Chapter VII: BIOLOGY, ETC.--The Varying Susceptibility of Plants and Animals to (2)

In mills of from three hundred to five hundred barrels capacity and still larger, the programme differs considerably from that I have sketched, the middlings being graded and handled with little, if any, returning, and are sized down on the smooth rolls, a much larger percentage of the work of flouring being done on millstones. For a three hundred barrel roller mill, the following plant is requisite: five double corrugated roller mills, five double smooth roller mills, three pairs of four foot burrs sixteen purifiers, four wire scalping reels, six feet long, one reel for the fifth break, one reel for low grade flour, eight chop reels, seven reels for flour from smooth rolls, three reels for the stone flour, two grading reels, three flour packers, and necessary cleaning machinery. The reels are eighteen feet thirty-two inches. The programme is necessarily more complicated.

When it comes to the machinery to be employed in making the reductions or breaks, the miller has several styles from which to choose. Which is best comes under the head of what I don't know, and moreover, of that which I have found no one else who does know. Each machine has its good points, and the mill owner must make his own decision as to which is best suited to his purpose. The main principles involved are to abrade the bran as little as possible while cleaning it thoroughly, and to make as little break flour, and as many middlings as possible, the latter to be made in such shape as to be the most easily purified. Regarding the difference between spring and winter wheat for gradual reduction milling, it may be stated something after this manner: Spring wheat has a thinner and more tender bran, makes more middlings because it is harder, and for the same reason the flour is more inclined to be coarse and granular. In milling with winter wheat, especially the better varieties, there will be more break flour made, the middlings will be finer with fewer bran specks, and the bran more easily cleaned, because it will stand harsher treatment. Winter wheat, moreover, requires more careful handling in making the breaks, not because of the bran, but to avoid breaking down the middlings, and making too much and too fine and soft break flour. In order to keep the flour sharp and granular, coarser cloths are used in bolting, and because the middlings are finer the bolting is not so free and a larger bolting surface is required. In milling either spring or winter wheat there should be ample purifying capacity, it being very unwise to limit the number of machines, so that any of them will be overtaxed. The day has gone by when one purifier will take care of all the middlings in the mill.

There is one point which is of much interest to mill owners who wish to change their mills over to the gradual reduction process, that is, how far they can utilize their present plan of milling machinery in making the change. Of course the cleaning machinery is the same In both cases, so are the elevators, conveyors, bolting chests, etc. But to use the millstone is a debatable question. After carefully considering the matter I have come to the conclusion that it has its place, and an important one at that, under the new regime, viz., that of reducing the finer purified middlings to flour. The reason for this lies in the peculiar construction of the wheat berry. If the interior of the berry were one solid mass of flour, needing only to be broken up to the requisite fineness, it could be done as well on the rolls. But instead of this, as is well known, the flour part of the berry is made up of a large number of granules or cells, the walls of which are cellular tissue, different from the bran in that it is soft and white instead of hard and dark colored. It is also fibrous to a certain extent, and when the fine middlings are passed between the rolls instead of breaking down and becoming finer, it has a tendency to cake up and flatten out, rendering the flour soft and flaky. It does not hurt the color, but it does hurt the strength. When the millstone is used in place of the roll the flour is of equally good color, and more round and granular. I know that in this the advocates of smooth rolls will differ from my conclusions, but I believe that the final outcome will be the use of millstones on the finer middlings, and in fact on all the middlings that are thoroughly freed from the germ.

It has been said that that which a man gives the most freely and receives with the worst grace is advice. I will, however, close with a little of the article which may not be wholly put of place. If you have a mill do not imagine that the addition of a few pairs of rolls, a purifier or two, and a little overhauling of bolting-chests, is going to make it a full-fledged Hungarian roller mill. If you are going to change an old mill or build a new one, do not take the counsel or follow the plans of every itinerant miller or millwright who claims to know all about gradual reduction. No matter what kind of a mill you want to build, go to some milling engineer who has a reputation for good work, tell him how large a mill you want, show him samples of the wheat it must use and the grades of flour it must make, and have him make a programme for the mill and plan the machinery to fit it. Then have the mill built to fit the machinery. When it starts follow the programme, whether it agrees with your preconceived notions or not, and the mill will, in ninety-nine cases out of one hundred, do good work.

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MACHINE FOR DOTTING TULLES AND OTHER LIGHT FABRICS.

Dotted or chenilled tulles are fabrics extensively used in the toilet of ladies, and the ornamentation of which has hitherto been done by the application to the tissue, by hand, either of chenille or of small circles previously cut out of velvet. This work, which naturally takes considerable time, greatly increases the cost price of the article.

A few trials at doing the work mechanically have been made, but without any practical outcome. The workwomen who do the dotting are paid at Lyons at the rate of 80 centimes per 100 dots; so that if we take tulle with dots counter-simpled 0.04 of an inch, which is the smallest quincunx used, and suppose that the tissue is 31 inches wide and that the daily maximum production is one yard, we find that 400 dots at 80 centimes per 100 = 3 francs and 20 centimes (about 63 cents), the cost of dotting per yard. It is true that the workwoman furnishes the velvet herself.

Mr. C. Ricanet, of Lyons, has recently invented a machine with which he effects mechanically the different operations of dotting, not only on tulles but also upon gauzes or any other light tissues whatever, such as those of cotton, silk, wool, etc. Aided by a talented mechanic, Mr. Ricanet has succeeded in constructing one of those masterpieces of wonderfully accurate mechanism of which the textile industry appears to have the monopoly--at least it is permissible to judge so from the remarkable inventions of Vaucanson, Jacquard, Philippe de Girard, Heilmann, and others.

The object of this new machine, then, which has been doing its wonderful work for a few days only, is to reproduce artificially chenille embroidered on light tissues, by mechanically cutting out and gluing small circles of velvet upon these fabrics.

For this purpose all kinds of velvet may be employed, and, in order to facilitate the cutting, they are previously coated on the reverse side with any glue or gum whatever, which gives the velvet a stiffness favorable to the action of the punch. To effect the object desired the apparatus has three successive operations to perform: first, cutting the circles; second, moistening; and third, fastening down the dots upon the tissue according to a definite order and spacing. The machine may be constructed upon any scale whatever, although at present it is only made for operating on pieces 31 inches wide, that being the normal width of dotted tulles. The quincuncial arrangement of the dots is effected by the punching, moistening, and fastening down of odd and even dots, combined with the forward movement of the tissue to be chenilled.

The principal part of the machine is the cam-shaft, A (Figs. 1, 2, and 3), which revolves in the direction of the arrows and passes in the center of 80 cam-wheels, 40 of which are odd and 40 even, alternately opposed to each other. This shaft actuates, through its two extremities, the different combined motions in view of the final object to be attained, and also carries the motive pulleys, PP'. Figs. 1 and 2 show the profile of two of these opposed cam-wheels--the arrangement by means of which two rows of dots (odd and even) are laid down upon the tissue during one revolution of the shaft or drum, A. Each of the wheels carries three cams (Figs. 1 and 3), the first, (_a_), corresponding to the punching; the second, (_a'_), to the moistening, and the third, (_a''_), to the gluing down of the dots.

The annexed figure, one-quarter actual size, shows in section the details of the cutting mechanism. To each cam-wheel there corresponds one punch, and the eighty punches are arranged side by side and parallel upon a shaft, B, a spring, _b_, holding them constantly against the circumference of the cam-wheels. In Fig. 2 only one of these details is shown. The punching arrangement consists of an ordinary punch, _c_, of variable diameter, screwed to the extremity of a tube, _d_, which is itself suspended from the end of the lever, _p_, but which can receive from it at the desired moment the pressure necessary to effect the cutting. The vertical position of these multiple tubes is insured by a guide, _e_, which is thoroughly indispensable. Through each of the tubes, _d_, there passes a plunger designed for expelling from the punch the piece that has been cut out of the velvet, and for gluing it down to the fabric. The two small springs, _b'_ and _b''_, tend continually to lift the tubes as well as the plunger. The whole mechanism is affixed to solid cast-iron frames, and the machine itself may be mounted on wooden supports or a metal frame.

The punching is effected on a bronze straight-edge, C, which slides in a cast-iron channel, D. This presents alternately, in its movement, entire and punctured spaces, the former for receiving the blow of the punch and the latter for allowing passage at the desired moment to the plunger as it goes to fasten the dots upon the tulle which is passing along underneath the channel, D. The punching is done primarily and principally by pressure, but, in order to facilitate the complete detachment of filaments which might retain the punched-out piece, the punch is likewise given at the same time a slight rotary motion, thus imitating mechanically what is performed by hand in the maneuver of all punches. This rotary motion is communicated to the punches by means of levers actuated by an eccentric, E, and which move the frame, _h_, whose bars engage with the horizontal lever, _g_, soldered to the tube, _d_, thus causing the latter at the very moment the punch descends to revolve from right to left. The forty punches in operation cause the frame to return to its initial position through the action of the springs, _b'_. We say forty, since the inventor, in principle, has admitted 80 punches, operating 40 as odd and 40 as even; obtaining in this way a dotting in a regular quincunx of one yard, that is to say, 80 dots arranged in two rows on a fabric 31 inches wide. But it is evident that a much larger quincunx may be had by putting in play only a half, a third, or a fourth of the punches, and causing the tulle and velvet to advance proportionally. For this purpose it is only necessary to unscrew the punches which are not to act, and to substitute for the ratchet wheel which controls the unrolling of the I tulle, another having a number of teeth proportioned to the desired spacing of the dots.

The punching having been executed, and the drum, A, continuing to revolve, the punches rise a little owing to the conformation of the cam-wheel, and through the action of the springs, _b_, and allow the moistener to move forward to dampen the little circles which remain at the orifice of the punches. The moistener or dampener is a sort of pad equal in length to the field of action of the punches, and is affixed to a cross-bar, F, which is connected at its two extremities with the levers, G, that are actuated by the cam-wheels, H. These cam-wheels, or eccentrics, H, which are mounted on the shaft of the drum, A, cause the moistener to move forward as soon as the punches rise after operating, and, when it arrives beneath the punches, the larger cams, _a_, of the cam-wheels, A, press the latter upon the pad and thus effect the dampening of the circles of velvet.

Immediately afterwards, the same eccentrics, H, acting on a lever, I, uncover the holes in the straight-edge, C, and the channel, D. The large cams, _a"_, of the wheel, A, then acting very powerfully upon the respective punches, cause these latter to pass through the orifices so that the extremity of each punch comes within about one twenty-fifth of an inch of the fabric to be dotted. In this passage of the tube, _d_, a small rod, _i_, connected by a lever with the plunger, _f_, is made to abut against the guide, _e_, thus causing the descent of the plunger to a sufficient degree to push the velvet "dot" out of the tube and to glue it upon the fabric. The manner in which these operations are performed being now well enough understood, let us for a moment examine the motions of the fabrics to be cut and dotted--the first being velvet or any other material, even metal (goldleaf, for example), and the second, the tulle.

The latter has but one motion, and that is in the direction of its length, while the velvet has, in addition to this same motion, another slight one from right to left in the direction of its width in order to diminish waste as much as possible.

The tulle to be dotted is first wound around a roller, R, from whence it passes over the glass guide-roller, R', and between the channel, D, and the table, T, to the roller, R", which is heated by steam.

The hot air which is radiated dries the dots, and from thence the fabric is taken up by other rollers or by any other method. The steam roller, R", carries at one of its extremities a ratchet wheel whose teeth vary in number according to the greater or less rapidity with which the tulle is unrolled. It is actuated by a lever which receives its motion from the eccentric, K.

In the table, T, there is a rectangular receptacle, _t_, containing rasped or powdered velvet for the purpose of forming a reverse of the dot. This powder attaches itself to the gum and imitates on the wrong side of the fabric a dot similar to that on the upper or right side. The velvet is wound upon the roller, _r_, and from thence passes under the guiding roller, _r'_, the punches, and the second roller, _r"_. These two latter rollers are solidly connected by a straight-edge fixed at the extremity of the lever, L, whose other end is in continuous correlation with the eccentric, M, which controls the lateral displacements; while the eccentric, O, actuates, by means of the screw, Q, and the ratchet-wheel, S, the longitudinal advance of the velvet. The eccentric, M, is fixed upon an axle, A', which carries a wheel, U, having teeth inclined with respect to its axis, and which derives its motion from the Archimedean screw, N, fixed at one of the extremities of the cam-shaft, A.

We have stated above that the maximum daily hand production of tulle dotted in quincunxes of 0.04 of an inch is about one yard. At the rate of 30 revolutions per minute, and for the same article as that just mentioned, this dotting machine is capable of producing, theoretically, 360 yards per 10 hours; but practically this production is reduced to about 250 yards, which, however, is sufficiently satisfactory.

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THE REPRODUCTION AND MULTIPLICATION OF NEGATIVES.

By ERNEST EDWARDS, B.A.

A question, relative to the subject of reproducing negatives, which was put at a meeting of one of your New York societies, prompts me to make a few remarks on the subject.

Among the numerous and widely diversified ramifications of our business (the Heliotype Printing Company) we have very often to reproduce and multiply negatives in both a direct and reversed form. Various methods for doing this have been tried, and I may here say that I am quite well aware of all the methods that have hitherto been suggested for the purpose, but that which I am to describe is the one to which preference has been given, and which is that known as the carbon process.

A sheet of carbonized paper or "tissue," having been sensitized by immersion in a bath of bichromate of potash, is dried in the dark and placed away for future use, although it is undesirable that it be kept for more than four or five days. This is placed in a printing frame in contact with the negative and exposed for a few minutes, after which it is immersed in water, squeegeed down upon a glass plate, and developed with warm water in the way so well known to carbon printers. The result is a transparency which, owing to having received a sufficient exposure, should show every detail of the negative. The nature of the tissue employed for such a purpose must be such as to give no strong contrasts, but everything reproduced with soft and fine gradation of tone.

The transparency thus obtained forms the _cliché_ by which the negatives are subsequently made; and a negative of any size may be obtained by the camera on wet or dry plates. The transparency must, of course, be pointed to the sky and the light transmitted through it, no other light being allowed to reach the lens except that which passes through the carbon transparency. Care must also be taken that the transparency is _uniformly_ lighted. If it is not possible to obtain a northern light, which is best, a reflector of white paper or card may be used which must be sufficiently large and placed at an angle of about forty-five degrees to the transparency.

If the repeated negative is to be of the same size as the original it may be readily produced by repeating the operation of printing on carbon tissue, using the transparency in place of the negative, or using a dry plate in place of the tissue. But on the whole I have satisfied myself that the best results are to be obtained by the first method. There is a greater softness in the latter method, but a greater character and similarity to the original in the former method. There is no doubt that the use of the carbon transparency removes the hardness and riffidness of the outlines peculiar to the older method of a collodion transparency, while with carbon as the medium it is difficult for any but the most experienced eye to distinguish the copy from the original.--_Photo Times._

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A NEW METHOD OF MAKING GELATINE EMULSION.

Since gelatine emulsion first came into use one of the greatest troubles in connection with the manufacture of it has been that of washing. According to the first methods the time taken for this part of the process was, I believe, about twenty-four hours. It was very much reduced and the ease of manufacture greatly facilitated by the methods now most generally used, and which were, I believe, first communicated by Messrs. Wratten and Wainright. I refer to those of precipitating with alcohol and of straining the emulsion, when set, through canvas, so as to divide it very finely. When the latter method is resorted to a comparatively short time is sufficient to wash it. This method, although a great improvement upon the older ones, yet leaves much to be desired, especially for those who are not in the habit of making emulsion regularly, but only an occasional batch. When the weather is at all warm it takes a long time for the emulsion to set, unless ice be used, and when once it is set the washing process is an exceedingly "messy" one unless the water be cooled with ice; and the amount of water taken up during washing is often so great that there is considerable difficulty in getting the emulsion to set on the plates. In fact, even in cold weather, it is not an easy process to conduct in the necessary near approach to total darkness.

Considerable suspicion has of late been thrown upon the thoroughness of the alcohol method, unless the emulsion has, previous to precipitation, been freed of the greater part of the soluble salts by washing; that is to say, it is doubtful whether the whole of the soluble salts can be eliminated by the process, and, therefore, unless in exceptionally hot weather, it would seem best not to trust to it, except as a further security against soluble bromide and nitrate after washing. Besides this, the consumption of alcohol is very large. Almost three times the amount of the emulsion precipitated is required, and this, even when methylated spirit is used, adds considerably to the expense. With a view of doing away with the washing altogether, or, rather, of washing of the silver bromide when not incorporated with the gelatine, several processes have been invented. By these silver bromide is obtained in a very fine state of division, ready to mix with gelatine and water in any proportion.

The best known of them is Captain Abney's very ingenious glycerine method, which seems to have been thoroughly successful in his hands, although it has not been in every one's. The silver bromide obtained by his process is not highly sensitive, and requires boiling with gelatine before it is in a fit state to make a rapid plate.

We have lately had described in these columns a method of obtaining bromide in a highly-sensitive state by means of the use of an acid, whereby, after emulsifying and boiling, the viscosity of the gelatine was destroyed, and the bromide in time deposited itself. During the late hot weather, when washing became almost impossible, I was led to cast about for some method of eliminating the soluble salts less tedious and "sloppy" than that of washing, more certain and less expensive than that of precipitating the whole of gelatine with alcohol, and which would take less time than the method of obtaining the bromide in a pure form.

My first idea was to make up the solutions used in emulsifying in a very concentrated form, and, after emulsifying, boiling, and allowing to cool, to add to the thin emulsion thus obtained gelatine to the amount of twenty grains to the ounce, and to precipitate this with alcohol, the rest of the gelatine required to make up the bulk being afterwards added, and the whole thoroughly incorporated by warming and shaking. I was thus successful in reducing the amount of alcohol required to one-third of what would be necessary if the whole of the emulsion were precipitated; but still I found that, if a reliable emulsion were required, the pellicle as formed had to be washed to free it from the last trace of soluble salts.

It now struck me that it might be possible to precipitate the bromide of silver direct from a very weak solution of gelatine, and obtain it in such a form that it might be filtered, washed, and in every way treated as an ordinary precipitate. I tried the following experiment. I took--

1. Silver nitrate....................... 200 grains
Water............................... 1½ ounce.
2. Ammonia bromide...................... 120 grains.
Water................................ 1½ ounce.
Gelatine............................. 12 grains.

I emulsified the two together in the usual way, allowed the whole to cool, and then poured the thin emulsion into about ten ounces of alcohol, stirring the while. As I had anticipated, a flocculent precipitate was formed, which settled to the bottom of the vessel in a few minutes. This was, in fact, sensitive bromide of silver mixed with a very small quantity of gelatine (about five per cent.), and could, I found, be treated in the same manner as a bromide precipitate from an aqueous solution; it might be washed, either by decantation or by filtration, easily dried, and doubtless could, when dry, be kept for an indefinite time, and be at any time used by mixing with gelatine and water in any proportion thought fit.

I found that a less amount of gelatine than four grains to the ounce was sufficient to carry the bromide down, while five grains to the ounce carried it down in something which I considered too near an approach to a plastic mass.

It will be noticed that in the experiments which I have described the emulsion had not been boiled, so that the sensitiveness of the bromide was probably not great. As the experiment was done in daylight it was of no practical use for making emulsion; but I have since made several batches in this manner and have found them most satisfactory.

When sensitiveness is sought by boiling I rind it necessary to add a small quantity of gelatine after boiling and before precipitating, as that which has been kept for some time at a high temperature seems to have lost the viscosity necessary to carry down the silver bromide in such a form that it can he easily separated from the alcohol and water.

The practical manner of making an emulsion by this method may be as follows. Make up the following mixtures:

I.
Silver nitrate...........................................400 grains.
Water..................................................... 3 ounces.

II.

Ammonia bromide..........................................240 grains.
Gelatine..................................................24 grains
Water..................................................... 3 ounces.
Hydrochloric acid enough to slightly acidify the solution.

III.
Gelatine................................................. 20 grains.
Water.................................................... ½ ounce.
IV.

Hard gelatine (say Nelson's X opaque,
or Mr. A. L. Henderson's)................................240 grains.
Soft gelatine (Nelson's No.1)........................... 240 grains.
Water.....................................................24 ounces.

Nos. II., III., and IV. are allowed to stand until the gelatine is softened. No. I is then warmed in a hock bottle until the gelatine is just melted, when No. II. is poured into it, a little at a time, with vigorous shaking, until the whole is emulsified. It is then transferred to an ordinary jelly can, which is placed in a saucepan half full of water over a ring Bunsen burner in the dark room, and boiled for half an hour. It is then allowed to cool to about 100° Fahr., when No. III. is added. The whole is then allowed to get quite cool, when it is poured, with stirring, into about one pint of methylated spirit. If it be wished the precipitate may now be filtered out and washed at once like an ordinary filtrate, but I prefer to allow it to settle, which it will do in about five minutes. The supernatant fluid is then gently poured off.

This fluid will have the appearance of still containing a considerable amount of the silver bromide; but if it be kept and filtered it will be seen that the quantity is really so small that it may be disregarded. We all know what an alarming quantity of silver seems to be going down the sink when we wash vessels to which a very small quantity of emulsion is adhering. If filtering be resorted to the liquid which comes through will be quite clear. This was somewhat unexpected by me, as, if an emulsion containing the whole of the gelatine be precipitated into alcohol in the usual way, the alcohol becomes milky with a substance which could not, I imagine, be filtered from it.

Two or three ounces of methylated spirit are now added to the vessel containing the silver bromide, and the latter well mixed with it. This makes the precipitate "firmer"--if such an expression be allowable--and this time it will sink to the bottom almost immediately after the stirring has ceased, and the alcohol may be poured off.

I consider that the bromide in this state is practically free from soluble salts, but it may be washed with one or two changes of water if desired.

No. IV. is now gently heated till the gelatine is melted and the precipitate mixed with it. It must be kept warm for some time, and shaken vigorously until all granularity has disappeared, This is, of course, ascertained by placing a drop of the emulsion on a piece of glass, and examining it. If it be wished to keep the bromide of silver for future use it may be placed on a piece of muslin stretched in the drying-box, when it will dry in a very short time; and, although I cannot speak from experience on this point, it will, I have no doubt, keep for an indefinite time so long as light is kept from it.

If it be desired the ammonio-nitrate method may be used instead of the boiling one, although in my hands it does not give such sensitiveness. If it be desired to use this method, solution Nos. I, II., and IV. are made up exactly as for the boiling method, except that No. II. is not acidified. Liquid ammonia is then poured with stirring into the silver solution, until it blackens and again clears. Emulsification is performed exactly as described above, but instead of boiling, the emulsion is kept at a temperature of about 100° Fahr. for half an hour, when it is poured into the alcohol, no addition of gelatine being previously made.

I think I may claim for the method which I have just described that it is less troublesome and more certain than either the ordinary washing method or the usual one of precipitating with alcohol, while it affords an easy method of making sensitive silver bromide in such a form that it can be more easily stored and afterwards manipulated than if it were in the form of pellicle. The whole of the soluble salts are eliminated, and also any gelatine which may have been destroyed in the cooking. The amount of alcohol used is comparatively small; in fact, to prepare silver bromide for a pint of emulsion very little more than a pint of methylated spirit is required. Besides this I do not think that I would be wrong in saying that the chance of green fog is reduced to a minimum.

Let me take this opportunity of thanking Captain Abney for his prompt reply to my question about the connection between the proportion of bromide to gelatine in emulsions, and the density of resulting images.--_W. K. Burton, in British Journal of Photography_.

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THE POTTERY AND PORCELAIN INDUSTRIES OF JAPAN.

Japanese chronicles claim that the first pottery was made in the year 660 B.C.; it was not, however, until the Christian era that the art made any considerable advances. In the year 1223 A.D., great improvements were made in manufacture and decoration of the ware. From that date to the sixteenth century the great potteries of Owari, Hizen, Mino, Kioto, Kaga, and Satsuma were established. The Rahn-Yaki, or crackled ware, was first made at Kioto, at the commencement of the sixteenth century. The best old Hizen ware, that which is still the most admired, was made at Arita Hizen, in 1580 to 1585; the old Satsuma dates from 1592. Consul-General Van Buren states that porcelain clays are found in nearly all parts of the country, and the different kinds are usually found in close proximity, and close to canals and rivers, which is of considerable advantage, as affording a means of transport. In all cases every variety of clay used in the manufacture of pottery is found in a natural state; there is no necessity to manufacture the quartzose or fusible clays as is done in other parts of the world, and which adds considerably to the cost of the ware. One of the peculiarities in the clay found in Japan is that it contains both the fusible and infusible materials in such proportions as to make a light, beautiful, translucent, and durable porcelain. At Arita, in Hizen, there is a clay found which contains 783/4 per cent, of silica, and l73/4 per cent, of alumina; from this clay is made the delicate, translucent eggshell ware, without the addition of any other matter. From an adjoining bluff a clay is taken which has 50 per cent, of silica, and 38 per cent, of alumina; from this the common porcelain is made.

Potter's clay is found in very large quantities in the provinces of Yamashiro, Hoki, Turoo Iyo, Hizen, Higo, Owari, Mikaera, Idyn, Musashi, and Mino. In the whole of Japan there are 283 localities where the clay is deposited; many of these only furnish inferior clays, but they are all fitted for use in some of the various kinds of pottery. These clays are thoroughly powdered by means of what is called "balance pounders," worked in some localities by water-power, but the work is often done by hand. The powder is then dried, and stored on boards or in flat boxes. This dough does not go through the process of fermentation. The shaping is almost exclusively done on the potter's wheel, which is set on a pivot working in a porcelain eye. As a rule, the wheel is turned by the potter himself, but in Hizen it is kept in motion by means of a band connected with its pivot and another wheel turned by a boy. In making dishes of other shape than round, a crude mould is sometimes used. After the clay has been shaped on the wheel, it is set away for drying, and usually in two or three days it is considered sufficiently dry for smoothing, which is done on the wheel with a sharp curved knife. The material is now made into "bisque," or biscuit, by a preliminary baking in small ovens, when it is ready for painting, if it is to be painted on the biscuit; if not, it is ready for the glazing. In either event it will then go to the large furnace for the final baking. The kilns for this purpose are always built on hill sides, and are joined together, increasing in size from the lower to the higher ones, and in number from four to twenty five; these kilns are so constructed that the draught is from the lowest one, in addition to which each kiln has its own firing place. The result of this construction is that the upper ones are by far the most heated, and the ware is arranged accordingly; that which requires the least baking, in the lower kiln, and that which requires the greatest heat, in the upper. These connecting kilns have the merit of being heat saving, but they are usually small and badly constructed, and the heat in none of them is uniform.

The glaze is made from the silicious clay and potash extracted from wood ashes. This potash is not a pure white, and this accounts for the dirty color usually to be observed in unpainted Japanese ware. In different districts the painting varies. For instance, in Owari, the greater part of the ware is painted a cobalt blue--the cobalt ore being found in the bluffs near the clay deposits, and is used for painting the cheaper wares, and for this purpose German cobalt is also employed. The painting with cobalt is generally done on the biscuit before glazing. In several districts a very handsome ware is made, and painted on the glaze. For this kind of painting the colors are mixed with a silicate of lead and potash, and baked the third time in a small furnace at a low temperature. The coloring oxides in use are those of copper, cobalt, iron, antimony, manganese, and gold. Japanese porcelain painting may be divided into two categories, decorative and graphic; the first is used to improve the vessel upon which it is placed, and this class includes all the ware except that of the province of Kaga, which would come under the head of graphic, as it delineates all the trades, occupations, sports, customs, and costumes of the people, as well as the scenery, flora, and fauna of the country. "Owari ware" is made in the province of that name; it is not as translucent, but stronger and more tenacious than some of the Hizen manufacture.

The principal potteries are at a village called Sèto, twelve miles from the sea; in this village there are more than 200 kilns. The ware is mostly painted a cobalt blue, and is merely of a decorative kind, consisting of branches of trees, grass, flowers, birds, and insects, all these being copied by the artist from nature. All the Owari ware is true hard porcelain, and is strong and durable. In Hizen, a number of wares are manufactured, the best known kind being the "Eurari," which is made at Arita, but painted at Eurari. The colors in use are red, blue, green, and gold; these are combined in various proportions, but, as a rule, the red predominates. Generally the surface of the vessel is divided into medallions of figures, which alternately have red, blue, or white back-ground, with figures in green or blue and gold.

The egg-shell porcelain sold at Nagasaki is made in this province from Arita clay, and this is made from clay with no admixture of fusible matter except that contained by the clay naturally. The province of Satsuma is noted for crackled ware. It is only within a very few years that large vases have been manufactured, and in earlier days the old ware was confined to small vessels. The glaze is a silicate of alumina and potash, and the best ware has a complete network of the finest crackles; the painting is of birds and flowers, and noted for its delicate lines of green, red, and gold.

In Kioto, the ware manufactured is very similar to that produced in Satsuma, but it is lighter and more porous; the decorations are also nearly the same, being of birds and flowers. There is a description of ware made in Kioto, called "Eraku," the whole body of which is covered with a red oxide of iron, and over this mythical figures of gold are traced. That produced in Kagja is _faïence_, and in the style of painting is unlike any other in Japan, the predominating color being a light red, used with green and gold. The designs with which it is profusely decorated are trees, grasses, flowers, birds, and figures of all classes of people, with their costumes, occupations, and pastimes. The "Banko" ware is made at the head of the Owari Bay; it is an unglazed stone-ware, very light and durable, made on moulds in irregular shapes, and decorated with figures in relief. On the island of Awadji, a delicate, creamy, crackled, soft paste porcelain is made. The figures used in decoration are birds and flowers, but outlined by heavy, dark lines.

Consul Van Buren is of opinion that, at no distant day, Japan will be one of the foremost competitors in the pottery markets of the world, on account of the great variety and excellence of the clays, their proximity to the sea, the cheapness of labor, and the beauty and originality of the decorations. Already this important industry has been greatly stimulated by the foreign demand, and by the success of Japanese exhibitors at the Exhibitions of Vienna, Philadelphia, and Paris.--_Journal of the Society of Arts_.

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Professor Julius E. Hilgard, for twenty years assistant in charge of the office, has been placed in temporary charge of the Coast and Geodetic Survey. It is understood that he will be appointed superintendent to succeed the late Captain Carlile P. Patterson.

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THE FRENCH CRYSTAL PALACE.

The first idea of the French Crystal Palace was suggested by the English structure of the same name at Sydenham, about eight miles from London. Such a structure, as may be readily conceived, requires a site of vast extent, and one that shall be easy of access and possess the most agreeable surroundings. To the promoter of the project, those portions of the park of St. Cloud in the vicinage of the old chateau appeared to combine within themselves all the conditions that were desirable, and he, therefore, on the 15th of December, 1879, addressed the Ministers of Public Works and of Finances asking for the necessary concessions. The extensive specifications have been finally completed and will probably be shortly submitted for the approval of the parliament. The moment has arrived then for the public press to take cognizance of a project which concerns so great interests.

At present we shall say a few words _à propos_ of the engraving we present herewith. The French Crystal Palace will consist of one great nave, two lateral naves, two surrounding galleries, and a vast rotunda behind. The principal entrance, located at the head of the avenue leading from the present ruins (which will, ere long, be transformed into a most interesting museum), will exhibit a very striking aspect with its monumental fountain and the dome which it is proposed to erect over the very entrance itself. The whole structure will cover about nineteen acres of ground, thus being two and a half times the extent of the Palace of Industry in the Champs Elysees. The great nave of honor will be nearly 1,650 ft. in length, 78 ft. in width, and 98 ft. in height. The dome will measure exactly 328 ft. in height, or 105 ft. more than the towers of Notre Dame. The structure, with the exception of basement and foundation, will be of glass and iron.

The project which we publish to-day has been studied and gotten up, according to the general plans and dimensions suggested by the promoter, by Mr. Dumoulin, the architect. We are informed that the builder is to be Mr. Alfred Hunnebelle, a contractor well known from the extensive works that he has executed, and who is president of the Syndical Chamber of Contractors of Paris.

Among the annexes of this palace we may note a "Palace of the Republic," to be built on the ruins and designed for illustrious or distinguished visitors, such as the President of the Republic, the Ministers, the Municipal Council of Paris, foreign delegates, etc.; a farm house for special exhibitions and a field for experiments; galleries, cottages, etc.

As for the programme, which embraces six divisions and numerous subdivisions, we are unable to give it at present for want of space; we need only say that it satisfies perfectly all the conditions of so vast an undertaking.

In the hands of the projector, Mr. Nicole, who is well known from his long experience in such matters, the exhibition will undoubtedly prove a success and be instrumental in adding prosperity to all French industries.

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THE GREAT HEAT OF THE SUN.--Prof. S. P. Langley has made the following calculation: A sunbeam one centimeter in section is found in the clear sky of the Alleghany Mountains to bring to the earth in one minute enough heat to warm one gramme of water by 1° C. It would, therefore, if concentrated upon a film of water 1/500th of a millimeter thick, 1 millimeter wide, and 10 millimeters long, raise it 83 1/3° in one second, provided all the heat could be maintained. And since the specific heat of platinum is only 0.0032 a strip of platinum of the same dimensions would, on a similar supposition, be warmed _in one second_ to 2,603° C.--a temperature sufficient to melt it!

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CHATEAU IN THE AEGEAN SEA.

From the site of this building, magnificent views are obtained over the island-dotted sea and the mainland of Asia Minor: but, "though every prospect pleases," it is a land of earthquakes, and unfortunately, the works at the chateau have been suspended, owing to the dreadful calamity which has recently fallen upon the district. The building is intended for the residence of an English lady of exalted rank. It is to be built of local white stone, the hall, staircase, etc., being lined and paved with marbles. The hall is a large apartment about 25 ft. high, with paneled ceiling, having galleries on two sides, giving access to the rooms surrounding it on first floor, and to the turret staircase leading to roofs, etc. With the exception of sanitary apparatus, painted windows, etc. (which will be supplied by English firms), the whole of the work will be executed by native labor. The architect is Mr. Edwin T. Hall, London.--_Building News_.

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ELECTRIC POWER.

Just now nothing save electricity is talked about in scientific circles. During the meeting of the British Association the greatest possible prominence was given to electrical questions and propositions The success of the electric light, the introduction of the Faure battery with a great flourish of trumpets, and the magnificent display of electrical instruments and machinery at Paris, have all operated to the same end. The daily press has taken the subject up, and journals which were nothing hitherto if not political, now indulge in magnificent rhapsodies concerning the future of electricity. Even eminent engineers, carried away by the intoxication of the moment, have not hesitated to say that the steam engine is doomed, and that its place will be taken by the electricity engine. In the midst of all this noise and clamor and blowing of personal trumpets, it is not easy to keep one's head clear, and mistakes may be made which will cause disappointment to many and retard the progress of electrical science. We confidently expect that electricity will prove a potent agent by and by in the hands of the speculator for extracting gold from the pockets of the public, and we write now to warn our readers in time, and to endeavor to clear the air of some of the mists with which it is obscured. There is, no doubt, a great future before electricity; but it is equally certain that electricity can never do many things which the half informed may be readily made to believe it will do. We propose here to say enough on this point to enlighten our readers, without troubling them with perplexing problems and speculations.

No one at this moment knows what electricity is; but for our present purpose we may regard it as a fluid, non-elastic, and without weight, and universally diffused through the universe. To judge by recently published statements, a large section of the reading public are taught that this fluid is a source of power, and that it may be made to do the work of coal. This is a delusion. So long as electricity remains in what we may call a normal state of repose, it is inert. Before _we can get any work out of electricity a somewhat greater amount of work must be done upon it_. If this fundamental and most important truth be kept in view it will not be easy to make a grave mistake in estimating the value of any of the numerous schemes for making electricity do work which will ere long be brought before the public. To render our meaning clearer, we may explain that in producing the electric light, for instance, a certain quantity of electricity passes in through one wire to the lamp, and precisely the same quantity passes out through the other wire, and on to the earth or return wire completing the circuit. Not only is the quantity the same, the velocity is also unchanged. But in going through the lamp the current has done something. It has overcome the resistance of the carbons, heated them to a dazzling white heat, and so performed work. In doing this the current of electricity has lost something. Led from the first lamp to a second, it is found powerless--if the first lamp be of sufficient size. What is it that the electricity has lost? It has parted with what electricians would term "potential," or the capacity for performing work. What this is precisely, or in what way the presence or absence of potential modifies the nature of the electric current, no one knows; but it is known that this potential can only be conferred on electricity by doing work on the electricity in the first instance. The analogy between electricity and a liquid like water will now be recognized. So long as the water is at rest, it is inert. If we pump it up to a height, we confer on it the equivalent of potential. We can let the water fall into the buckets of an overshot wheel. Its velocity leaving the tail race may be identical with that at which it left the supply trough to descend on the wheel. Its quantity will be the same. It will be in all respects unchanged, just as the current of electricity passing through a lamp is unchanged; but it has, nevertheless, lost something. It has parted with its potential--capacity for doing work--and it becomes once more inert. But the duty which it discharged in turning the mill wheel was somewhat less than the precise equivalent of the work done in pumping it up to a level with the top of the wheel. In the same way the electric current never can do work equal in amount to the work done on it in endowing it with potential.