Returning for a moment to the subject of the relation between the plan and the exterior design, it should be noted that the plan of a building being practically the first consideration, and the basis of the whole design, the latter should be in accordance with the principle of disposition of the plan. For example, if we have an elevation (shown in diagram) showing two wings of similar design on either side of a center, designed so as to convey the idea of a grand gallery, with a suite of apartments on either side of similar importance—if the one side only of the plan contains such a suite, and the opposite side is in reality divided up into small and inferior rooms, filled in as well as may be behind the architectural design—the whole design is in that case only a blind or screen, giving a false exterior symmetry to a building which is not so planned. This is an extreme case (or might be called so if it were not actually of pretty frequent occurrence); but it illustrates in a broad sense a principle which must be carried out in all cases, if the architecture is to be a real expression of the facts of the building.

In this lecture, which is concerned with general principles, a word may fittingly be said as to the subject of proportion, concerning which there are many misapprehensions. The word may be, and is, used in two senses, first in regard to the general idea suggested in the words "a well proportioned building." This expression, often vaguely used, seems to signify a building in which the balance of parts is such as to produce an agreeable impression of completeness and repose. There is a curious kind of popular fallacy in regard to this subject, illustrated in the remark which used to be often made about St. Peter's, that it is so well proportioned that you are not aware of its great size, etc.—a criticism which has been slain over and over again, but continues to come to life again. The fact that this building does not show its size is true. But the inference drawn is the very reverse of the truth. One object in architectural design is to give full value to the size of a building, even to magnify its apparent size; and St. Peter's does not show its size, because it is ill proportioned, being merely like a smaller building, with all its parts magnified. Hence the deception to the eye, which sees details which it is accustomed to see on a smaller scale, and underrates their actual size, which is only to be ascertained by deliberate investigation. This confusion as to scale is a weakness inherent in the classical forms of columnar architecture, in which the scale of all the parts is always in the same proportion to each other and to the total size of the building so that a large Doric temple is in most respects only a small one magnified. In Gothic architecture the scale is the human figure, and a larger building is treated, not by magnifying its parts, but by multiplying them. Had this procedure been adopted in the case of St. Peter's, instead of merely treating it with a columnar order of vast size, with all its details magnified in proportion, we should not have the fault to find with it that it does not produce the effect of its real size. In another sense, the word "proportion" in architecture refers to the system of designing buildings on some definite geometrical system of regulating the sizes of the different parts. The Greeks certainly employed such a system, though there are not sufficient data for us to judge exactly on what principle it was worked out. In regard to the Parthenon, and some other Greek buildings, Mr. Watkiss Lloyd has worked out a very probable theory, which will be found stated in a paper in the "Transactions of the Institute of Architects."

Vitruvius gives elaborate directions for the proportioning of the size of all the details in the various orders; and though we may doubt whether his system is really a correct representation of the Greek one, we can have no doubt that some such system was employed by them. Various theorists have endeavored to show that the system has prevailed of proportioning the principal heights and widths of buildings in accordance with geometrical figures, triangles of various angles especially; and very probably this system has from time to time been applied, in Gothic as well as in classical buildings. This idea is open to two criticisms, however. First, the facts and measurements which have been adduced in support of it, especially in regard to Gothic buildings, are commonly found on investigation to be only approximately true. The diagram of the section of the building has nearly always, according to my experience, to be "coaxed" a little in order to fit the theory; or it is found that though the geometrical figure suggested corresponds exactly with some points on the plan or section, these are really of no more importance than other points which might just as well have been taken. The theorist draws our attention to those points in the building which correspond with his geometry, and leaves on one side those which do not. Now it may certainly be assumed that any builders intending to lay out a building on the basis of a geometrical figure would have done so with precise exactitude, and that they would have selected the most obviously important points of the plan or section for the geometrical spacing. In illustration of this point, I have given (Fig. 25) a skeleton diagram of a Roman arch, supposed to be set out on a geometrical figure. The center of the circle is on the intersection of lines connecting the outer projection of the main cornice with the perpendiculars from those points on the ground line. This point at the intersection is also the center of the circle of the archway itself. But the upper part of the imaginary circle beyond cuts the middle of the attic cornice. If the arch were to be regarded as set out in reference to this circle, it should certainly have given the most important line—the top line, of the upper cornice, not an inferior and less important line; and that is pretty much the case with all these proportion theories (except in regard to Greek Doric temples); they are right as to one or two points of the building, but break down when you attempt to apply them further. It is exceedingly probable that many of these apparent geometric coincidences really arise, quite naturally, from the employment of some fixed measure of division in setting out buildings. Thus, if an apartment of somewhere about 30 feet by 25 feet is to be set out, the builder employing a foot measure naturally sets out exactly 30 feet one way and 25 feet the other way. It is easier and simpler to do so than to take chance fractional measurements. Then comes your geometrical theorist, and observes that "the apartment is planned precisely in the proportion of six to five." So it is, but it is only the philosophy of the measuring-tape, after all. Secondly, it is a question whether the value of this geometrical basis is so great as has sometimes been argued, seeing that the results of it in most cases cannot be judged by the eye. If, for instance, the room we are in were nearly in the proportion of seven in length to five in width, I doubt whether any of us here could tell by looking at it whether it were truly so or not, or even, if it were a foot out one way or the other, in which direction the excess lay; and if this be the case, the advantage of such a geometrical basis must be rather imaginary than real.



Having spoken of plan as the basis of design, I should wish to conclude this lecture by suggesting also, what has never to my knowledge been prominently brought forward, that the plan itself, apart from any consideration of what we may build up upon it, is actually a form of artistic thought, of architectural poetry, so to speak. If we take three such plans as those shown in Figs. 26, 27, and 28, typical forms respectively of the Egyptian, Greek, and Gothic plans, we certainly can distinguish a special imaginative feeling or tendency in each of them. In the Egyptian, which I have called the type of "mystery," the plan continually diminishes as we proceed inward. In the third great compartment the columns are planted thick and close, so as to leave no possibility of seeing through the building except along a single avenue of columns at a time. The gloom and mystery of a deep forest are in it, and the plan finally ends, still lessening as it goes, in the small and presumably sacred compartment to which all this series of colonnaded halls leads up. In the Greek plan there is neither climax nor anti-climax, only the picturesque feature of an exterior colonnade encircling the building and surrounding a single oblong compartment. It is a rationalistic plan, aiming neither at mystery nor aspiration. In the plan of Rheims (Fig. 28) we have the plan of climax or aspiration; as in the Egyptian, we approach the sacred portion through a long avenue of piers; but instead of narrowing, the plan extends as we approach the shrine. I think it will be recognized, putting aside all considerations of the style of the superstructure on these plans, that each of them in itself represents a distinct artistic conception. So in the plan of the Pantheon (Fig. 29), this entrance through a colonnaded porch into a vast circular compartment is in itself a great architectural idea, independently of the manner in which it is built up.



We may carry out this a little further by imagining a varied treatment on plan of a marked-out space of a certain size and proportion, on which a church of some kind, for instance, is to be placed. The simplest idea is to inclose it round with four walls as a parallelogram (Fig. 30), only thickening the walls where the weight of the roof principals comes. But this is a plan without an idea in it. The central or sacred space at the end is not expressed in the plan, but is merely a railed-off portion of the floor. The entrance is utterly without effect as well as without shelter. If we lay out our plan as in Fig. 31, we see that there is now an idea in it. The two towers, as they must evidently be, form an advanced guard of the plan, the recessed central part connecting them gives an effective entrance to the interior; the arrangement in three aisles gives length, the apse at the end incloses and expresses the sacrarium, which is the climax and object of the plan. The shape of the ground, however, is not favorable to the employment of a long or avenue type of plan, it is too short and square; let us rather try a plan of the open area order, such as Fig 32. This is based on the short-armed Greek cross, with an open center area; again there is an "advanced guard" in the shape of an entrance block with a porch; and the three apses at the end give architectural emphasis to the sacrarium. Fig. 35 is another idea, the special object of which is to give an effect of contrast between the entrance, approached first through a colonnaded portico, then through an internal vestibule, lighted from above, and flanked by rows of small coupled columns; then through these colonnaded entrances, the inner one kept purposely rather dark, we come into an interior expanding in every direction; an effect of strong contrast and climax. If our plot of ground again be so situated that one angle of it is opposite the vista of two or more large streets, there and nowhere else will be the salient angle, so to speak, of the plan, and we can place there a circular porch—which may, it is evident, rise into a tower—and enter the interior at the angle instead of in the center; not an effective manner of entering as a rule, but quite legitimate when there is an obvious motive for it in the nature and position of the site. A new feature is here introduced in the circular colonnade dividing the interior into a central area and an aisle. Each of these plans might be susceptible of many different styles of architectural treatment; but quite independently of that, it will be recognized that each of them represents in itself a distinct idea or invention, a form of artistic arrangement of spaces, which is what "plan," in an architectural sense, really means.

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THE LOWE INCANDESCENT GAS BURNER.

This burner is in the form of a cylinder made of a composition in which magnesium predominates, and gives a light of 210 candle power with a consumption of three and one-half cubic feet of gas per hour.



The cylinder to be heated to incandescence is firmly held in place on a metal spindle, which is slowly revolved by means of an ingenious clock-work in the base of the fixture. The arrangement is such that by turning off the gas the clock-work is stopped, and by the turning on of the gas, it is again set in motion. The movement of the spindle is so slow that a casual observer would not notice it, there being only one revolution made in twenty-four hours. The object of this movement is to continually present new surface to be heated, as that which is exposed to the high temperature wears away, similarly to the carbons used in electric lighting, though much more slowly.

These burners can be made of 2,000 candle power, down to fifty candle power.

Pure oxygen can now be obtained from the atmosphere at a cost of about twenty-five cents per 1,000 cubic feet, and the small amount required to supplement the fuel water gas in producing this light can be supplied under proper pressure from a very small pipe, which can be laid in the same trench with the fuel gas pipe, at much less cost than is required to carry an electric wire to produce an equal amount of light.

The oxygen pipe necessary to carry the gas under pressure need not exceed an inch and a half in diameter to supply 5,000 lamps of 2,000 candle power each. The only reason why this burner has not been further perfected and placed upon the market is because of the continual preoccupation of Prof. Lowe in other lines of invention, and the amount of attention required by his large business interests. Besides, the field for its usefulness has been limited, as cheap fuel gas has only just begun to be generally introduced. Now, however, that extensive preparations are being made for the rapid introduction of the Lowe fuel gas system into various cities, this burner will receive sufficient attention to shortly complete it for general use in large quantities. It is a more powerful and at the same time a softer light than is the electric incandescent or the arc light. The light-giving property of a burner of 1,000 candle power would not cost more than one cent for ten hours' lighting, and the cylinder would only require to be changed once a week; whereas the carbons of arc lights are changed daily. The cost of the gas required to maintain such a lamp ten hours would be six cents, allowing the same profit on the gas as when it is sold for other heating purposes. The lamps complete will cost much less than the present electric lamps, and after allowing a large profit to companies supplying them, will not cost consumers more than one-fourth as much as arc lamps, and will give a much clearer and steadier light.

Since Prof. Lowe perfected his first incandescent burner great progress has been made in this line of invention, and it is no wonder that the attention of the whole gas fraternity of the country has been drawn to the subject of cheap fuel water gas, which is so admirably adapted to all purposes of heat, light, and power.

While there is no doubt that light can be more cheaply produced by incandescence obtained by the use of fuel water gas than by any other means, still a large amount of electric lighting will continue to hold its position, and the electric system will gain ground for many uses. But the electric light also can be more economically produced when fuel water gas is used as power to revolve the dynamos. Therefore, we believe it to be for the best interests of every gas company that would move in the line of progress to commence without delay to make preparations for the introduction of fuel water gas, if, at first, only as supplementary to their present illuminating gas business.-Progressive Age.

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PROGRESS OF THE SORGHUM SUGAR INDUSTRY.

We are indebted to Prof. E.B. Cowgill, of Kansas, for a copy of his recent report to the Kansas State Board of Agriculture concerning the operations of the Parkinson Sugar Works, at Fort Scott, Kansas. The report contains an interesting historical sketch of the various efforts heretofore made to produce sugar from sorghum, none of which proved remunerative until 1887, when the persevering efforts of a few energetic individuals, encouraged and assisted by a small pecuniary aid from government, were crowned with success, and gave birth, it may justly be said, to a new industry which seems destined shortly to assume gigantic proportions and increase the wealth of the country.

We make the following abstracts from the report:

The sorghum plant was introduced into the United States in 1853-54, by the Patent Office, which then embraced all there was of the United States Department of Agriculture. Its juice was known to be sweetish, and chemists were not long in discovering that it contained a considerable percentage of some substance giving the reactions of cane sugar. The opinion that the reactions were due to cane sugar received repeated confirmations in the formation of true cane sugar crystals in sirups made from sorghum. Yet the small amounts that were crystallized, compared with the amounts present in the juices as shown by the analyses, led many to believe that the reactions were largely due to some other substance than cane sugar.

During the years 1878 to 1882, inclusive, while Dr. Peter Collier was chief chemist of the Department of Agriculture, much attention was given to the study of sorghum juices from canes cultivated in the gardens of the department at Washington. Dr. Collier became an enthusiastic believer in the future greatness of sorghum as a sugar producing plant, and the extensive series of analyses published by him attracted much attention.

As a result large sugar factories were erected and provided with costly appliances. Hon. John Bennyworth erected one of these at Larned, in Kansas. S.A. Liebold & Co. subsequently erected one at Great Bend.

Sterling and Hutchinson followed with factories which made considerable amounts of merchantable sugar at no profit.

The factory at Sterling was erected by R.M. Sandy & Co., of New Orleans, and while the sirup produced paid the expenses of the factory, not a crystal of sugar was made. The factory then, in 1883, changed hands, and passed under the superintendency of Prof. M.A. Scovell, then of Champaign, Illinois, who, with Prof. Webber, had worked out, in the laboratories of the Illinois Industrial University, a practical method for obtaining sugar from sorghum in quantities which at prices then prevalent would pay a profit on the business. But prices declined, and after making sugar for two years in succession, the Sterling factory succumbed.

The Hutchinson factory at first made no sugar, but subsequently passed under the management of Prof. M. Swenson, who had successfully made sugar in the laboratory of the University of Wisconsin. Large amounts of sugar were made at a loss, and the Hutchinson factory closed its doors. In 1884, Hon. W.L. Parkinson fitted up a complete sugar factory at Ottawa, and for two years made sugar at a loss. Mr. Parkinson was assisted during the first year by Dr. Wilcox, and during the second year by Prof. Swenson.

Much valuable information was developed by the experience in those several factories, but the most important of all was the fact that, with the best crushers, the average extraction did not exceed half of the sugar contained in the cane. It was known to scientists and well informed sugar makers in this country that the process of diffusion was theoretically efficient for the extraction of sugar from plant cells, and that it had been successfully applied by the beet sugar makers of Europe for this purpose.

In 1883, Prof. H.W. Wiley, chief chemist of the Department of Agriculture, made an exhaustive series of practical experiments in the laboratories of the department on the extraction of the sugars from sorghum by the diffusion process, by which the extraction of at least 85 per cent. of the total sugars present was secured.

The Kansas delegation in Congress became interested. Senator Plumb made a thorough study of the entire subject, and, with the foresight of statesmanship, gave his energies to the work of securing an appropriation of $50,000 for the development of the sugar industry, which was granted in 1884, and fifty thousand dollars more was added in 1885 to the agricultural appropriation bill. This was expended at Ottawa, Kansas, and in Louisiana.

In that year Judge Parkinson, at Fort Scott, organized the Parkinson Sugar Company. Taking up the work when all others had failed, this company has taken a full share of the responsibilities and losses, until it has at last seen the Northern sugar industry made a financial success.

The report of 1895 showed such favorable results that in 1886 the House made an appropriation of $90,000, to be used in Louisiana, New Jersey, and Kansas. A new battery and complete carbonatation apparatus were erected at Fort Scott. About $60,000 of the appropriation was expended here in experiments in diffusion and carbonatation.

Last year (1887) the Fort Scott management made careful selection of essential parts of the processes already used, omitted non-essential and cumbrous processes, availed themselves of all the experience of the past in this country, and secured a fresh infusion of experience from the beet sugar factories of Germany, and attained the success which finally places sorghum sugar making among the profitable industries of the country.

The success has been due, first, to the almost complete extraction of the sugars from the cane by the diffusion process; second, the prompt and proper treatment of the juice in defecating and evaporating; third, the efficient manner in which the sugar was boiled to grain in the strike pan.

Total number tons of cane bought 3,840 " " " seed tops bought 437 ——- Total number tons of field cane 4,277

There was something over 500 acres planted. Some of it failed to come at all, some "fell upon the rocky places, where they had not much earth, and when the sun was risen they were scorched;" so that, as nearly as we can estimate, about 450 acres of cane were actually harvested and delivered at the works. This would make the average yield of cane 91/2 tons per acre, or $19 per acre in dollars and cents.

TOTAL PRODUCT OF THE SEASON, 1887.

Sugar, 235,826 lb., @ 53/4c $13,559 98 " State bounty, @ 2c 4,716 53 ————- $17,276 50 Sirups, 51,000 gals,(estimated) @ 20c. 10,200 00 Seed (estimated) 7,000 00 ———— Value of total product $34,476 50

TOTAL COST.

Cane, 3,840 tons,@ $2 $7,680 Seed, 967 tons, @ $3 1,934 ———- $9,614 00 Labor bill from August 15 to October 15, including labor for department experiments 5,737 16 Coal, including all experiments 1,395 77 Salaries, etc. 3,500 00 Insurance, sundries, etc. 1,500 00 ————— Total $21,746 93 ========== Total value $34,476 50 Total cost 31,248 93 ————— Net $13,329 57 To be paid by the department 6,534 75 ————— Total profit for season's work, 1887 $19,764 32

OUTLINE OF THE PROCESSES OF SORGHUM SUGAR MAKING.

As now developed, the processes of making sugar from sorghum are as follows:

First, The topped cane is delivered at the factory by the farmers who can grow it.

Second, The cane is cut by a machine into pieces about one and a quarter inches long.

Third, The leaves and sheaths are separated from the cut cane by fanning mills.

Fourth, The cleaned cane is cut into fine bits called chips.

Fifth, The chips are placed in iron tanks, and the sugar "diffused," soaked out with hot water.

Sixth, The juice obtained by diffusion has its acids nearly or quite neutralized with milk of lime, and is heated and skimmed.

Seventh, The defecated or clarified juice is boiled to a semi-sirup in vacuum pans.

Eighth, The semi-sirup is boiled "to grain" in a high vacuum in the "strike pan."

Ninth, The mixture of sugar and molasses from the strike pan is passed through a mixing machine into centrifugal machines which throw out the molasses and retain the sugar.

The process of the formation of sugar in the cane is not fully determined, but analyses of canes made at different stages of growth show that the sap of growing cane contains a soluble substance having a composition and giving reactions similar to starch. As maturity approaches, grape sugar is also found in the juice. A further advance toward maturity discloses cane sugar with the other substances, and at full maturity perfect canes contain much cane sugar and little grape sugar and starchy matter.

In sweet fruits the change from grape sugar to cane sugar does not take place, or takes place but sparingly. The grape sugar is very sweet, however.

Cane sugar, called also sucrose or crystallizable sugar, when in dilute solution is changed very readily into grape sugar or glucose, a substance which is much more difficult than cane sugar to crystallize. This change, called inversion, takes place in over-ripe canes. It sets in very soon after cutting in any cane during warm weather; it occurs in cane which has been injured by blowing down, or by insects, or by frost, and it probably occurs in cane which takes a second growth after nearly or quite reaching maturity.

To insure a successful outcome from the operations of the factory, the cane must be so planted, cultivated and matured as to make the sugar in its juice. It must be delivered to the factory very soon after cutting, and it must be taken care of before the season of heavy frosts.

THE WORK AT THE FACTORY.

The operations of the factory are illustrated in the large diagram. The first cutting is accomplished in the ensilage or feed cutter at E. This cutter is provided with three knives fastened to the three spokes of a cast iron wheel which makes about 250 revolutions per minute, carrying the knives with a shearing motion past a dead knife. By a forced feed the cane is so fed as to be cut into pieces about one and a quarter inches long. This cutting frees the leaves and nearly the entire sheaths from the pieces of cane. By a suitable elevator, F, the pieces of cane, leaves and sheaths are carried to the second floor.

The elevator empties into a hopper, below which a series of four or five fans, G, is arranged one below the other. By passing down through these fans the cane is separated from the lighter leaves, much as grain is separated from chaff. The leaves are blown away, and finally taken from the building by an exhaust fan. This separation of the leaves and other refuse is essential to the success of the sugar making, for in them the largest part of the coloring and other deleterious matters are contained. If carried into the diffusion battery, these matters are extracted (see reports of Chemical Division, U.S. Department of Agriculture), and go into the juice with the sugar. As already stated, the process of manufacturing sugar is essentially one of separation. The mechanical elimination of these deleterious substances at the outset at once obviates the necessity of separating them later and by more difficult methods, and relieves the juice of their harmful influences. From the fans the pieces of cane are delivered by a screw carrier to an elevator which discharges into the final cutting machine on the third floor. This machine consists of an eight inch cast iron cylinder, with knives like those of a planing machine. It is really three cylinders placed end to end in the same shaft, making the entire length eighteen inches. The knives are inserted in slots and held in place with set screws. The cylinder revolves at the rate of about twelve hundred per minute, carrying the knives past an iron dead knife, which is set so close that no cane can pass without being cut into fine chips. From this cutter the chips of cane are taken by an elevator and a conveyer, K, to cells, MM, of the diffusion battery. The conveyer passes above and at one side of the battery, and is provided with an opening and a spout opposite each cell of the battery. The openings are closed at pleasure by a slide. A movable spout completes the connection with any cell which it is desired to fill with chips.

WHAT IS DIFFUSION?

The condition in which the sugars and other soluble substances exist in the cane is that of solution in water. The sweetish liquid is contained, like the juices of plants generally, in cells. The walls of these cells are porous. It has long been known that if a solution of sugar in water be placed in a porous or membraneous sack, and the sack placed on water, an action called osmosis, whereby the water from the outside and the sugar solution from the inside of the sack each pass through, until the liquids on the two sides of the membrane are equally sweet. Other substances soluble in water behave similarly, but sugar and other readily crystallizable substances pass through much more readily than uncrystallizable or difficultly crystallizable. To apply this properly to the extraction of sugar, the cane is first cut into fine chips, as already described, and put into the diffusion cells, where water is applied and the sugar is displaced.



THE DIFFUSION BATTERY,

as used at the Parkinson factory, consists of twelve iron tanks. (See diagram.) They are arranged in a line, as shown in diagram, Fig. 1. Each has a capacity of seventy-five cubic feet, and by a little packing holds a ton of cane chips. The cells are supported by brackets near the middle, which rest on iron joists. Each cell is provided with a heater, through which the liquid is passed in the operation of the battery. The cells are so connected by pipes and valves that the liquid can be passed into the cells, and from cell to cell, at the pleasure of the operator. The bottom of each cell consists of a door, which closes on an annular rubber hose placed in a groove, and filled with water, under a pressure greater than that ever given to the liquids in the cell. This makes a water tight joint whenever the trap door bottom is drawn up firmly against it. The upper part is of cast iron and is jug shaped, and is covered with a lid which is held with a screw on rubber packing. In the jug neck and near the bottom the sides are double, the inner plates being perforated with small holes to let water in and out. The bottoms are double, the inner plates being perforated like the neighboring sides, and for the same purpose. The cells, of whose appearance a fair idea may be had from diagram, Fig. 2, are connected with a water pipe, a juice pipe, a compressed air pipe, and the heaters, by suitable valves. The heaters are connected with a steam pipe. This, and the compressed air pipe, are not shown in the diagram. The water pipe is fed from an elevated tank, which gives a pressure of twelve pounds per square inch The valve connections enable the operator to pass water into the cells at either the top or the bottom; to pass the liquid from any cell to the next, or to the juice pipe through the heater; to separate any cell from any or all others, and to turn in compressed air.

Now let the reader refer to Fig. 2.



The cutters are started, and cell 1 is filled with chips. This done, the chips from the cutters are turned into cell 2; cell 1 is closed, and cut off from the others, and water is turned into it by opening valve, c, of cell 1 (see Fig. 2) until it is filled with water among the chips. When 2 is filled with chips, its valve, a, is raised to allow the liquid to pass down into the juice pipe. Valve a of 3 is also raised. Now the juice pipe fills, and when it is full the liquid flows through valve, a, of 3, and into the heater between 2 and 3, and into the bottom of 2, until 2 is full of water among the chips. (This may be understood by following the course of the arrows shown in the diagrams of 9 and 10). Valve a of 2 is now screwed down; c is down and b is opened. It will be readily seen by attention to the diagram that this changes the course of the flow so that it will no longer enter at the bottom, but at the top of 2, as shown by the arrows at cell 2.

It is to be observed that the water is continually pressing in at the top of 1, and driving the liquid forward whenever a valve is opened to admit it to another cell, heater, or pipe. When cell 3 is full of chips, its valves are manipulated just as were those of 2. So as each succeeding cell is filled, the manipulation of valves is repeated until cell 6 is filled with liquid. After passing through six cells of fresh chips, this liquid is very sweet, and is drawn off into the measuring tank shown at p in diagram, Fig. 1, and is thence conveyed for subsequent treatment in the factory. To draw this juice from 6, valve a of 7 is raised to connect the heater between 6 and 7 with the juice pipe. A gate valve in the juice pipe is opened into the measuring tank, and the pressure of water into the top of 1 drives the liquid forward through the bottom of 1, through the heater, into the top of 2, out from the bottom of 2, through the heater into the top of 3, out from the bottom of 3, through the heater into the top of 4, out from the bottom of 4, through the heater, into the top of 5, out from the bottom of 5, through the heater, into the top of 6, and now out from the bottom of 6, through the heater, into the juice pipe, and from the juice pipe into the measuring tank. It will be understood that the liquid which is drawn from 6 is chiefly that which was passed into 1 when it was filled with chips. There is doubtless a little mixing as the pressure drives the liquid forward. But the lighter liquid is always pressed in at the top of the cells, so that the mixing is the least possible. The amount of liquid, now called juice, which is drawn from 6 is 1,110 liters, or 291 gallons. When this quantity has been drawn into the measuring tank, the gate valve is closed, and the valves connecting with 7 are manipulated as were those of 6, a measure of juice being drawn in the same way. All this time the water has been passed into the top of 1, and this is continued until the juice has been drawn from 9. Valve c to cell 1 is now closed, and compressed air is turned into the top of 1 to drive the liquid forward into 10. After the water has thus been nearly all expelled from 1, valve a of cell 2 is lowered so as to shut off communication with the juice pipe, and b, of cell 2 is closed. a and b of cell 1 have, it will be observed, been closed or down from the beginning. Cell 1 is now isolated from all others. Its chips have been exhausted of sugar, and are ready to be thrown out. The bottom of 1 is opened, and the chips fall out into the car, o (see diagram, Fig. 1), and are conveyed away. Immediately on closing valves a and b of cell 2, c is opened, and the water presses into the top of 2, as before into the top of 1, and the circulation is precisely similar to that already described, 2 having taken the place of 1, 3 of 2, and so on.

When 2 is emptied, 3 takes the first place in the series and so on. When 12 has been filled, it takes the l3th place. (The juice pipe returns from the termination of the series, and connects with 1, making the circuit complete.) The process is continuous, and the best and most economical results are obtained if there is no intermission.

One cell should be filled and another emptied every eight minutes, so that in twenty-four hours the number of cells diffused should be one hundred and eighty.

WHAT HAS TAKEN PLACE IN THE DIFFUSION CELLS.

For the purpose of illustration, let us assume that when it has been filled with chips just as much water is passed into the cell as there was juice in the chips. The process of osmosis or diffusion sets in, and in a few minutes there is as much sugar in the liquid outside of the cane cells as in the juice in these cane cells; i.e., the water and the juice have divided the sugar between them, each taking half.

Again, assume that as much liquid can be drawn from 1 as there was water added. It is plain that if the osmotic action is complete, the liquid drawn off will be half as sweet as cane juice. It has now reached fresh chips in 2, and again equalization takes place. Half of the sugar from 1 was brought into 2, so that it now contains one and a half portions of sugar, dissolved in two portions of liquid, or the liquid has risen to three quarters of the strength of cane juice. This liquid having three fourths strength passes to 3, and we have in 3 one and three fourths portions of liquid, or after the action has taken place the liquid in 3 is seven eighths strength. One portion of this liquid passes to 4, and we have one and seven eighths portions of sugar in two portions of liquid, or the liquid becomes 15/16 strength. One portion of this liquid passes to 5, and we have in 5 one and fifteen sixteenths portions of sugar in two portions of liquid, or the liquid is 31/32 strength. It is now called juice. From this time forward a cell is emptied for every one filled.

Throughout the operation, the temperature is kept as near the boiling point as can be done conveniently without danger of filling some of the cells with steam. Diffusion takes place more rapidly at high than at low temperatures, and the danger of fermentation, with the consequent loss of sugar, is avoided.

WHAT HAS HAPPENED TO THE CHIPS.

By the first action of water in 1, 1/2 of the sugar was left in cell 1; by the second 1/4 was left, by the third 1/8 was left, by the fourth 1/16 was left, by the fifth 1/32 was left, by the sixth 1/64 was left, by the seventh 1/128 was left, by the eighth 1/256 was left, by the ninth 1/512 was left. The fractions representing the strength of the juice on the one hand and the sugar left in each cell on the other hand, after the battery is fully in operation, are not so readily deduced. The theory is easily understood, however, although the computation is somewhat intricate. Those who desire to follow the process by mathematical formula are referred to pages 9 and 10, Bulletin No. 2, Chemical Division U.S. Department of Agriculture, where will be found the formula furnished by Professor Harkness, of the U.S. Naval Observatory.

For the sake of simplifying the explanation, it was assumed that the water added is equal in volume to the juice in a cellful of cane chips. In practice more water is added, to secure more perfect exhaustion of the chips, and with the result of yielding about thirteen volumes of juice for every nine volumes as it exists in the cane, and of extracting 92.04 per cent. of all the sugars from the cane, as shown by the report of Dr. C.A. Crampton, Assistant Chemist of the U.S. Department of Agriculture.

INVERSION OF SUGAR IN THE DIFFUSION CELLS.

In the experiments at Fort Scott in 1886, much difficulty was experienced on account of inversion of the sugar in the diffusion battery. The report shows that this resulted from the use of soured cane and from delays in the operation of the battery on account of the imperfect working of the cutting and elevating machinery, much of which was there experimental. Under the circumstances, however, it became a matter of the gravest importance to find a method of preventing this inversion without in any manner interfering with the other processes. On the suggestion of Prof. Swenson, a portion of freshly precipitated carbonate of lime was placed with the chips in each cell.[1] In the case of soured cane, this took up the acid which otherwise produced inversion. In case no harmful acids were present, this chalk was entirely inactive. Soured canes are not desirable to work under any circumstances, and should be rejected by the chemist, and not allowed to enter the factory. So, also, delays on account of imperfect machinery are disastrous to profitable manufacturing, and must be avoided. But for those who desired to experiment with deteriorated canes and untried cutting machines, the addition of the calcium carbonate provides against disastrous results which would otherwise be inevitable.

[Footnote 1: For this improvement Prof. Swenson obtained a patent Oct. 11, 1887, the grant of which was recently made the subject of congressional inquiry.]

Immediately after it is drawn from the diffusion battery the juice is taken from the measuring tanks into the defecating tanks or pans. These are large, deep vessels, provided with copper steam coils in the bottom for the purpose of heating the juice. Sufficient milk of lime is added here to nearly or quite neutralize the acids in the juice, the test being made with litmus paper. The juice is brought to the boiling point, and as much of the scum is removed as can be taken quickly. The scum is returned to the diffusion cells, and the juice is sent by a pump to the top of the building, where it is boiled and thoroughly skimmed. These skimmings are also returned to the diffusion cells.

This method of disposing of the skimmings was suggested by Mr. Parkinson. It is better than the old plan of throwing them away to decompose and create a stench about the factory. Probably a better method would be to pass these skimmings through some sort of filter, or, perhaps better still, to filter the juice and avoid all skimming. After this last skimming the juice is ready to be boiled down to a thin sirup in

THE DOUBLE EFFECT EVAPORATORS.

These consist of two large closed pans provided within with steam pipes of copper, whereby the liquid is heated. They are also connected with each other and with pumps in such a way as to reduce the pressure in the first to about three fifths and in the second to about one fifth the normal atmospheric pressure.

The juice boils rapidly in the first at somewhat below the temperature of boiling water, and in the second at a still lower temperature. The exhaust steam from the engines is used for heating the first pan, and the vapor from the boiling juice in the first pan is hot enough to do all the boiling in the second, and is taken into the copper pipes of the second for this purpose. In this way the evaporation is effected without so great expenditure of fuel as is necessary in open pans, or in single effect vacuum pans, and the deleterious influences of long continued high temperature on the crystallizing powers of the sugar are avoided.

From the double effects the sirup is stored in tanks ready to be taken into the strike pan, where the sugar is crystallized.

THE FIRST CHANCE TO PAUSE.

At this point the juice has just reached a condition in which it will keep. From the moment the cane is cut in the fields until now, every delay is liable to entail loss of sugar by inversion. After the water is put into the cells of the battery with the chips, the temperature is carefully kept above that at which fermentation takes place most readily, and the danger of inversion is thereby reduced. But with all the precautions known to science up to this point the utmost celerity is necessary to secure the best results. There is here, however, a natural division in the process of sugar making, which will be further considered under the heading of "Auxiliary Factories." Any part of the process heretofore described may be learned in a few days by workmen of intelligence and observation who will give careful attention to their respective duties.

BOILING THE SIRUP TO GRAIN THE SUGAR.

This operation is the next in course, and is performed in what is known at the sugar factory as the strike pan, a large air tight iron vessel from which the air and vapor are almost exhausted by means of a suitable pump and condensing apparatus. As is the case with the saccharine juices of other plants, the sugar from sorghum crystallizes best at medium temperature.

The process of boiling to grain may be described as follows: A portion of the sirup is taken into the pan, and boiled rapidly in vacuo to the crystallizing density. If in a sirup the molecules of sugar are brought sufficiently near to each other through concentration—the removal of the dissolving liquid—these molecules attract each other so strongly as to overcome the separating power of the solvent, and they unite to form crystals. Sugar is much more soluble at high than at low temperatures, the heat acting in this as in almost all cases as a repulsive force among the molecules. It is therefore necessary to maintain a high vacuum in order to boil at a low temperature, in boiling to grain. When the proper density is reached the crystals sometimes fail to appear, and a fresh portion of cold sirup is allowed to enter the pan. This must not be sufficient in amount to reduce the density of the contents of the pan below that at which crystallization may take place. This cold sirup causes a sudden though slight reduction in temperature, which may so reduce the repulsive forces as to allow the attraction among the molecules to prevail, resulting in the inception of crystallization. To discover this requires the keenest observation. When beginning to form, the crystals are too minute to show either form or size, even when viewed through a strong magnifying glass. There is to be seen simply a very delicate cloud. The inexperienced observer would entirely overlook this cloud, his attention probably being directed to some curious globular and annular objects, which I have nowhere seen explained. Very soon after the sample from the pan is placed upon glass for observation, the surface becomes cooled and somewhat hardened. As the cooling proceeds below the surface, contraction ensues, and consequently a wrinkling of the surface, causing a shimmer of the light in a very attractive manner. This, too, is likely to attract more attention than the delicate, thin cloud of crystals, and may be even confounded with the reflection and refraction of light, by which alone the minute crystals are determined. The practical operator learns to disregard all other attractions, and to look for the cloud and its peculiarities. When the contents of the pan have again reached the proper density, another portion of sirup is added. The sugar which this contains is attracted to the crystals already formed, and goes to enlarge these rather than to form new crystals, provided the first are sufficiently numerous to receive the sugar as rapidly as it can crystallize.

The contents of the pan are repeatedly brought to the proper density, and fresh sirup added as above described until the desired size of grain is obtained, or until the pan is full. Good management should bring about these two conditions at the same time. If a sufficient number of crystals has not been started at the beginning of the operation to receive the sugar from the sirup added, a fresh crop of crystals will be started at such time as the crystallization becomes too rapid to be accommodated on the surfaces of the grain already formed. The older and larger crystals grow more rapidly, by reason of their greater attractive force, than the newer and smaller ones on succeeding additions of sirup, so that the disparity in size will increase as the work proceeds. This condition is by all means to be avoided, since it entails serious difficulties on the process of separating the sugar from the molasses. In case this second crop of crystals, called "false grain" or "mush sugar" has appeared, the sugar boiler must act upon his judgment, guided by his experience as to what is to be done. He may take enough thin sirup into the pan to dissolve all of the crystals and begin again, or, if very skillful, he may so force the growth of the false grain as to bring it up to a size that can be worked.

The completion of the work in the strike pan leaves the sugar mixed with molasses. This mixture is called malada or masscuite. It may be drawn off into iron sugar wagons and set in the hot room above mentioned, in which case still more of the sugar which remains in the uncrystallized state generally joins the crystals, somewhat increasing the yield of "first sugars." At the proper time these sugar wagons are emptied into a mixing machine, where the mass is brought to a uniform consistency. If the sugar wagons are not used, the strike pan is emptied directly into the mixer.

THE CENTRIFUGAL MACHINES.

From the mixer the melada is drawn into the centrifugal machines. These consist, first, of an iron case resembling in form the husk of mill stones. A spout at the bottom of the husk connects with a molasses tank. Within this husk is placed a metallic vessel with perforated sides. This vessel is either mounted or hung on a vertical axis, and is lined with wire cloth. Having taken a proper portion of the melada into the centrifugal, the operator starts it to revolving, and by means of a friction clutch makes such connection with the engine as gives it about 1,500 revolutions per minute. The centrifugal force developed drives the liquid molasses through the meshes of the wire cloth, and out against the husk, from which it flows off into a tank. The sugar, being solid, is retained by the wire cloth. If there is in the melada the "false grain" already mentioned, it passes into the meshes of the wire cloth, and prevents the passage of the molasses. After the molasses has been nearly all thrown out, a small quantity of water is sprayed over the sugar while the centrifugal is in motion. This is forced through the sugar, and carries with it much of the molasses which would otherwise adhere to the sugar, and discolor it. If the sugar is to be refined, this washing with water is omitted. When the sugar has been sufficiently dried, the machine is stopped, the sugar taken out, and put into barrels for market.

Simple as the operation of the centrifugals is, the direction of the sugar boiler as to the special treatment of each strike is necessary, since he, better than any one else, knows what difficulties are to be expected on account of the condition in which the melada left the strike pan.

CAPACITY OF THE SUGAR FACTORY.

A plant having a battery like that at Fort Scott, in which the cells are each capable of containing a ton of cane chips, should have a capacity of 180 tons of cleaned cane, or 200 tons of cane with leaves, or 240 tons of cane as it grows in the field, per day of twenty-four hours. Those who have given most attention to the subject think that a battery composed of one and a half ton cells may be operated quite as successfully as a battery of one ton cells. Such a battery would have a capacity of 360 tons of field cane per day.

THE CUTTING AND CLEANING APPARATUS.

This consists of modifications of appliances which have long been used. Simple as it is, and presenting only mechanical problems, the cutting, cleaning, and evaporating apparatus is likely to be the source of more delays and perplexities in the operation of the sugar factory than any other part.

The diffusion battery in good hands works perfectly; the clarification of the juice causes no delays; the concentration to the condition of semi-sirup may be readily, rapidly, and surely effected in apparatus which has been brought to great perfection by long experience, and in many forms; the work at the strike pan requires only to be placed in the hands of an expert; the mixer never fails to do its duty; there are various forms of centrifugal machines on the market, some of which are nearly perfect. If, then, the mechanical work of delivering, cutting, cleaning, and elevating the cane can be accomplished with regularity and rapidity, the operation of a well adjusted sugar factory should proceed without interruption or delay from Monday morning to Saturday night.

THE FUTURE OF THE SORGHUM SUGAR INDUSTRY.

An acre of land cultivated in sorghum yields a greater tonnage of valuable products than in any other crop, with the possible exception of hay. Under ordinary methods of cultivation, ten tons of cleaned cane per acre is somewhat above the average, but under the best cultivation the larger varieties often exceed twelve, while the small early amber sometimes goes below eight tons per acre. Let seven and a half tons of cleaned cane per acre be assumed for the illustration. This corresponds to a gross yield of ten tons for the farmer, and at two dollars per ton gives him twenty dollars per acre for his crop. These seven and a half tons of clean cane will yield:

750 pounds of sugar. 1,000 pounds of molasses. 900 pounds of seed. 1,500 pounds of fodder (green leaves). 1,500 pounds of exhausted chips (dried). A total of 5,650 pounds.

The first three items, which are as likely to be transported as wheat or corn, aggregate 2,650 pounds per acre.

Sorghum will yield seven and a half tons of cleaned cane per acre more surely than corn will yield thirty bushels or wheat fifteen bushels per acre.

In the comparison, then, of products which bear transportation, these crops stand as follows:

Sorghum, at 71/2 tons, 2,650 pounds per acre. Corn, at 30 bushels, 1,680 pounds per acre. Wheat, at 15 bushels, 900 pounds per acre.

The sugar from the sorghum is worth say 5 cents per pound; the molasses, 13/4 cents per pound; the seed, 1/2 cent per pound.

The sorghum products give market values as follows:

750 pounds sugar at say 5 cents,[2] $37.50. 1,000 pounds molasses at say 13/4 cents,[2] $17.50. 900 pounds seed at say 1/2 cent,[2] $4.50. Total value of sorghum, less fodder, $59.50. The corn crop gives 1,680 pounds, at 1/2 cent $8.40. The wheat crop gives 900 pounds, at 1 cent, $9.

[Footnote 2: The sugar sold this year at 53/4 cents per pound, the molasses at 20 cents per gallon, and the seed at —— per bushel of 56 pounds. The seed is of about equal value with corn for feeding stock.]

Thus it will be seen that the sorghum yields to the farmer more than twice as much per acre as either of the leading cereals, and as a gross product of agriculture and manufacture on our own soil more than six times as much per acre as is usually realized from either of these standard crops.

* * * * *

A new process for producing iron and steel direct from the ore has been brought out in Russia. Under the new process iron ore, after being submitted to the smelting processes, is taken direct from the furnace to the rolling mill and turned into thin sheets of the finest charcoal iron. At present the process has only been commercially applied with charcoal fuel, but experiments are stated to have shown that equal success can be obtained with coke. The secret of the process lies in the construction of the furnace, which is said to be simple and inexpensive.

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THE MENGES THERMO-MAGNETIC GENERATOR AND MOTOR.

We have received from M. Menges (of the Hague) a most interesting description of an apparatus on which he has been at work for some time past, with the object of generating electricity by the direct conversion of heat, or, as it might be more accurately described, by a more direct conversion than that of an ordinary dynamo. M. Menges' apparatus depends, like that of Edison, upon the fact that the magnetic metals lose their magnetic permeability at a certain temperature.

It differs greatly, however, from its predecessor in important points, especially in the fact that it does not require the aid of any external source of motive power.

In Edison's pyromagnetic dynamo it will be remembered that it is necessary to provide some small amount of motive power from an extraneous source in order to revolve the shield by which the heat is alternately directed on one half or the other of the armature cores. M. Menges' apparatus is, on the contrary, wholly automatic.

We proceed to give a free translation of the description furnished us by the inventor.

In attempting to employ the thermo-magnetic properties of iron or nickel in the construction of machines for the generation of electricity upon an industrial scale, we are met with the difficulty that the heating and cooling of large masses of metal not only involves great loss of heat, but also requires much time. Hence, to obtain a useful effect of any importance, it would appear necessary to employ machines of dimensions altogether impracticable. By the device and method of construction now to be explained this difficulty has, however, been completely overcome.

The action of a magnetic pole diminishes so rapidly with the increase of distance that it may suffice to remove the armature to a distance relatively small compared with its own dimensions, or with those of the magnet, in order to reduce the action to a negligible value. But if the magnet, N S, and the armature, A, being at a certain distance, we bring between them a piece of iron or nickel, d, then the magnetic force upon A is immediately and very considerably increased. In modern language, the resistance of the magnetic circuit has been reduced by the introduction of a better magnetic conductor, and the number of lines of force passing through A is proportionately increased. The mass of the piece, d, may, moreover, be relatively small compared with that of N S and A. If d be again withdrawn, the magnetic resistance is increased, and the lines through A are again a minimum.

Now, it is evident that we can also obtain the same effect by sufficiently heating and cooling the intermediate piece, d; and again, with a broad field we can alter the distribution of the lines at will by heating or cooling one side of this piece or the other. For this reason we will call the piece d the thermo-magnetic distributor, or, briefly, the distributor.

We will now describe the manner in which this principle has been realized in the practical construction of both a thermo-magnetic generator and motor.



Fig. 1 shows an elevation and part section of one of the arrangements employed. Fig. 2 is a plan of the same machine (in the latter the ring, a a, appearing on a higher plane than it actually occupies).



N S is an electro-magnet, a a the armature, wound as a Gramme ring, and fixed to a frame with four arms, which can turn freely upon a pivot midway between the poles. The cross arms of the frame are attached at 1, 2, 3, 4, Fig. 2. Between the magnets and the armature is placed the distributor, d d, where it occupies an annular space open above and below. Both the magnets and the armature are coated on the sides facing the distributor with mica or some other non-conductor of heat and electricity. The distributor is attached to and supported by the cross arms, so that it turns with the armature.

The distributor is composed of a ribbon of iron or nickel, bent into a continuous zigzag. This form has the advantage of presenting, in the cool part of the distributor, an almost direct road for the lines of force between the poles and the armature, thus diminishing the magnetic resistance as far as possible. At the same time the Foucault currents are minimized. To the same end it is useful to slit the ribbon, as in Fig. 3. This also facilitates the folding into zigzags.



The distributor is heated at two opposite points on a diameter by the burners, b b, above which are the chimneys, e e. The cooling of the alternate section is aided by the circulation of cold air, which is effected by means of the draught in the chimneys, e e. At the points of lowest temperature a jet of air or water is maintained. The cross arms are insulated with mica or asbestos at the points where they extend from the armature to the distributor.

It will now be evident that while the distributor is entirely cool, many of the lines of force pass from N to S without entering the armature core; but if heat is applied at the points 1 and 2 in the figure, so as to increase the magnetic resistance at these points, then a great portion of the lines will leave the distributor, and pass through the armature core. Under these conditions, so long as heat is applied at two points equidistant from N and S, we might, if we so pleased, cause the armature to be rotated by an external source of power, and we should then have an E.M.F. generated in the armature coils—that is to say, the machine would work as an ordinary dynamo, and the power expended in driving the armature would be proportionate to the output.

Suppose next that the points of heating, and with them the alternate points of cooling 90 deg. apart, are shifted round about 45 deg., so that the two hot regions are no longer symmetrically situated in respect to each pole of the field. The distribution of the magnetization has therefore become unsymmetrical, and the iron core is no longer in equilibrium in the magnetic field. We have, in fact, the conditions of Schwedoff's experiment upon a larger scale, and if the forces are sufficient to overcome the frictional resistance, a rotation of the ring ensues in the endeavor to restore equilibrium. The regions of heating and cooling being fixed in space, this rotation is continuous so long as the difference of temperature is maintained. The ring in rotating carries with it the armature coils, and of course an E.M.F. is generated in the same way as if the motive power came from an external source. In this respect the machine therefore resembles a motor generator, and the rotation is entirely automatic.

The armature coils are connected with a commutator in the usual way, and the field may, of course, be excited either in shunt or in series. M. Menges says that the residual magnetization is sufficient in his machine to start the rotation by itself.

When the machine is to be used as a motor, it is evident that the windings on the armature core need only be sufficient to supply current to excite the field, or by the use of permanent magnets they may be dispensed with altogether.

M. Menges has further designed a large number of variations on the original type, varying the arrangement of the several parts, and employing armatures and fields of many different types, such as are already in use for dynamos.

In Fig. 4 a machine is represented in which the field is external to the armature.



In Fig. 5 we have a thermo-magnetic generator, which corresponds to the disk machine in dynamos. Similar parts are indicated by the same letters in each of these figures, so that no further detailed description is necessary.



In another modification M. Menges proposes to rotate the burners and leave the armature and distributor at rest. But in this case it is evident that the E.M.F. produced would be much less, because the magnetization of the core would only undergo a variation of intensity, and would nowhere be reversed, except, perhaps, just in front of the poles. In machines modeled on the Brush type it is evident that the distributor need not be continuous.

Enough has, however, been said to indicate the extent of the field upon which the principle may be applied.—The Electrician.

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OBSERVATIONS ON ATMOSPHERIC ELECTRICITY.[1]

[Footnote 1: Abstract of a paper read before the British Association meeting at Manchester, September, 1887.]

BY PROF. L. WEBER.

I will try to give a short report of some experiments I have made during the last year in regard to atmospheric electricity. It was formerly uncertain whether the electrostatic potential would increase by rising from the surface of the earth to more elevated region of the atmosphere or not, and also whether the potential in a normal—that is, cloudless—state of the atmosphere was always positive or sometimes negative. Sir William Thomson found by exact methods of measuring that the increase of the potential with elevation is very important, and values about 100 volts per meter. That fact is proved by many other observers, especially lately by Mr. F. Exner, at Vienna, who found an increase of 60 to 600 volts per meter. The observations were made by means of an electrometer. In respect of many inconveniences which are connected with the use of an electrometer, I have tried the measurements with a very sensitive galvanometer. In this case it is necessary to apply a separating air exhaust apparatus, for example flame, or a system of points at the upper end of the conductor, which is elevated in the atmosphere. In order to get a constant apparatus, I have used 400 of the finest needles inserted in a metallic ribbon. This system I have raised in the air by means of a captive balloon, or by a kite, which was attached to a conductor of twine or to a twisted line of the finest steel wire. In this way I have attained a height of 100 to 300 meters. When the lower end of the kite line was communicating with the galvanometer whose other terminal was in contact with the earth, a current passed through the galvanometer. For determining the strength of this current I proposed to called a micro-ampere the 10^{-9} part of an ampere. At the height of about 100 meters in the average the current begins to be regular, and increases at the height of 300 meters to 4,000 or 5,000 of these units. The increase is very regular, and seems to be a linear function of the height. I have, nevertheless, found the smallest quantities of dust contained in the atmosphere or the lightest veil of cirrus disturbed the measurement very materially, and generally made the potential lower. In negative experiments of this nature I have made at Breslau, at the Sohneekoppe, and at the "Reisengebirge," especially at the last station, an increase of potential was observed, not only by reason of the perpendicular height, but also by reaching such regions of the atmosphere as were situated horizontally to about 200 meters from the utmost steep of the same mountain, Sohneekoppe. Therefore it must, according to Mr. Exner, be assumed that the surface of the air presents a surface of equal potential, and that the falling surfaces of high potential were stretched parallel over the plane contours of the air, and more thinly or narrow lying over all the elevated points, as, for example, mountains, church towers, etc. On the basis of these facts I think it easy to explain the electricity of thunder storm clouds, in fact every cloud, or every part of a cloud, may be considered as a leading conductor, such clouds as have for the most part perpendicular height. After being induced the change results by supposing the conduction of electricity either from the upper or from the lower side, according to greater or smaller speed of the air in the height. In the first case the clouds will be charged positive, in the other negative. I am inclined, therefore, to state that the electricity of thunder storm clouds must be considered as a special but disturbed case of the normal electric state of the atmosphere, and that all attempts to explain thunder storm electricity must be based on the study of the normal electric state of the atmosphere.

* * * * *



LINNAEUS.[1]

[Footnote 1: For the illustrations and many facts in the life of Linnaeus we are indebted to the Illustrated Tidning, Stockholm.]

BY C.S. HALLBERG.

At intervals in the history of science, long periods of comparative inertia have attended the death of its more distinguished workers. As time progresses and the number of workers increases, there is a corresponding increase in the number of men whose labors merit distinction in the literature of every language; but as these accessions necessitate in most cases further division of the honors, many names conspicuously identified with modern science fail of their just relative rank, and fade into unmerited obscurity. Thus the earlier workers in science, like Scheele, Liebig, Humboldt, and others of that and later periods, have won imperishable fame, to which we all delight to pay homage, while others of more recent times, whose contributions have perhaps been equally valuable for their respective periods, are given stinted recognition of their services, if indeed their names are not quite forgotten. Nothing illustrates so clearly the steps in the evolution of science as a review of the relative status of its representatives. As in the political history of the world an epoch like that of the French revolution stands out like a mountain peak, so in the history of science an epoch occurs rather by evolution than revolution, when a hitherto chaotic, heterogeneous mass of knowledge is rapidly given shape and systematized. Previous to the seventeenth century an immense mass of facts had accumulated through the labors of investigators working under the Baconian philosophy, but these facts had been thrown together in a confused, unsystematic manner. A man of master mind was then needed to grasp the wonders of nature and formulate the existing knowledge of them into a scientific system with a natural basis. Such a system was given by Linnaeus, and so great were its merits that it continues the foundation of all existing systems of classification.

Charles Linnaeus was born May 13, 1707, in a country place named Roshult in Smaland, near Skane, Sweden. He was called Charles after the well known Swedish knight errant, King Charles XII., then at the height of his renown.

The natural beauty of his native place, with its verdure-clad hills, its stately trees, and sparkling brooks fringed with mosses and flowers, inspired the boy Linnaeus with a love of nature and a devotion to her teachings which tinged the current of his whole life. He was destined by his parents for the ministry, and in accordance with their wish was sent to the Vexio Academy ("gymnasium"). Here the dull theological studies interfered so much with his study of nature that he would have felt lost but for the sympathy of Dr. Rothman, one of his teachers, a graduate of Harderwyk University, Holland, who had been a pupil of Boerhaave (the most eminent physician and scientist of his day), and been much impressed by his scientific teachings.



Dr. Rothman took a great interest in Linnaeus, and assured his father that he would prove a great success financially and otherwise as a physician (an occupation whose duties then included a study of all existing sciences). The father was satisfied, but dreaded the effect the announcement of such a career would have on the mother, whose ambition had been to see her son's name among the long list of clergymen of the family who had been ministers to the neighboring church of Stentrohult. She finally yielded, and the best possible use was made by Linnaeus of Dr. Rothman's tuition. Latin, then the mother tongue of all scientists and scholars, he wrote and spoke fluently.

At the age of twenty Linnaeus entered the University of Lund, and remained there a year. Here he formed the acquaintance of a medical man, a teacher in the university, who opened his home and his library to him, and took him on his botanical excursions and professional visits. Some time later, on Dr. Rothman's advice, Linnaeus entered the University of Upsala, then the most celebrated university of Northern Europe. His parents were able to spare him but one hundred silver thalers for his expenses. At the end of a year his money was spent, his clothing and shoes were worn out, and he was without prospects of obtaining a scholarship. When things were at their gloomiest he accidentally entered into a discussion with a stranger in the botanical garden, who turned out to be a clergyman scientist named Celsius. Celsius, while staying at Upsala, had conceived the plan of given a botanical description of biblical plants. Having learned that Linnaeus had a herbarium of 600 plants, he took the young man under his protection, and opened up to him his home and library.

While studying in this library, his observations regarding the sexes in plants, hitherto in a chaotic state, took form, stimulated by an abstract published in a German journal of Vaillant's views, and before the end of 1729 the basis of the sexual system had appeared in manuscript. This treatise having been seen by a member of the university faculty, Linnaeus was invited to fill a temporary vacancy, and lectured with great success therein one and a half years. Meanwhile the foundation of the celebrated treatises afterward published on the sexual system of classification and on plant nomenclature had been laid.

As in the history of most great men, a seemingly great misfortune proved to be a turning point in his career. The position he had temporarily filled with such credit to himself and profit to the students was claimed by its regular occupant, and, despite the opposition of the faculty, Linnaeus had to relinquish it. The two subsequent years were spent in botanical investigations under the patronage of various eminent men. During one of these he traveled through Lapland to the shores of the Polar Sea, and the results of this expedition were embodied in his "Lapland Flora," the first flora founded on the sexual system. He delivered a peripatetic course of lectures, and during one of these he formed the acquaintance of Dr. Moraeus, a pupil of the great Boerhaave. Dr. Moraeus took Linnaeus into partnership with him. Here again a seeming misfortune proved to be a great advantage. Linnaeus fell in love with the eldest daughter of Dr. Moraeus, but was denied her hand until he should graduate in medicine. Linnaeus, to complete his studies as a physician, then entered the University of Harderwyk, Holland, the alma mater of his first benefactor, Dr. Rothman, and of the great Boerhaave.

After two years' study he was graduated in medicine with high honors. His thesis, "The Cause of Chills," received special commendation. He visited all the botanical gardens and other scientific institutions for which Holland was then renowned. A learned and wealthy burgomaster, Gronovius, having read his "Systema Naturae" in manuscript, not only defrayed the cost of its publication, but secured him the high honor of an interview with the great Boerhaave—an honor for which even the Czar Peter the Great had to beg.

Boerhaave's interest was at once awakened, and he gave Linnaeus so strong a recommendation to Dr. Burman, of Amsterdam, that the influence of the scientific circles of the Dutch metropolis was exerted in behalf of Linnaeus, and he was soon offered the position of physician superintendent of a magnificent botanical garden owned by a millionaire horticultural enthusiast, Clifford, a director of the Dutch East India Company. Linnaeus' financial and scientific future was now secure. Publication of his works was insured, and his position afforded him every opportunity for botanical research. After five years' residence in Holland, during which he declined several positions of trust, he determined to return to Sweden. His fame had become so widespread in Western Europe that his system was already adopted by scientists and made the basis of lectures at the Dutch universities. In the French metropolis he was greatly esteemed, and during a visit thereto he was a highly distinguished guest.



His reception in Sweden was rather frigid, and but for the hearty welcome by his family and betrothed he would probably have returned to Holland. His amour propre was also doubtless wounded, and he determined to remain and fight his way into the magic circle of the gilt-edged aristocracy which then monopolized all scientific honors in Stockholm and the universities. He acquired a great reputation for the treatment of lung disease, and was popularly credited with the ability to cure consumption. This reached the ears of the queen (a sufferer from the disease), who directed one of her councilors to send for Linnaeus. He soon recognized the name of Linnaeus as one of great renown on the Continent, and at once took him under his protection.

The star of Linnaeus was now in the ascendant. He was soon delegated to various pleasant duties, among which was the delivery of lectures on botany and mineralogy in the "auditorium illustre" at Stockholm. He at this time founded the "Swedish Scientific Academy," and was its first president. In 1741 he was elected professor of medicine in Upsala University, which chair he exchanged for that of botany and the position of director of the botanical garden. This opened up a new era for science in Sweden. He who was regarded as the world's greatest botanist abroad had at last been similarly acknowledged in his native land.

With the indomitable courage and tact characteristic of the man, he set on foot a gigantic scientific popular educational project. The government, under his direction, established a system of exploring expeditions into the fauna, flora, and mineralogy of the whole Swedish peninsula, partly for the purpose of developing the resources of the country, partly in the interest of science, but more especially to interest the mass of the people in scientific research. The vast majority of the people of Sweden, like those of other countries, were dominated by fetichic superstitions and absurd notions about plants and vegetables, which were indorsed to a certain extent by popular handbooks devoted more to the dissemination of marvels than facts. A popular clergyman, for instance, stated in a description of the maritime provinces that "certain ducks grew upon trees." The vast stride which was made by the populace in the knowledge of nature was due to these efforts of Linnaeus, who, in order to further popularize science, established and edited, in conjunction with Salvius, a journal devoted to the discussion of natural history.

During this period, on the first of May, semi-weekly excursions were made from the university, the public being invited to attend. The people came to these excursions by hundreds, and all classes were represented in them—physicians, apothecaries, preachers, merchants, and mechanics, all joined the procession, which left the university at seven in the morning, to return at eve laden with zoological, botanical, and mineralogical specimens.

A man who could thus arouse popular enthusiasm for science a century and a half ago must have been a remarkable genius. Trusted students of Linnaeus were sent on botanical exploring expeditions throughout the world. The high renown in which Linnaeus was held was shown in the significant title, almost universally bestowed upon him, of "The Flower King."—Western Druggist.

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ON A METHOD OF MAKING THE WAVE LENGTH OF SODIUM LIGHT THE ACTUAL AND PRACTICAL STANDARD OF LENGTH.

BY ALBERT A. MICHELSON AND EDWARD W. MORLEY.

The first actual attempt to make the wave length of sodium light a standard of length was made by Peirce.[1] This method involves two distinct measurements: first, that of the angular displacement of the image of a slit by a diffraction grating, and, second, that of the distance between the lines of the grating. Both of these are subject to errors due to changes of temperature and to instrumental errors. The results of this work have not as yet been published; but it is not probable that the degree of accuracy attained is much greater than one part in fifty or a hundred thousand. More recently, Mr. Bell, of the Johns Hopkins University, using Rowland's gratings, has made a determination of the length of the wave of sodium light which is claimed to be accurate to one two hundred thousandth part[2]. If this claim is justified, it is probably very near the limit of accuracy of which the method admits. A short time before this, another method was proposed by Mace de Lepinay.[3] This consists in the calculation of the number of wave lengths between two surfaces of a cube of quartz. Besides the spectroscopic observations of Talbot's fringes, the method involves the measurement of the index of refraction and of the density of quartz, and it is not surprising that the degree of accuracy attained was only one in fifty thousand.

[Footnote 1: Nature, xx, 99, 1879; this Journal, III, xviii, 51, 1879.]

[Footnote 2: On the absolute wave lengths of light, this Journal, III, xxxiii, 167, 1887.]

[Footnote 3: Comptes Rendus, cii, 1153, 1886; Journal, de Phys., II, v, 411, 1886.]

Several years ago, a method suggested itself which seemed likely to furnish results much more accurate than either of the foregoing, and some preliminary experiments made in June have confirmed the anticipation. The apparatus for observing the interference phenomena is the same as that used in the experiments on the relative motion of the earth and the luminiferous ether.

Light from the source at s (Fig. 1), a sodium flame, falls on the plane parallel glass, a, and is divided, part going to the plane mirror, c, and part to the plane mirror, b. These two pencils are returned along cae and bae, and the interference of the two is observed in the telescope at e. If the distances, ac and ab, are made equal, the plane, c, made parallel with that of the image of b, and the compensating glass, d, interposed, the interference is at once seen. If the adjustment be exact, the whole field will be dark, since one pencil experiences external reflection and the other internal.

If now b be moved parallel with itself a measured distance by means of the micrometer screw, the number of alternations of light and darkness is exactly twice the number of wave lengths in the measured distance. Thus the determination consists absolutely of a measurement of a length and the counting of a number.

The degree of accuracy depends on the number of wave lengths which it is possible to count. Fizeau was unable to observe interference when the difference of path amounted to 50,000 wave lengths. It seemed probable that with a smaller density of sodium vapor this number might be increased, and the experiment was tried with metallic sodium in an exhausted tube provided with aluminum electrodes. It was found possible to increase this number to more than 200,000. Now it is very easy to estimate tenths or even twentieths of a wave length, which implies that it is possible to find the number of wave lengths in a given fixed distance between two planes with an error less than one part in two millions and probably one in ten millions. But the distance corresponding to 400,000 wave lengths is roughly a decimeter, and this cannot be determined or reproduced more accurately than say to one part in 500,000. So it would be necessary to increase this distance. This can be done by using the same instrument together with a comparer.

The intermediate standard decimeter, lm (Fig. 2), is put in place of the mirror, b. It consists of a prism of glass one decimeter long with one end, l, plane, and the other slightly convex, so that when it touches the plane, m, Newton's rings appear, and these serve to control any change in the distance, lm, which has been previously determined in wave lengths.

The end, l, is now adjusted so that colored fringes appear in white light. These can be measured to within one-twentieth of a wave length, and probably to within one-fiftieth. The piece, lm, is then moved forward till the fringes again appear at m. Then the refractometer is moved in the same direction till the fringes appear again at l, and so on till the whole meter has been stepped off. Supposing that in this operation the error in the setting of the fringes is always in the same direction, the whole error in stepping off the meter would be one part in two millions. By repetition this could of course be reduced. A microscope rigidly attached to the carriage holding the piece, lm, would serve to compare, and a diamond attached to the same piece would be used to produce copies. All measurements would be made with the apparatus surrounded by melting ice, so that no temperature corrections would be required.

Probably there would be considerable difficulty in actually counting 400,000 wave lengths, but this can be avoided by first counting the wave lengths and fractions in a length of one millimeter and using this to step off a centimeter. This will give the nearest whole number of wave lengths, and the fractions may be observed directly. The centimeter is then used in the same way to step off a decimeter, which again determines the nearest whole number, the fraction being observed directly as before.

The fractions are determined as follows: The fringes observed in the refractometer under the conditions above mentioned can readily be shown to be concentric circles. The center has the minimum intensity when the difference in the distances, ab, ac, is an exact number of wave lengths. The diameters of the consecutive circles vary as the square roots of the corresponding number of waves. Therefore, if x is the fraction of a wave length to be determined, and y the diameter of the first dark ring, d being the diameter of the ring corresponding to one wave length, then x = y squared/d squared.

[Illustration:

- - c - - l 2. m - - - / / - - a / / / / b S //d/ / / / / / - - - / : - m e : - : 1. U ]

There is a slight difficulty to be noted in consequence of the fact that there are two series of waves in sodium light. The result of this superposition of these is that as the difference of path increases, the interference becomes less distinct and finally disappears, reappears, and has a maximum of distinctness again, when the difference of path is an exact multiple of both wave lengths. Thus there is an alternation of distinct interference fringes with uniform illumination. If the length to be measured, the centimeter for instance, is such that the interference does not fall exactly at the maximum—to one side by, say, one-tenth the distance between two maxima, there would be an error of one-twentieth of a wave length requiring an arithmetical correction.

Among other substances tried in the preliminary experiments were thallium, lithium, and hydrogen. All of these gave interference up to fifty to one hundred thousand wave lengths, and could therefore all be used as checks on the determination with sodium. It may be noted that in case of the red hydrogen line, the interference phenomena disappeared at about 15,000 wave lengths, and again at about 45,000 wave lengths; so that the red hydrogen line must be a double line with the components about one-sixtieth as distant as the sodium lines.—Amer. Jour. Science.

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[RURAL NEW YORKER]



COLD STORAGE FOR POTATOES.

Upon this subject I am able to speak with the freedom habitually enjoyed by some voluminous agricultural writers—my imagination will not be hampered by my knowledge.

In debatable climates, like Ohio, Illinois, Kansas and southward, it is conceded that a great point would be gained by the discovery of some plan—not too expensive—that would make it safe to put away potatoes in the summer, as soon as ripe, so that they would go through the winter without sprouting and preserve their eating qualities till potatoes come again. As it is, digging must be deferred till late, for fear of rot; the fields of early varieties grow up with weeds after they are "laid by." In the spring a long interregnum is left between old potatoes fit to eat and the new crop, and the seed stock of the country loses much of its vigor through sprouting in cellars and pits. Most farmers have had occasion to notice the difference between the yield from crisp, unsprouted seed potatoes and that from the wilted, sprouted tubers so often used. Some years ago Professor Beal made a test of this difference. I speak from recollection, but think I am right in saying that, according to the published account which I saw, he found one sprouting of seed potatoes lowered the yield 10 per cent.; each additional sprouting still further reduced the crop, till finally there was no yield at all. Even a 10 per cent. shrinkage in all that portion of the annual potato crop grown from sprouted seed would result in an aggregate loss of millions of bushels. The question how to store potatoes and not have them sprout I have seen answered in the papers by recommending a "cold" cellar, of about 40 degrees temperature. If there are cellars that are cold in warm weather, without the use of some artificial process, I have not seen them. The temperature of well water is about 45 degrees only, and anybody knows how much colder a well is than a cellar. But the greatest difficulty comes in from the fact that potatoes are such a prolific source of heat in themselves.