the fissure wider. This leads to a gradual reduction of size of patterns on vertical surfaces and a widening of the joint fissure often to such an extent that wire edges are formed on the mould, causing, on fine work, "crushing" and consequently dirty joints. A nicely fitted but worn plate of twenty-four pieces which had cost, at shop expense only, $250, was recently replaced by a plate of twenty-eight pieces, fitted ready for the machine under the new system about to be described, for not more than $25.

The stripping plate method has another drawback, not always appreciated, probably because accepted as inevitable. Stripping plate patterns are not rapped, and there frequently occur on surface of patterns, remote from the action of the stripping plate, rectangular corners just as important to mould sharply as those at the parting line. Such corners have either to be filleted or "stooled" in stripping plate work, and neither method often is practicable. When the entire pattern and plate are vibrated so that the corners where the pattern joins the plate draw perfectly, as they do in the machine to be described, it is obvious that similar corners anywhere on pattern surface will draw equally well.

The vibrating of patterns, or rather of moulds, during the operation of drawing the patterns possesses little of novelty. Ever since a bench moulder's neighbor first rapped the bench while he lifted a cope or drew a pattern, the thing has been done in one way or another. In fact, machines are now and then found on the market in which a device like a ratchet or other mechanical means for jarring the machine structure during pattern drawing renders the working of easy patterns without stripping plates possible.

The idea of applying a power driven vibrator directly to the plate carrying the patterns to thus vibrate them independently of other parts of the machine and the flask and sand has been the subject of the issue of patents to Mr. Harris Tabor, and the various figures shown will serve to illustrate the mechanism.

Briefly, the operation of the machine is as follows: The ramming head shown thrown back at the top of the machine is drawn into a vertical position after flask has been placed and filled with sand. The 3-way cock shown at the extreme left is then quickly opened, admitting compressed air of 70 to 80 pounds pressure to the inverted cylinder shown at the center of the cut. The cylinder, with the entire upper portion of the machine, is thus driven forcibly up against the ramming head, flask, sand and all. Often a single blow suffices to rain the mould—often the blow is quickly repeated, according to the demands of the particular mould in hand. Gravity returns the machine to its original position, as the 3-way cock opens to exhaust. After pushing the ramming head back and cutting sprue, if the half mould is cope, the operator seizes the lever shown just inside the 3-way cock at the right, and, drawing it forward and down, raises the outer frame of the top of machine containing the flask pins, with flask and sand thereon, away from the patterns, thus drawing them from the sand. Just as he seizes the pattern drawing lever with his right hand, he presses with his left on the head of a compression valve shown at the left side of top of machine, thus admitting air to the pneumatic vibrator already referred to.



Fig. 3, a rear view of the machine, shows at the top center, with its inlet hose hanging to it, this vibrator, which is shown in section in Fig. 4. It consists simply of a double acting elongated piston having a stroke of about 5/16 inch in a valveless cylinder and impacting upon hardened anvils at either end at the estimated rate of 5,000 blows per minute.



The method of communicating the rapid yet small oscillations of the vibrator to the patterns and yet keeping them from being transmitted to the rest of the mechanism is this:

A frame, called a vibrator frame, to which the pneumatic vibrator is bolted and keyed, is shown in Fig. 5. To this frame the plate carrying the patterns, often, in cases of patterns having irregular parting lines, forming one and the same casting with the patterns, is fastened by the four machine screws, the small tapped holes for which are shown in the corners. In fact, in changing patterns, the process consists of simply removing these four machine screws, taking up the pattern plate and screwing to the vibrator frame the new pattern plate. The vibrator frame itself is secured to the machine structure by the four larger bolts, the holes for which are shown in the inner corners. These bolts are, as shown in Fig. 7, surrounded by thick bushings. These bushings are elastic to such a degree as to absorb the sharp vibrations of vibrator frame and patterns, while so firm and well fitted as to hold patterns accurately to their position.



The action of the vibrator is such as to give to the entire pattern surface an exceedingly violent shiver, making it impossible that any sand should adhere to this surface, while the magnitude of the actual movement of the pattern is so slight that it is found to fill the mould so completely that it is impracticable to draw it a second time without rapping. Yet, so truly are the patterns held and so little disturbed from their original position, that it is perfectly practicable to return patterns to a mould having the finest ornamental surface in the ordinary practice of "printing back."

In cases where deep pockets of hanging sand occur, which cannot be held during lifting off and rolling over, machines are arranged to roll the flask over in their operation and draw the patterns up under the influence of the pneumatic vibrator, though, owing to the time consumed in the rolling over process (and each operation counts in seconds on a moulding machine) this style of machine is not usually as rapid in its working as the simpler type, in which the flasks come off in the same way they go on.



Fig. 6 shows a set of patterns as they are ordinarily fitted to plates for this machine. Round holes will be noticed at places in the plate surface. These are openings for the insertion of what are called "stools."

When it is found necessary to support the sand surface at any point, or generally, round holes are drilled through either plate or pattern surface and loose cylindrical pieces are dropped into these holes, their upper end surfaces being flush with the plate or pattern surface and their lower ends resting on the plate called, from this use, a stool plate. This plate appears in Fig. 7 at A and is hung solidly by the brackets shown at B from the frame which carries the flasks, so that it has the same upward motion as the flasks, and the upper ends of the stools remain in contact with the sand of the mould until same is lifted from machine. Fig. 7, showing a vertical section through a machine, will make perfectly clear the position and action of these stools.



As illustrating the importance of being able to work without stripping plates on a line of work which is much more extended than that possible with them, we may say that a machinist with a drill press supplied with split patterns and planed pattern plates has matched and fixed five sets of from four to eight pieces in a day: and wooden patterns fitted for temporary use in the same way are of frequent occurrence when it is not thought wise to go to the expense of metal patterns on account of the relatively small number of castings to be made from them.

It is not perhaps too much to say that pattern expense is not the final evil of the costly and not durable stripping plate patterns.

* * * * *



ARTIFICIAL INDIA RUBBER.

One of the most recent important events in the history of chemistry was the discovery by an English professor that a substance corresponding in every respect to India rubber may be produced from oil of turpentine.

Dr. W. A. Tilden, professor of chemistry in Mason College, Birmingham, began a series of experiments with a liquid hydrocarbon substance, known to chemists as isoprene, which was primarily discovered and named by Greville Williams, a well known English chemist, some years ago as a product of the destructive distillation of India rubber. In 1884, says The New York Sun, Dr. Tilden discovered that an identical substance was among the more volatile compounds obtained by the action of moderate heat upon oil of turpentine and other vegetable oils, such as rape seed oil, linseed oil and castor oil.

Isoprene is a very volatile liquid, boiling at a temperature of about 30 degrees Fahrenheit. Chemical analysis shows it to be composed of carbon and hydrogen in the proportions of five to eight.

In the course of his experiments Dr. Tilden found that when isoprene is brought into contact with strong acids, such as aqueous hydrochloric acid, for example, it is converted into a tough elastic solid, which is, to all appearances, true India rubber.

Specimens of isoprene were made from several vegetable oils in the course of Dr. Tilden's work on those compounds. He preserved several of them and stowed the bottles containing them away upon an unused shelf in his laboratory.

After some months had elapsed he was surprised at finding the contents of the bottles containing the substance derived from the turpentine entirely changed in appearance. In place of a limpid, colorless liquid the bottles contained a dense sirup, in which were floating several large masses of a solid of a yellowish color. Upon examination this turned out to be India rubber.

This is the first instance on record of the spontaneous change of isoprene into India rubber. According to the doctor's hypothesis, this spontaneous change can only be accounted for by supposing that a small quantity of acetic or formic acid had been produced by the oxidizing action of the air, and that the presence of this compound had been the means of transforming the rest.

Upon inserting the ordinary chemical test paper, the liquid was found to be slightly acid. It yielded a small portion of unchanged isoprene.

The artificial India rubber found floating in the liquid upon analysis showed all the constituents of natural rubber. Like the latter, it consisted of two substances, one of which was more soluble in benzine or in carbon bisulphide than the other. A solution of the artificial rubber in benzine left on evaporation a residue which agreed in all characteristics with the residuum of the best Para rubber similarly dissolved and evaporated.

The artificial rubber was found to unite with natural rubber in the same way as two pieces of ordinary pure rubber, forming a tough, elastic compound.

Although the discovery is very interesting from a chemical point of view, it has not as yet any commercial importance. It is from such beginnings as these, however, that cheap chemical substitutes for many natural products have been developed. Few persons outside of those directly connected with rubber industries realize the vast quantities imported yearly into this country. Last year there were brought into United States ports, as shown by the reports of the customs officers, no less than 34,348,000 pounds of India rubber. The industry has been steadily progressive since the invention of machinery for manufacturing it into the various articles of everyday use. The wonderful growth of the India rubber interests in this country will be seen from the statistics compiled in the tenth census.

In 1870 there were imported 5,132,000 pounds at an average rate of $1 per pound; in 1880 the imports were 17,835,000 pounds, at an average price of 85 cents per pound; in 1890 31,949,000 pounds were imported, at an average price of 75 cents per pound. The present price of India rubber varies from 75 cents per pound for fine Para rubber to 45 cents per pound for the cheapest grade.

It will be seen that, notwithstanding the increase in importations, the price of the raw material remains at a comparatively high figure. Many experiments have been made to find a substance possessing the same properties as India rubber, but which could be produced at a cheaper rate.

Many of the compositions which have been invented have been well adapted for use for certain purposes and have been used to adulterate the pure rubber, but no substance has been produced which could even approach India rubber in several of its important characteristics. There has never been a substance yet recommended as a substitute for rubber which possessed the extraordinary elasticity which makes it indispensable in the manufacture of so many articles of common use.

Great hopes were at one time placed in a product prepared from linseed oil. It was found that a material could be produced from it which would to a certain extent equal India rubber compositions in elasticity and toughness.

It was argued that linseed oil varnish, when correctly prepared, should be clear, and dry in a few hours into a transparent, glossy mass of great tenacity. By changing the mode of preparing linseed oil varnish in so far as to boil the oil until it became a very thick fluid and spun threads, when it was taken from the boiler, a mass was obtained which in drying assumed a character resembling that of a thick, congealed solution of glue.

Resin was added to the mass while hot, in a quantity depending upon the product designed to be made, and requiring a greater or less degree of elasticity.

Many other recipes have been advocated at different times to make a product resembling caoutchouc out of linseed oil in combination with other substances, but all have failed to give satisfaction, save as adulterants to pure rubber.

Among the best compounds in use in rubber factories at present is one made by boiling linseed oil to the consistency of thick glue. Unbleached shellac and a small quantity of lampblack is then stirred in. The mass is boiled and stirred until thoroughly mixed. It is then placed in flat vessels exposed to the air to congeal.

While still warm the blocks formed in the flat vessels are passed between rollers to mix it as closely as possible. This compound was asserted by its inventor to be a perfect substitute for caoutchouc. It was also stated that it could be vulcanized. This was found to be an error, however. The compound, upon the addition of from 15 to 25 per cent. of pure rubber, may be vulcanized and used as a substitute for vulcanized rubber.

Compounds of coal tar, asphalt, etc., with caoutchouc have been frequently tested, but they can only be used for very inferior goods.

The need for a substitute for gutta percha is even more acute than for artificial India rubber. A compound used in its stead for many purposes is known as French gutta percha. This possesses nearly all the properties of gutta percha. It may be frequently used for the same purposes and has the advantage of not cracking when exposed to the air.

Its inventors claimed that it was a perfect substitute for India rubber and gutta percha, fully as elastic and tough and not susceptible to injury from great pressure or high temperature.

The composition of this ambitious substance is as follows: One part, by weight, of equal parts of wood tar oil and coal tar oil, or of the latter alone, is heated for several hours at a temperature of from 252 to 270 degrees Fahrenheit, with two parts, by weight, of hemp oil, until the mass can be drawn into threads. Then one-half part, by weight, of linseed oil, thickened by boiling, is added. To each 100 parts of the compound one-twentieth to one-tenth part of ozokerite and the same quantity of spermaceti are added.

The entire mixture is then again heated to 252 degrees Fahrenheit and one-fifteenth to one-twelfth part of sulphur is added. The substance thus obtained upon cooling is worked up in a similar manner to natural India rubber. It has not been successfully used, however, without the addition of a quantity of pure rubber to give it the requisite elasticity.

A substitute for gutta percha is obtained by boiling the bark of the birch tree, especially the outer part, in water over an open fire. This produces a black fluid mass, which quickly becomes solid and compact upon exposure to air.

Each gutta percha and India rubber factory has a formula of its own for making up substances as nearly identical with the natural product as possible, which are used to adulterate the rubber and gutta percha used in the factory. No one has as yet, however, succeeded in discovering a perfect substitute for either rubber or gutta percha.

The history of chemistry contains many instances where natural products have been supplanted by artificial compounds possessing the same properties and characteristics. One of the most notable of these is the substance known as alizarine, the coloring matter extracted from the madder root. This, like India rubber, is a hydrocarbon.

Prior to 1869 all calico printing was done with the coloring matter derived from the madder root, and its cultivation was a leading industry in the eastern and southern portions of Europe.

In 1869 alizarine was successfully produced from the refuse coal tar of gas works and the calico printing business was revolutionized.

The essence of vanilla, made from the vanilla bean, and used as a flavoring extract, has been supplanted by the substance christened vanilla by chemists, which possesses the same characteristics and is made from sawdust.

Isoprene, from which Dr. Tilden produced India rubber, is comparatively a new product, as derived from oil of turpentine. It yet remains to be seen whether rubber can be synthetically produced certainly and cheaply. The result of further experiments will be awaited with interest, as the production of artificial rubber at moderate cost would be an event of enormous importance.

* * * * *



DEEP AND FROSTED ETCHING ON GLASS.

The best means of producing these effects is by printing from a steel plate or lithographic stone on thin transfer paper, which, in turn, is made to give up the design to the surface of the glass, the exposed portions of the latter being then etched with acid.

In preparing the steel plate, a coating of varnish is prepared by mixing 200 parts by weight of oil of turpentine, 150 of Syrian asphaltum, 100 of beeswax, 50 of stearin, and 50 of Venice turpentine in the warm. The design is then copied in outline by tracing from the original, the shading being reproduced in a less detailed manner, but with fewer and bolder strokes, in order to adapt the picture to the process. It is then pricked through the tracing paper on to the varnish coating of the plate, and, after clearing out the lines with graving needles, the plate is etched with a mixture of 1 vol. of water and 4 to 7 vols. of nitric acid, either by application or immersion; in the latter event the back of the plate must be varnished over. When the metal is bitten by the acid to about 1-75 of an inch in depth, the operation is finished.

To transfer the design to the glass it is printed from the steel plate on to thin silk paper, the ink used being compounded from 500 parts of oil of turpentine, 1,500 of Syrian asphalt, 500 of beeswax, 400 of paraffin, and 300 of thick litho varnish. The printing is performed in the usual manner, and the transfer laid on the warmed surface of the glass sheet or ware to be decorated, rubbed over uniformly with a cloth to make the ink adhere to the glass, and then the paper is moistened and taken off again, leaving the imprinted design behind. It is well to have the ink fairly thick, and rely on warmth to impart the necessary fluidity; otherwise the design may come away with the paper in patches, and be imperfect.

For etching in the design on the glass, the edges of the latter are coated with the protective varnish, and then hydrofluoric acid is brushed over the exposed portions, which are thereby corroded, leaving the parts covered by the ink standing in relief. According as a clear or frosted etching is desired, the etching liquid is modified, being, for the latter purpose, composed of 500 parts of ammonium fluoride, 100 of common salt, 300 of fuming hydrofluoric acid and 30 of ammonia. This is brushed over the glass two or three times, and then rinsed off with lukewarm water. For deep etching, hydrofluoric acid is diluted with 11/2 vols. of water and stored for twenty-four hours before use. The objects are immersed in the baths for thirty to fifty minutes, and kept quite still the while. If the etching is to be left clear, the acid is neutralized by boiling the glass in soda, but if to be frosted afterward it is coated with the first named etching liquid while still damp. Finally, the ink is washed off with turpentine, the glass rubbed over with sawdust, washed in hot lye and rinsed with water.

Grained or lined designs can be very suitably printed from a litho stone, on paper faced with a mixture of 1,500 parts of water, 250 of wheaten starch, 1,000 of glycerine and 200 of a thick solution of gum arabic, the ink for printing being prepared by melting and mixing 500 parts of pure tallow, 250 of white beeswax, 250 of liquid mastic, and 150 of pale resin, with 100 parts of lampblack, 5 of minium, and 500 of litho varnish. In transferring the design to the glass, the latter, if flat, may be passed between India rubber rollers or protected by layers of gutta percha when the pressure is applied. The impression produced by this lithographic process has to be strengthened to enable the thin coating of ink to resist the etching liquid, and this is done by dusting powdered resin over the printed surface of the glass, brushing off all that does not adhere, and causing the remainder to attach itself to the ink by means of warmth, and so form an impervious covering. The further treatment is the same as that already described. These methods are particularly suitable for reproducing landscapes, etc., on thinly flashed glass of various colors.—Diamant.

* * * * *



SLATE AND ITS APPLICATIONS.

Slate is, as we know, merely a variety of argillite. Slate quarries are found in England, Switzerland and Italy, but it is in France especially that the industry has been most extensively developed by reason of the large deposits that underlie its surface, particularly in the province of Anjou, where they extend from Trelaze to Avrille, a distance of six miles, and in the department of Ardennes, at Remogne, Fumay, etc.

Normandy, Brittany, Dauphiny and Marne likewise possess quarries, although they are not so productive.

The exploitation is commonly done in open quarry. After the vegetable mould (which in this case is called "cover") has been removed, we meet with a solid slate which it is difficult to split into laminae, and it is not until a depth of at least fifteen feet is reached that we find a material that is fit to be exploited. All the best beds of slate, in fact, improve in quality in proportion as they lie deeper under the surface, near to which they have little value. Without entering into details as to the exploitation of this product, let us say that the blocks have to be divided in the quarry, since, in the open air, they rapidly lose the property of readily splitting into thin, even laminae.



Slate has but slight affinity for water, and, moreover, resists atmospheric influences, humidity and heat pretty well.

This property renders it valuable for a large number of domestic purposes.

There is no certain proof, it is true, that it was employed by the ancients, but it is, nevertheless, extremely probable that it was used in mass at an early period for stair heads, pillars for buildings and as a material for fencing.

The exploitation of the material became especially active at the period when the idea occurred to some one to use slate for the rooting of houses. It was employed for this purpose along with tiles as far back as the eleventh century in the majority of schistose districts. It is well known, for example, that Fumay (Ardennes) at this period had a brotherhood of slate quarrymen.

A method of getting out the material and cutting it regularly was found toward the end of the twelfth century, and it was not till then that it became of general application. Moreover, with the advent of the Gothic period slate became indispensable for castle roofs, which have a conical form.

The best slate for roofing purposes is hard, heavy and of a bluish gray color. A good slate should readily split into even laminae; it should not be absorbent of water either on its face or endwise, a property evinced by its not increasing perceptibly in weight after immersion in water; and it should be sound, compact and not apt to disintegrate in the air.

For a long time past there have been used in schools slate tablets upon which the pupils write with a pencil made of soft gray schist. This application, which is capable of rendering services in a host of details of domestic economy, has given rise to artificial slates, which, made by a process of moulding a composition analogous to cardboard pulp, present the same advantages as ordinary slate, while being much lighter.

Along about 1834 an Englishman of the name of Magnus utilized the property that slate possesses of taking a fine polish in the invention of what are called enameled slates. These products are used especially in the manufacture of table tops, mantelpieces, altars, etc. They very closely imitate the most expensive marbles, and their properties, along with their low price, have been the cause of their introduction into the houses of all classes of the English population, as well as into those of entire Europe and America.

The ease with which slate is obtained in slabs of large dimensions has greatly contributed in recent times toward still further increasing its applications. One of the first of such applications was the substitution of it in urinals for cast iron plates, which very rapidly oxidize and become impregnated with nauseous odors that necessitate a frequent cleaning and constitute a permanent source of infection.

For a few years past, too, slate has been used, in the manufacture of vats designed for breweries. These vats, of which we show in the accompanying figure a model of the installation employed in the Ivry Brewery, are each 61/2 feet square and 5 feet in depth. For leading the beer, which, upon coming from the brewing apparatus, must rest for a few days, they are connected by a system of pipes. A second system of pipes, which in our figure is seen running along the cellar vault, serves as a cooling apparatus and maintains a temperature of 5 deg. C. above zero in the vats arranged in two rows to the right and left.

The details or even a simple enumeration of the new applications of slate would, in order to be anywhere nearly complete, necessitate a lengthy article. Let us say in conclusion that slate is substituted for wood, which is too easily attackable, and for marble, which is much more costly, in our laboratories and amphitheaters and everywhere where the manipulation and stay of easily corrupted liquids and solids require the greatest cleanliness in the material of construction.—La Science en Famille.

* * * * *



BIRTHPLACE OF THE OILCLOTH INDUSTRY.

In Kennebec County, Me., is the quiet borough of East Winthrop, for more than half a century known wherever oilcloth carpeting was used as Baileyville.

Were it not for the inventive brain of one of East Winthrop's early inhabitants, says a contemporary, the village would hardly be known across the lake, but early in the present century one of the numerous family of Maine Baileys evolved a scheme to fill his purse faster than the slow process of nature was likely to do it in growing crops.

Oilcloth carpetings were not known in the long ago, when Ezekiel Bailey pictured in his mind how they might be made, and it was in the little hamlet of East Winthrop that the conceit of their manufacture was hatched and executed. Ezekiel Bailey was, in the days prior to the war of 1812, looked upon as a very likely boy. He was studious and industrious, and while other boys of the village were out in the white oak groves setting box traps for gray squirrels, and spearing pickerel by torch light in the waters of Cobosseecontee, Ezekiel was busy in his little workshop fashioning useful things to be used about the house.

Just how and when and where he was prompted to attempt the making of oilcloth carpet nobody now living at East Winthrop seems to know. Many of the burghers thought he was "a-wastin' uv his time," but they thought different some years later when great factories for the manufacture of oilcloth floor carpeting were erected in East Winthrop, Hallowell, New Jersey, and other places.

And Ezekiel? He amassed a considerable fortune and left the path of life much easier for his kin to pursue. Having met a peddler one day, he bought a table cover made of a combination of burlap and paint. Such things were a luxury in the country at that time, and Ezekiel Bailey was shrewd enough to foresee a big demand for them if the cost could be moderated a bit. While thinking, an idea came to him, and following the idea a small voice which whispered: "Make 'em yourself." He decided to try, and there is a legend to the effect that half the farmers of the village quit work to see the first table cover.

Procuring a square of burlap, or rather enough burlap from which to fashion a square of the desired size, Ezekiel Bailey framed up the fabric as the good old grandmas used to hitch up quilts at a quilting bee, the only difference being that the burlap was framed or stretched over a table made of planed boards large enough for the full spread of the burlap. With paint and brush he began his work. The first coat was a tiller; the next, a thicker one, gave body to the cloth, and when this was rubbed down to a smooth surface the last coat was prepared. This was of a different color and was spread on thick. Then, with a straight edge, a piece of board with a true, thin edge, reaching across the whole surface of painted cloth, the finishing touches were put on. Commencing at one end of the fabric, the straight edge was moved back and forth, and straight along over the fresh paint once or twice, and the whole thing left to dry.

The first table covers were great curiosities, and the homes of the Baileys were visited by all the neighboring housewives, who were anxious to see "how they worked." Of course, it was easy to keep them clean, and they saved the woodwork of the table, which was recommendation enough. To see a cloth was to covet it, and it was not long before Ezekiel Bailey had a considerable business. Employing a boy to help him, he turned out table cloths as fast as his limited facilities would permit, and, as he progressed, new ideas for decorating took shape in his mind. In less than a year he had men out on the road selling them.

The turning out to perfection of an oilcloth carpet in those days was a task that would make a person in these piping times of labor-saving machinery wish for something easier. All the smoothing or rubbing down was done by hand. Heavy, long-bladed knives, as big as the "Sword of Bunker Hill," were used to scrape down the rough body coats of paint, and a smooth surface, on which to stamp the geometrical figures in colors, was fetched after long and laborious polishing with bricks and pumice stone.

Drummers employed by Mr. Bailey traveled to Massachusetts, to New York, and away down into the South, and ere long the demand for oilcloth carpeting became so general that other factories were built and made to chatter and clank with the new industry. There was living not far from East Winthrop at this time a shrewd, wideawake Yankee farmer named Sampson, who had kept his weather eye peeled on the progress of Ezekiel Bailey, and when housewives everywhere began to yearn for the new carpeting, taking a neighbor in as a partner, Mr. Sampson built a factory, and in a very short time was in a position to be considered a formidable rival of Mr. Bailey.

But the originator of the oilcloth carpet was not to be outdone. Discerning good returns from a plant established close to a big center of consumption, Mr. Bailey entered into a deal with New Jersey capitalists, and a big factory was set a-going in that State. A trusted employe of the Bailey concern, Levi Richardson (who still lives and is the proprietor of a modest little store in East Winthrop), was sent to New Jersey to instruct the green hands there in the art of manufacture. While thus engaged, Mr. Richardson's brain was busy with the problem of labor saving, and one day a phantom device for smoothing and rubbing down the first rough coats on the burlaps took form in his mind, and for some weeks he spent his spare time in experimenting. The result was the present patent used in most factories, whereby as much rubbing down can be done in one day as could have been accomplished in four by the old hand method. —Industrial World.

* * * * *



THE KOPPEL ELECTRIC LOCOMOTIVES.

The question of the design of small locomotives for use on pioneer lines has been always a difficult matter.

The needs of the railway contractor have called for such locomotives, for which several systems of power have been tried. In many ways the electric locomotive has distinct advantages over its rivals, steam and compressed air, for these narrow gage lines. Reviewing these advantages briefly, we see that the electrical equipment is more economical to work, as one good stationary engine develops power much more cheaply than several small locomotives. Again, the electric locomotive can be more readily designed for narrow gages than steam or compressed air locomotives.



A new system of equipment of such lines is now being introduced into this country by Mr. Arthur Koppel, of 96 Leadenhall Street, E. C. The keynote of this system is flexibility, the arrangements being such that extensions or alterations can be readily effected. In fact, the line is portable, and it is claimed also to be cheaper than the ordinary construction. The overhead conductor is employed, as can be seen from Fig. 1, which gives a general view of a locomotive and train of skips on a line actually at work abroad. The supports for the wire are not provided by separate posts and brackets in the usual way, but by arched carriers attached to the sections of railway line, thereby forming a portable section of the electric railway, as illustrated by Fig. 2. The steel carrier or "arch" is fixed to one of the sleepers, which is made of sufficient length for that purpose. On the straight line these line supports are placed about 25 yards apart. In curves of a small radius each section of tramway is provided with an arch, to keep the line of the wire as nearly as possible parallel to the curve of the line. Apart from these special extended sleepers with wire carriers attached, the line is constructed in the ordinary mariner with rails 14 lb. per yard and upward. As the electric locomotives are lighter than steam locomotives, the weight of rail required is somewhat less. The special trolley for erecting the wires along the railway line is shown in Fig. 3. This consists of an ordinary four wheeled platform wagon with ladder, and wire drum with tightening gear and clamps or grips for anchoring the trolley to the line. The wire is led over a sheave on top of the ladder and fixed to the picket post at the beginning of the line. When erecting the wire the trolley is pushed beyond the first carrier arch, clamped on to the rails, and the wire is then tightened by means of the tightening gear. It is then firmly fixed to the insulator on the carrier arch The tension in the copper wire is taken up by a second portable ladder, which is also provided with a tightening gear and can be clamped to the rails in the same manner as the trolley, so that the trolley can then be pushed behind the second carrier arch and the process previously described repeated. By the tension in the wire the carrier arches acquire the necessary stability, while without the procedure previously described it would be impossible to use such light arches attached to the sleepers. On permanent lines, the extreme ends of the wire are attached to properly anchored picket posts. On portable lines, on the other hand, the trolley with the wire drum is fixed to the rails at the end of the line, as shown in Fig. 3, so as to enable the line to be lengthened or shortened, as may be required, with ease.



Care is taken in insulating the drum and ladders so as to prevent leakage from this erecting trolley to earth. The feeders from the power house to the overhead wire and to the rails respectively are erected on light iron posts, which have also been standardized by Mr. Koppel. A specimen of these posts with an anchored stay is shown in Fig. 4. All these details are arranged for convenience of the contractor required to rapidly equip a line of railway, which can also be removed as soon as the work has been done.



The locomotive used is varied in form with the gage of the line, but we are particularly concerned with those for gages under 24 inches. One form of such locomotive without a hood to protect the driver is shown in Fig. 5. In this locomotive the gear is the same as that of the next illustration, but it is securely boxed in a watertight iron cover. The controlling gear is then placed vertically in front. Figs. 6 and 7 show the details of the electrical and mechanical parts of this locomotive when fitted with a platform at either end, and with a hood. The motor. M, is of the internal pole type, and is supported on the underframe of the wagon. A double gear is used. The first is a spur gearing, connecting the motor to a countershaft placed under the motor. This gear reduces the speed of rotation to about 200 revolutions. The countershaft is then connected to the two axles of the trolley by chain gearing. This gives the necessary flexibility between the car body and the wheel required, as the springs give to any inequality of the rails. In this gearing there is no change of speed. The underframe is provided with spring axle boxes, and also with spring buffers and drawbars. The speed of the motor can be regulated within very wide limits by the regulator, R. An effective hand brake is also provided.



For gages of 20 inches and upward the motors can be mounted on springs and attached to the running axles inside of the wagon underframe. This construction is particularly recommended by Mr. Koppel where, in order to mount heavy gradients, the dead load of the motor car must be assisted by the paying load to produce the necessary adhesion. In such cases several motor wagons would be used in the same train. As regards the working voltage, this can be varied to suit special requirements, but the locomotive we illustrate was designed for 110 volts. At this pressure its possible working speed was at least eight miles per hour. The supply of power is also a matter not referred to particularly, as in many cases a lighting plant is used by the contractors, which could also be employed to provide the necessary energy for the electric railway. The good work done by small electric locomotives in the excavation work for the Waterloo and City Railway[1] will convince our large contractors of the valuable service which electricity can render both above and below ground.—The Electrical Engineer.

[Footnote 1: Electrical Engineer, vol. xvi., p. 499.]

* * * * *

A connection between Servian and Roumanian railways is to be established by bridging the Danube. It is reported proposals have already been made to the governments interested, by the Union Bridge Company, also by British and French constructors.—Uhland's Wochenschrift.

* * * * *



LIQUID RHEOSTATS.

BY H. S. WEBB.[1]

[Footnote 1: In American Electrician.]

The object in view when the following tests were commenced was to obtain some data from which the dimensions of a liquid rheostat for the dissipation as heat of a given amount of energy could be calculated, or at least estimated, when the maximum current and E.M.F. are known. These tests were rather hastily made and are far from being as complete as I should like to have them, and are published only to answer some inquiries for information on the subject.

In the first test, an ordinary Daniell jar (61/4 inches in diameter by 8 inches deep) with horizontal sheet iron electrodes was filled with tap water. It would not carry 4 amperes for over fifteen or twenty minutes, although the jar was full of water and the plates only 3/4 inch apart. After that length of time it became too hot, causing great variation in the current on account of the large amount of gas liberated, much of which adhered to the under surface of the upper electrode. The difference of potential between the plates was 200 volts.

A run was made with 1 ampere and then with 2 amperes for one hour. In the latter case the voltage between the electrodes was about 71 volts and the temperature rose to about 167 deg. F.

From these tests it would be safe to allow a vessel with a cross section of 30.7 square inches to carry from 2 to 21/2 amperes when tap water and horizontal electrodes are used.

In test No. 2 the same jar and electrodes were used as in the preceding test, but the tap water was replaced by a saturated solution of salt water. Eleven amperes with a potential difference of 7 volts between the electrodes, which were 73/4 inches apart, were passed through the solution for three hours, and the temperature at the end of the run was 122 deg. F., and was rising very slowly.

Although the current per square inch is much greater, the watts absorbed per cubic inch is much less in this case than when water was used. With the water carrying 2 amperes the watts absorbed would be over 10 per cubic inch, while for the saturated solution of salt when carrying 11 amperes it would be only about 0.4 watt.

In test No. 3 use was made of a long, wooden rectangular trough (42 inches by 61/2 inches by 8 inches) with vertical, sheet iron electrodes. The cross section of the liquid, which was a 10 per cent. solution of salt in water, was 44 square inches, and with 10 amperes passing through the solution for 13/4 hours the temperature rose to 95 deg. F., and was rising slowly at the end of the run.

The plates were 413/4 inches apart, and at the end of the run the voltmeter across the terminals read 20. This gives a current density of nearly 1/4 ampere per square inch and 0.11 watt per cubic inch. These values are too low to be considered maximum values, for this cross section of a 10 per cent. salt solution would probably carry 13 to 15 amperes safely.

It appears that as the amount of salt in the solution is increased from zero to saturation, the maximum current carrying capacity is increased, but the watts absorbed per cubic inch are less.

A very small addition of salt to tap water makes the solution a much better conductor than the water, and reduces greatly the safe maximum watts absorbed. In using glass vessels, such as Daniell jars, there is danger of cracking the jar if the temperature rises much above 165 deg. to 175 deg. F.

In test No. 4 an ordinary whisky barrel, filled up with tap water, was used. Two horizontal circular iron plates (3/16 inch thick) were used for electrodes. The diameter of the inside of the barrel was approximately 19-1/2 inches. With the two plates 26-3/8 inches apart a difference of potential of 486 volts gave a current of 2.6 amperes. With the plates 7/8 inch apart, 228 volts gave 35.5 amperes at the end of one hour, when all the water in the barrel was very hot (175 deg. F.), and there was quite a good deal of gas given off. The current density in this case was about 0.12 ampere per square inch and the watts absorbed 30.5 per cubic inch. If it were not for the large amount of water above both electrodes, it is doubtful if this current density could have been maintained.

In test No. 5 a rectangular box, in which were placed two vertical sheet iron plates, was filled with tap water. The distance between the plates was 5/8 inch, and with a difference of potential of 414 at start and 397 at end of the run, a current of 35 amperes was kept flowing for 35 minutes. Cold tap water was kept running in between the electrodes at the rate of 6.11 pounds per minute (about 1/10 cubic foot) by means of a small rubber tube about 1/4 inch inside diameter. This test is very interesting in comparison with the preceding. The current carrying capacity, 0.3 ampere per square inch, was more than double, and the energy absorbed 183 watts per cubic inch, more than six times as great as in case where running water was not used.

The temperature in some places between the plates occasionally rose as high as 205 deg. F., and it was necessary, in order to avoid too violent ebullition, to keep the inflowing stream of water directed along the water surface between the two plates. Less water would not have been sufficient, and, of course, by using more water, the temperature could have been kept lower, or with the same temperature the watts absorbed could have been increased.

When a large current density is used, there is considerable decomposition of the iron electrodes when either salt or pure water is used, and in the case of horizontal electrodes, the under surface of the top plate may become covered with bubbles of gas, making the resistance between the plates quite variable. For large current density a horizontal top plate is not advisable, unless a large number of holes are drilled through it. A better form for the top electrode would be a hollow cylinder long enough to give sufficient surface. Washing soda is often a convenient substance to use instead of salt.

If, from experience, the size of a liquid rheostat for absorbing a given amount of energy cannot be estimated, the dimensions may be calculated approximately as follows:

Suppose, for instance, it is desired to absorb 60 amperes at 40 volts difference of potential between the electrodes. Now, it is inconvenient to obtain a saturated solution of salt, and to use tap water would require too large a cross section—especially if a barrel or trough is to be used—in order to have the resistance with the plates at a safe distance apart, small enough to give 60 amperes with 40 volts.

Let us try a 10 per cent. solution of salt. Suppose the maximum current this will carry is 1/4 ampere per square inch, which will give a cross section of the solution of at least 60 / 1/4 = 240 square inches. Now, the specific resistance per inch cube (i.e., the resistance between two opposite surfaces of a cube whose side measures 1 inch) of the 10 per cent. solution of salt used in test No. 3 was 2.12 ohms. The drop, CR, will be 2.12 x 1/4 = 0.53 volt per inch length of solution between electrodes. Hence, the electrodes will have to be 40/0.53 = 75 inches apart. This would require about three barrels connected in series. This was taken merely as an illustration, because its specific resistance was known when the current density was 1/4 ampere per square inch. This solution, however, will carry safely 1/3 ampere per square inch, but I used the previous figure, since I did not know its specific resistance for this current density, because its specific resistance will be lower for a larger current density on account of the higher temperature which it will have, for the resistance of a solution decreases as its temperature increases.

To reduce this length would require a solution of higher specific resistance, that is, a solution containing less than 10 per cent. of salt, and an increase in the cross section, since the maximum carrying capacity also diminishes as the percentage of salt diminishes. Only approximate calculations are useful because variations in temperature, amount of salt actually in solution and the rate at which heat can be radiated, all combine to give results which may vary widely from those calculated.

As a matter of fact, it is seldom necessary or advisable to use a solution containing over 2 or 3 per cent. of salt. The best way to add salt to a liquid rheostat is to make a strong solution in a separate vessel and add as much of this solution as is needed. This avoids the annoying increase in conductivity of the solution which happens when the salt itself is added and is gradually dissolved.

Liquid rheostats are ever so much more satisfactory for alternating than for direct current testing. The electrodes and solution are practically free from decomposition, and a given cross section seems to be able to carry a larger alternating than direct current—probably due partly to the absence of the scum on the surface which hinders the radiation of heat.

* * * * *



THE PROGRESS OF MEDICAL EDUCATION IN THE UNITED STATES.

A retrospective survey of the progress made and of the reforms instituted in medical education in the United States is instructive. In many respects there is cause for much congratulation, while for other reasons the situation gives rise to feelings of alarm. It is pleasing to note and it augurs well for the future that a decided advance has been made in the direction of a more thorough medical training, yet at the same time it is discouraging to observe that, despite these progressive steps, competition does not abate, but rather daily becomes more acute. Dr. William T. Slayton has just issued his small annual volume on "Medical Education and Registration in the United States and Canada." From a study of this book, which fairly bristles with facts, a sufficiently comprehensive opinion may be formed in regard to the present state of medical education in this country. According to this work, there is now a grand total of one hundred and fifty-four medical schools. Of this number, one hundred and seventeen require attendance on four annual courses of lectures, and twenty-seven require attendance on sessions of eight months, and ten on nine months each year. Twenty-nine States and the District of Columbia require an examination for license to practice medicine; eighteen of these require both a diploma from a recognized college and an examination. Fifteen States require a diploma from a college recognized by them or an examination. Five States, viz., Vermont, Michigan, Kansas, Wyoming and Nevada, have practically no laws governing the practice of medicine; Alaska the same. In order to gain a clear comprehension of the existing state of affairs, a comparison of the number of students at two periods, with a lapse of years intervening sufficient to eliminate all minor variations, will be more to the point than merely regarding the multiplication of schools. Many of these mushroom institutions are not worthy of notice, containing perhaps a dozen students, and brought into existence only for the purpose of profit or from other motives of self-interest. The number of students is as reliable an index as can be given. For instance, taking the decade between 1883-84 and 1893-94, it will be found that the students in regular schools in 1883-84 numbered 10,600; in 1893-94 they had increased to 17,601. Students in homoeopathic schools in 1883-84 were 1,267; in 1893-94, 1,666. The number of eclectic students was stationary at the two periods. The increase during the period from 1893-94 to the present time has been at about the same ratio.

These figures reveal more plainly than words the existing condition of affairs, which must, too, in the nature of things, continue until that time when all the States fall into line and resolve to adopt a four years' course of not less than eight months.

To make yet another comparison, the total number of medical schools in Austria and Germany, with a population exceeding that of this country, is twenty-nine. Great Britain, with more than half the population, has seventeen; while Russia, with one hundred million inhabitants, has nine. Of course we do not argue that America, with her immense territory and scattered population, does not need greater facilities for the study of medicine than do thickly inhabited countries, as Germany and Great Britain; but we do contend that when a city of the size of St. Louis has as many schools as Russia, the craze for multiplying these schools is being carried to absurd and harmful lengths. However, that the number of schools and their yearly supply of graduates of medicine are far beyond the demand is perfectly well known to all. The Medical Record and other medical journals have fully discussed and insisted upon that point for a considerable time. The real question at issue is by what means to remedy or at least to lessen the bad effects of the system as quickly as possible. The first and most important steps toward this desirable consummation have been already taken, and when a four years' course comes into practice throughout the country, the difficult problem of checking excessive competition will at any rate be much nearer its solution. Why should France, Germany, Great Britain and other European nations consider that a course of from five to seven years is not too long to acquire a good knowledge of medical work, while in many parts of America two or three years' training is esteemed ample for the manufacture of a full-fledged doctor? Such methods are unfair both to the public and to the medical profession, and the result is that in numerous instances the short-time graduate has either to learn most of the practical part of his duties by hard experience, to starve, or to utilize his abilities in some more lucrative path of life. Taking into consideration the fact that the theory and practice of medicine have become so extended within recent years, it must be readily conceded that four years is barely sufficient time in which to gain a satisfactory insight into their various departments. For a person, however gifted, to hope to receive an adequate medical training in two or three years is vain.

In those States in which the facilities for securing a medical education are abundant, and where the time and money to be expended are within the reach everyone, there is always the danger that an undue proportion will forsake trade in order to join the profession. This is especially the case when times are bad. Many persons seem to be possessed of the idea that the practice of medicine as a means of livelihood should be regarded as a something to fall back upon when other resources fail. Accordingly, when trade is depressed and money is scarce, there is a rush to enter its ranks. That this view of the matter is altogether an erroneous one is too self-evident to need any demonstrative proof. Again, although the question of a universal four years' course is a most important one, it must not be forgotten that examination takes almost as conspicuous a place. It is desirable that every one entering on medical studies should possess a general education. With the exception of a few unimportant schools, the entrance examinations would appear to afford the necessary test. Then comes the much more vital point of how to gage, in the fairest possible manner, the extent of the medical knowledge of those who have undergone their full term of study. For various reasons the conducting of the final examinations by professors in the school in which the student has been taught is open to many and grave objections, more especially when these professors are themselves teachers in that school. As has been pointed out in The Medical Record on more than one occasion, the most obviously fair regulation is that of independent examination by an unbiased State board. If this plan were carried into execution, medical education in America generally would rest on a firmer basis than in Great Britain, in which country the standard, although nowhere so low as in parts of the United States, still varies very considerably in the different schools. The General Medical Council of England has arrived at the conclusion that competition must be checked, and has lately brought into force two drastic measures calculated to attain this object; one is the lengthening of the course to five years, and, more recently, the abolishing of the unqualified assistant. The medical profession of America is quite as conscious of the disastrous results of competition as are its fellow practitioners on the other side, and should use every legitimate means to sweep away the evils of the present system.—Medical Record.

* * * * *



DEATHS UNDER ANAESTHETICS.

On December 17, 1897, a fatality occurred during the administration of ether. The patient, a woman aged forty-four years, who suffered from "internal cancer," was admitted for operation into the new hospital for women, Euston Road. It was considered that an operation would afford a chance of the prolongation of her life. At the time of admission the patient was in a very exhausted condition. Mrs. Keith, the anaesthetist to the hospital, administered nitrous oxide gas, followed by ether, which combination of anaesthetics the patient took well. After the expiration of thirty minutes and while the operation was in progress the patient became so collapsed that the surgeon was requested by the anaesthetist to desist from further surgical procedure and she at once complied. Resuscitative measures were at once applied, but the patient died after about ten minutes from circulatory failure arising from surgical shock and collapse. We have not received any particulars as to the means adopted to restore the woman or whether hemorrhage was severe. In all such cases posture, warmth and guarding the patient from the effects of hemorrhage are undoubtedly the most important points for attention both before and during the operation. The fact is established that both chloroform and ether cause a fall of body temperature, and so increase shock unless the trunk and limbs are kept wrapped in flannel or cotton-wool. The fall of temperature under severe abdominal and vaginal operations again is considerable. A profound anaesthesia allows of a considerable drop in arterial tension, which has been shown to be least when the limbs and pelvis are placed at a higher level than the head. Again, saline transfusion of Ringer's fluid certainly lessens the collapse in such cases when the bleeding, always severe, has been excessive. We do not doubt that such a severe operation undertaken when the patient was in a dangerous state of exhaustion was as far as possible safeguarded by every precaution, and we regret we have not been favored with the particulars of the methods employed. A death following the administration of ether is reported from the Corbett Hospital, Stourbridge.[1] The patient, aged thirty-nine years, was admitted on September 21, 1897, suffering from fracture of the right femur. A prolonged application of splints led to a stiffness with adhesions about the knee joint which were to be dealt with under an anaesthetic on December 8. Ether was given from a Clover's inhaler; one ounce was used. The induction was slightly longer than usual but was marked by no unusual phenomena. No sickness occurred during or after anaesthesia and no respiratory spasm was seen. There was a short struggling stage followed by true anaesthesia when the operation, a very brief one, was rapidly performed. The patient was then taken back to the ward and the corneal reflex was noticed as being present. Voluntary movements were also said to have been seen. Later he opened his eyes "and seemed to recognize an onlooker." After this no special supervision was exercised. A hospital porter engaged in the ward noticed the man was breathing in gasps; this was twenty minutes after the patient had been taken from the operating theater and half an hour subsequent to the first administration of the ether. The surgeons were fetched from the operating theater and found by that time that the man was dead. "He was lying with his head thrown back, so that no possible difficulty of breathing could have arisen due to his position. The eyes were open and the lips slightly parted; nor was there any sign of any struggle for breath having taken place." The ether was analyzed and found to fulfill the British Pharmacopoeia tests for purity. The necropsy revealed that the right heart was distended with venous fluid blood. The lungs also were loaded with blood, as were all the viscera. We cannot but feel that the fact shown at the post mortem examination seemed to indicate that the man died from asphyxia and not from heart failure. No doubt patients appear to resume consciousness after an anaesthetic and even mutter semi-intelligible words and recognize familiar faces. They then sink into deep sleep just like the stupefaction of the drunken, and in this condition the tongue falls back and the slightest cause—a little thick mucus or the dropping of the jaw—will completely prevent ventilation of the lungs taking place. Two very similar cases occurred in the practice of a French surgeon, who promptly opened the trachea and forced air into the lungs, with the result that both patients survived. In his cases chloroform had been given. A death under chloroform occurred at the infirmary, Kidderminster. The patient, a boy, aged eight years and nine months, suffered from a congenital hernia upon which it became necessary to operate for its radical cure. The house surgeon, Mr. Oliphant, M.B., C.M. Edin., administered chloroform from lint. In about eight minutes the breathing ceased, the operation not having then been commenced. Upon artificial respiration being adopted the child appeared to rally, but sank almost immediately and died within two minutes. The necropsy showed no organic disease. At the inquest the coroner asked Dr. Oliphant whether an inhaler was not a better means of giving chloroform, and whether that substance was not the most dangerous of the anaesthetics in common use, and received the answer that inhalers were not satisfactory for giving chloroform and that it was a matter of opinion as to which was the most dangerous anaesthetic. We so often hear that the Scotch schools never meet with casualties under anaesthetics because they always use chloroform, and prefer to dispense with any apparatus, that we can readily accept the replies given to the coroner as representing the views current among the majority of even the thoughtful alumni of those great centers of medical training. A glance over the long list of casualties under chloroform will unfortunately show that whatever charm Syme exercised during his life has not survived to his followers, and overdosage with chloroform proves as fatal in the hands of those who hail from beyond the Tweed as well as "down south." A death from chloroform contained in the A.C.E. mixture occurred at the General Hospital, Birmingham, on December 15. The patient, a girl, aged five years and ten months, suffered from hypertrophied tonsils and post-nasal adenoid growths. She was given the A.C.E. mixture by Mr. McCardie, one of the anaesthetists to the institution, and tonsillotomy was performed. As consciousness was returning some chloroform was given to enable Mr. Haslam, the operator, to remove the growths. She died at once from respiratory failure, in spite of restorative measures. A necropsy showed absence of organic disease. The anaesthetist regarded the death as one from cardiac failure due to reflex inhibition by irritation of the vagus. We are not told the posture of the child or the method employed.—The Lancet.

[Footnote 1: We are indebted to Mr. Hammond Smith, honorary surgeon to the hospital, and Mr. Edgar Collis for the notes of the case.—Ed. Lancet]

* * * * *

The resistance of nickel steel to the attack of water increases with the nickel contents. The least expanding alloys, containing about 36 per cent. of nickel, are sufficiently unassailable, and can be exposed for months to air saturated with moisture without being tainted by rust. With a view of testing the expansion of nickel steel, experiments have been carried out by allowing measuring rods to remain in warm water for some hours, according to The Iron and Coal Trades Review. They were not wiped off when taken out, but were exposed for a longer period to hot steam, but the lines traced on the polished surfaces were not altered. The rough surfaces, when exposed to steam, were covered after several days with a continuous, but little adhesive, coat of rust.