what use are such refinements? I may reply, what use is there in trying to do anything the very best it can be done? If our investigation of nature's profound mysteries can be partially solved with good instrumental means, what is the result if we have better ones placed in our hands, and what, we ask, if the best are given to the physicist? We have only to compare the telescope of Galileo, the prism of Newton, the pile of Volta, and what was done with them, to the marvelous work of the telescope, spectroscope, and dynamo of to-day. But I must proceed. It will be recognized that in working with the spherometer, only the points in actual contact can be measured at one time, for you may see by Fig. 6 that the four points, a a a a, may all be normal to a true plane, and yet errors of depression, as at e, or elevation, as at b, exist between them, so that the instrument must be used over every available part of the surface if it is to be tested rigorously. As to how exact this method is I cannot say from actual experience, as in my work I have had recourse to other methods that I shall describe. I have already quoted you the words of Prof. Harkness. Dr. Hastings, whose practical as well as theoretical knowledge is of the most critical character, tells me that he considers it quite easy to measure to 1/80000 of an inch with the ordinary form of instrument. Here is a very fine spherometer that Dr. Hastings works with from time to time, and which he calls his standard spherometer. It is delicately made, its screw being 50 to the inch, or more exactly 0.01998 inch, or within 2/100000 of being 1/50 of an inch pitch. The principal screw has a point which is itself an independent screw, that was put in to investigate the errors of the main screw, but it was found that the error of this screw was not as much as the 0.00001 of an inch. The head is divided into two hundred parts, and by estimation can be read to 1/100000 of an inch. Its constants are known, and it may be understood that it would not do to handle it very roughly. I could dwell here longer on this fascinating subject, but must haste. I may add that if this spherometer is placed on a plate of glass and exact contact obtained, and then removed, and the hand held over the plate without touching it, the difference in the temperature of the glass and that of the hand would be sufficient to distort the surface enough to be readily recognized by the spherometer when replaced. Any one desiring to investigate this subject further will find it fully discussed in that splendid series of papers by Dr. Alfred Mayer on the minute measurements of modern science published in SCIENTIFIC AMERICAN SUPPLEMENTS, to which I was indebted years ago for most valuable information, as well as to most encouraging words from Prof. Thurston, whom you all so well and favorably know. I now invite your attention to the method for testing the flat surfaces on which Prof. Rowland rules the beautiful diffraction gratings now so well known over the scientific world, as also other plane surfaces for heliostats, etc., etc. I am now approaching the border land of what may be called the abstruse in science, in which I humbly acknowledge it would take a vast volume to contain all I don't know; yet I hope to make plain to you this most beautiful and accurate method, and for fear I may forget to give due credit, I will say that I am indebted to Dr. Hastings for it, with whom it was an original discovery, though he told me he afterward found it had been in use by Steinheil, the celebrated optician of Munich. The principle was discovered by the immortal Newton, and it shows how much can be made of the ordinary phenomena seen in our every-day life when placed in the hands of the investigator. We have all seen the beautiful play of colors on the soap bubble, or when the drop of oil spreads over the surface of the water. Place a lens of long curvature on a piece of plane polished glass, and, looking at it obliquely, a black central spot is seen with rings of various width and color surrounding it. If the lens is a true curve, and the glass beneath it a true plane, these rings of color will be perfectly concentric and arranged in regular decreasing intervals. This apparatus is known as Newton's color glass, because he not only measured the phenomena, but established the laws of the appearances presented. I will now endeavor to explain the general principle by which this phenomenon is utilized in the testing of plane surfaces. Suppose that we place on the lower plate, lenses of constantly increasing curvature until that curvature becomes nil, or in other words a true plane. The rings of color will constantly increase in width as the curvature of the lens increases, until at last one color alone is seen over the whole surface, provided, however, the same angle of observation be maintained, and provided further that the film of air between the glasses is of absolutely the same relative thickness throughout. I say the film of air, for I presume that it would be utterly impossible to exclude particles of dust so that absolute contact could take place. Early physicists maintained that absolute molecular contact was impossible, and that the central separation of the glasses in Newton's experiment was 1/250,000 of an inch, but Sir Wm. Thomson has shown that the separation is caused by shreds or particles of dust. However, if this separation is equal throughout, we have the phenomena as described; but if the dust particles are thicker under one side than the other, our phenomena will change to broad parallel bands as in Fig. 8, the broader the bands the nearer the absolute parallelism of the plates. In Fig. 7 let a and b represent the two plates we are testing. Rays of white light, c, falling upon the upper surface of plate a, are partially reflected off in the direction of rays d, but as these rays do not concern us now, I have not sketched them. Part of the light passes on through the upper plate, where it is bent out of its course somewhat, and, falling upon the lower surface of the upper plate, some of this light is again reflected toward the eye at d. As some of the light passes through the upper plate, and, passing through the film of air between the plates, falling on the upper surface of the lower one, this in turn is reflected; but as the light that falls on this surface has had to traverse the film of air twice, it is retarded by a certain number of half or whole wave-lengths, and the beautiful phenomena of interference take place, some of the colors of white light being obliterated, while others come to the eye. When the position of the eye changes, the color is seen to change. I have not time to dwell further on this part of my subject, which is discussed in most advanced works on physics, and especially well described in Dr. Eugene Lommel's work on "The Nature of Light." I remarked that if the two surfaces were perfectly plane, there would be one color seen, or else colors of the first or second order would arrange themselves in broad parallel bands, but this would also take place in plates of slight curvature, for the requirement is, as I said, a film of air of equal thickness throughout. You can see at once that this condition could be obtained in a perfect convex surface fitting a perfect concave of the same radius. Fortunately we have a check to guard against this error. To produce a perfect plane, three surfaces must be worked together, unless we have a true plane to commence with; but to make this true plane by this method we must work three together, and if each one comes up to the demands of this most rigorous test, we may rest assured that we have attained a degree of accuracy almost beyond human conception. Let me illustrate. Suppose we have plates 1, 2, and 3, Fig. 11. Suppose 1 and 2 to be accurately convex and 3 accurately concave, of the same radius. Now it is evident that 3 will exactly fit 1 and 2, and that 1 and 2 will separately fit No. 3, but when 1 and 2 are placed together, they will only touch in the center, and there is no possible way to make three plates coincide when they are alternately tested upon one another than to make perfect planes out of them. As it is difficult to see the colors well on metal surfaces, a one-colored light is used, such as the sodium flame, which gives to the eye in our test, dark and bright bands instead of colored ones. When these plates are worked and tested upon one another until they all present the same appearance, one may be reserved for a test plate for future use. Here is a small test plate made by the celebrated Steinheil, and here two made by myself, and I may be pardoned in saying that I was much gratified to find the coincidence so nearly perfect that the limiting error is much less than 0.00001 of an inch. My assistant, with but a few months' experience, has made quite as accurate plates. It is necessary of course to have a glass plate to test the metal plates, as the upper plate must be transparent. So far we have been dealing with perfect surfaces. Let us now see what shall occur in surfaces that are not plane. Suppose we now have our perfect test plate, and it is laid on a plate that has a compound error, say depressed at center and edge and high between these points. If this error is regular, the central bands arrange themselves as in Fig. 9. You may now ask, how are we to know what sort of surface we have? A ready solution is at hand. The bands always travel in the direction of the thickest film of air, hence on lowering the eye, if the convex edge of the bands travel in the direction of the arrow, we are absolutely certain that that part of the surface being tested is convex, while if, as in the central part of the bands, the concave edges advance, we know that part is hollow or too low. Furthermore, any small error will be rigorously detected, with astonishing clearness, and one of the grandest qualities of this test is the absence of "personal equation;" for, given a perfect test plate, it won't lie, neither will it exaggerate. I say, won't lie, but I must guard this by saying that the plates must coincide absolutely in temperature, and the touch of the finger, the heat of the hand, or any disturbance whatever will vitiate the results of this lovely process; but more of that at a future time. If our surface is plane to within a short distance of the edge, and is there overcorrected, or convex, the test shows it, as in Fig. 10. If the whole surface is regularly convex, then concentric rings of a breadth determined by the approach to a perfect plane are seen. If concave, a similar phenomenon is exhibited, except in the case of the convex, the broader rings are near the center, while in the concave they are nearer the edge. In lowering the eye while observing the plates, the rings of the convex plate will advance outward, those of the concave inward. It may be asked by the mechanician, Can this method be used for testing our surface plates? I answer that I have found the scraped surface of iron bright enough to test by sodium light. My assistant in the machine work scraped three 8 inch plates that were tested by this method and found to be very excellent, though it must be evident that a single cut of the scraper would change the spot over which it passed so much as to entirely change the appearance there, but I found I could use the test to get the general outline of the surface under process of correction. These iron plates, I would say, are simply used for preliminary formation of polishers. I may have something to say on the question of surface plates in the future, as I have made some interesting studies on the subject. I must now bring this paper to a close, although I had intended including some interesting studies of curved surfaces. There is, however, matter enough in that subject of itself, especially when we connect it with the idiosyncrasies of the material we have to deal with, a vital part of the subject that I have not touched upon in the present paper. You may now inquire, How critical is this "color test"? To answer this I fear I shall trench upon forbidden grounds, but I call to my help the words of one of our best American physicists, and I quote from a letter in which he says by combined calculation and experiment I have found the limiting error for white light to be 1/50000000 of an inch, and for Na or sodium light about fifty times greater, or less than 1/800000 of an inch. Dr. Alfred Mayer estimated and demonstrated by actual experiment that the smallest black spot on a white ground visible to the naked eye is about 1/800 of an inch at the distance of normal vision, namely, 10 inches, and that a line, which of course has the element of extension, 1/5000 of an inch in thickness could be seen. In our delicate "color test" we may decrease the diameter of our black spot a thousand times and still its perception is possible by the aid of our monochromatic light, and we may diminish our line ten thousand times, yet find it just perceivable on the border land of our test by white light. Do not presume I am so foolish as to even think that the human hand, directed by the human brain, can ever work the material at his command to such a high standard of exactness. No; from the very nature of the material we have to work with, we are forbidden even to hope for such an achievement; and could it be possible that, through some stroke of good fortune, we could attain this high ideal, it would be but for a moment, as from the very nature of our environment it would be but an ignis fatuus. There is, however, to the earnest mind a delight in having a high model of excellence, for as our model is so will our work approximate; and although we may go on approximating our ideal forever, we can never hope to reach that which has been set for us by the great Master Workman.

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[JOURNAL OF GAS LIGHTING.]

PHOTOMETRICAL STANDARDS.

In carrying out a series of photometrical experiments lately, I found that it was a matter of considerable difficulty to keep the flames of the standard candles always at their proper distance from the light to be measured, because the wick was continually changing its position (of course carrying the flame with it), and thus practically lengthening or shortening the scale of the photometer, according as the flame was carried nearer to or farther from the light at the other end of the scale. In order, therefore, to obtain a correct idea of the extent to which this variation of the position of the wick might influence the readings of the photometer scale, I took a continuous number of photographs of the flame of a candle while it was burning in a room quite free from draught; no other person being in it during the experiment except a photographer, who placed sensitive dry plates in a firmly fixed camera, and changed them after an exposure of 30 seconds. In doing this he was careful to keep close to the camera, and disturb the air of the room as little as possible. In front of the candle a plumb-line was suspended, and remained immovable over its center during the whole operation. The candle was allowed to get itself into a normal state of burning, and then the wick was aligned, as shown in the photographs Nos. 1 and 2, after which it was left to itself.



With these photographs (represented in the cuts) I beg to hand you full-sized drawings of the scales of a 100 inch Evans and a 60 inch Letheby photometer, in order to give your readers an opportunity of estimating for themselves the effect which such variations from the true distance between the standard light and that to be measured, as shown in this series of photographs, must exercise on photometrical observations made by the aid of either of the instruments named.

W. SUGG.

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BLEACHING OR DYEING-YARNS AND GOODS IN VACUO.



Many attempts have been made to facilitate the penetration of textile fabrics by the dyeing and bleaching solutions, with which they require to be treated, by carrying out the treatment in vacuo, i.e., in such apparatus as shall allow of the air being withdrawn. The apparatus shown in the annexed engraving—Austrian Pat. Jan. 15, 1884—although not essentially different from those already in use, embodies, the Journal of the Society of Chemical Industry says, some important improvements in detail. It consists of a drum A, the sides of which are constructed of stout netting, carried on a vertical axis working through a stuffing-box, which is fitted in the bottom of the outer or containing vessel or keir B. The air can be exhausted from B by means of an air pump. A contains a central division P, also constructed of netting, into which is inserted the extremity of the tube R, after being twice bent at a right angle. P is also in direct connection with the efflux tube E, E and R serving to convey the dye or bleach solutions to and from the reservoir C. The combination of the rotary motion communicated to A, which contains the goods to be dyed or bleached, with the very thorough penetration and circulation of the liquids effected by means of the vacuum established in B, is found to be eminently favorable to the rapidity and evenness of the dye or bleach.

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ON THE MOULDING OF PORCELAIN.

By CHAS. LAUTH.

The operation of moulding presents numerous advantages over other methods of shaping porcelain, for by this process we avoid irregularities of form, twisting, and visible seams, and can manufacture thin pieces, as well as pieces of large dimensions, of a purity of form that it is impossible to obtain otherwise.

The method of moulding small objects has been described with sufficient detail in technical works, but such is not the case with regard to large ones, and for this reason it will be of interest to quote some practical observations from a note that has been sent me by Mr. Constantine Renard, who, for several years, has had the superintendence of the moulding rooms of the Sevres works.

The process of moulding consists in pouring porcelain paste, thinned with water, into very dry plaster moulds. This mixture gradually hardens against the porous sides with which it is in contact, and, when the thickness of the hardened layer is judged sufficient, the mould is emptied by inverting it. The excess of the liquid paste is thus eliminated, while the thicker parts remain adherent to the plaster. Shortly afterward, the absorption of the water continuing, the paste so shrinks in drying as to allow the object to detach itself from the mould. As may be seen, nothing is simpler when it concerns pieces of small dimensions; but the same is not the case when we have to mould a large one. In this case we cannot get rid of the liquid paste by turning the mould upside down, because of the latter's size, and, on another hand, it is necessary to take special precautions against the subsidence of the paste. Recourse is therefore had to another method. In the first place, an aperture is formed in the lower part of the mould through which the liquid may flow at the desired moment. Afterward, in order to prevent the solidified but still slightly soft paste from settling under its own weight at this moment, it is supported by directing a current of compressed air into the mould, or, through atmospheric pressure, by forming a vacuum in the metallic jacket in which the mould is inclosed.

The history and description of these processes have been several times given, and I shall therefore not dwell upon them, but shall at once proceed to make known the new points that Mr. Renard has communicated to me.

The first point to which it is well to direct the manufacturer's attention is the preparation of the plaster moulds. When it concerns an object of large dimensions, of a vase a yard in height, for example, the moulder is obliged to cut the form or core horizontally into three parts, each of which is moulded separately. To this effect, it is placed upon a core frame and surrounded with a cylinder of sheet zinc. The workman pours the plaster into the space between the latter and the core, and, while doing so, must stir the mass very rapidly with a stick, so that at the moment the plaster sets, it shall be as homogeneous as possible. In spite of such precautions, it is impossible to prevent the densest parts of the plaster from depositing first, through the action of gravity. These will naturally precipitate upon the table or upon the slanting sides of the core, and the mould will therefore present great inequalities as regards porosity. Since this defect exists in each of the pieces that have been prepared in succession, it will be seen that when they come to be superposed for the moulding of the piece, the mould as a whole will be formed of zones of different porosities, which will absorb water from the paste unequally. Farther along we shall see the inconveniences that result from this, and the manner of avoiding them.



The mould, when finished, is dried in a stove. Under such circumstances it often happens that there forms upon the surface of the plaster a hard crust which, although it is of no importance as regards the outside of the mould, is prejudicial to the interior because it considerably diminishes its absorbing power. This trouble may be avoided by coating the surfaces that it is necessary to preserve with clear liquid paste; but Mr. Renard advises that the mould be closed hermetically, so that the interior shall be kept from contact with warm air. In this way it is possible to prevent the plaster from hardening, as a result of too quick a desiccation. I now come to the operation of moulding. In the very first place, it is necessary to examine whether it is well to adopt the arrangement by pressure of air or by vacuum. The form of the objects will determine the choice. A very open piece, like a bowl, must be moulded by vacuum, on account of the difficulty of holding the closing disk in place if it be of very large dimensions. The same is the case with large vases of wood form. On the contrary, an elongated piece tapering from above is more easily moulded by pressure of the air, as are also ovoid vessels 16 to 20 inches in height. In any case it must not be forgotten that the operation by vacuum should be preferred every time the form of the objects is adapted to it, because this process permits of following and directing the drying, while with pressure it is impossible to see anything when once the apparatus is closed.



Moulding by Pressure of the Air.—The plaster mould having been put in place upon the mould board, and the liquid paste having been long and thoroughly stirred in order to make it homogeneous, and get rid of the air bubbles, we open the cock that puts the paste reservoir in communication with the lower part of the mould, care having been taken beforehand to pour a few pints of water into the bottom of the mould. The paste in ascending pushes this water ahead of it, and this slightly wets the plaster and makes the paste rise regularly. When the mould is entirely filled, the paste is still allowed to flow until it slightly exceeds the upper level, and, spreading out over the entire thickness of the plaster, forms a sort of thick flange. The absorption of the liquid begins almost immediately, and, consequently, the level lowers. A new quantity of paste is introduced, and we continue thus, in regulating its flow so as to keep the mould always full. This operation is prolonged until the layer is judged to be sufficiently thick, this depending upon the dimensions, form, or construction of the vessel. The operation may take from one to five hours.

The desired thickness having been obtained, it becomes a question of allowing the paste to descend and at the same time to support the piece by air pressure. The flange spoken of above is quickly cut, and the paste is made to rise again for the last time, in order to form a new flange, but one that this time will be extremely thin; then a perforated disk designed for forming the top joint, and acting as a conduit for the air, is placed upon the mould. This disk is fastened down with a screw press, and when the apparatus is thus arranged the eduction cock is opened, and the air pump maneuvered.

If the flange did not exist, the air would enter between the mould and the piece at the first strokes of the piston, and the piece would be inevitably broken. Its object, then, is to form a hermetical joint, although it must at the same time present but a slight resistance, since, as soon as the liquid paste has flowed out, the piece begins to shrink, and it is necessary that at the first movement downward it shall be able to disengage itself, since it would otherwise crack.

As soon as the piece begins to detach itself from the mould the air enters the apparatus, and the pressure gauge connected with the air pump begins to lower. It is then necessary, without a moment's loss of time, to remove the screw press, the disk, and the upper part of the mould itself, in order to facilitate as much as possible the contraction of the piece. Finally, an hour or an hour and a half later, it is necessary to remove the lower part of the mould, this being done in supporting the entire affair by the middle. The piece and what remains of the mould are, in reality, suspended in the air. All these preparations are designed to prevent cracking.

Moulding by Vacuum.—The operation by vacuum follows the same phases as those just described. It is well, in order to have a very even surface, not to form a vacuum until about three hours after the paste has been made to ascend. Without such a precaution the imperfections in the mould will be shown on the surface of the object by undulations that are irremediable.

The first flange or vein must be preserved, and it is cut off at the moment the piece is detached.

Moulding by vacuum, aside from the advantages noted above, permits of giving the pieces a greater thickness than is obtained in the pressure process. According to Mr. Renard, when it is desired to exceed one inch at the base of the piece (the maximum thickness usually obtained), the operation is as follows: The piece is moulded normally, and it is supported by a vacuum; but, at the moment at which, under ordinary circumstances, it would be detached, the paste is made to ascend a second time, when the first layer (already thick and dry) acts as a sort of supplementary mould, and permits of increasing the thickness by about 2/5 of an inch. The piece is held, as at first, by vacuum, and the paste is introduced again until the desired thickness is obtained.

Whatever be the care taken, accidents are frequent in both processes. They are due, in general, to the irregular contraction of the pieces, caused by a want of homogeneousness in the plaster of the moulds. In fact, as the absorption of the water does not proceed regularly over the entire surface of the piece, zones of dry paste are found in contact with others that are still soft, and hence the formation of folds, and finally the cracking and breaking of the piece. The joints of the moulds are also a cause of frequent loss, on account of the marks that they leave, and that injure the beauty of the form as well as the purity of the profile.

Mr. Renard has devised a remedy for all such inconveniences. He takes unglazed muslin, cuts it into strips, and, before beginning operations, fixes it with a little liquid paste to the interior of the mould. This light fabric in no wise prevents the absorption of the water, and so the operation goes on as usual; but, at the moment of contraction, the piece of porcelain being, so to speak, supported by the muslin, comes put of the mould more easily and with extreme regularity. Under such circumstances all trace of the joint disappears, the imperfections in the mould are unattended with danger, and the largest pieces are moulded with entire safety. In a word, we have here a very important improvement in the process of moulding. The use of muslin is to be recommended, not only in the manufacture of vases, but also in the difficult preparation of large porcelain plates. It is likewise advantageous in the moulding of certain pieces of sculpture that are not very delicate, and, finally, it is very useful when we have to do with a damaged mould, which, instead of being repaired with plaster, can be fixed with well ground wet sand covered with a strip of muslin.

Drying of the Moulded Pieces.—When the moulded pieces become of a proper consistency in the mould, they are exposed to the air and then taken to the drying room. But, as with plaster, the surface of the paste dries very quickly, and this inconvenience (which amounts to nothing in pieces that are to be polished) is very great in pieces that carry ornaments in relief, since the finishing of these is much more difficult, the hardened paste works badly, and frequently flakes off. In order to remedy this inconvenience, it suffices to dust the places to be preserved with powdered dry paste.—Revue Industrielle.

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PHOTO-TRICYCLE APPARATUS.



This consists of a portable folding camera, with screw focusing arrangement, swing back, and an adapter frame placed in the position of the focus screen, allowing the dark slide to be inserted so as to give the horizontal or vertical position to the dry plate when in the camera. To the front and base-board a brass swiveled side bar, made collapsible by means of a center slot, is attached by hinges, and this renders the camera rigid when open or secure when closed. The base-board is supported on a brass plate within which is inserted a ball-and-socket (or universal joint in a new form), permitting the camera to be tilted to any necessary angle, and fixed in such position at will. The whole apparatus is mounted upon a brass telescopic draw-stand, which, by means of clamps, is attached to the steering handle or other convenient part of the tricycle, preferably the form made by Messrs. Rudge & Co., of Coventry, represented in the cut.—Photo. News.

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A PHOTO PRINTING LIGHT.



A printing frame is placed in the carrier, and exposed to the light of a gas burner kept at a fixed distance, behind which is a spherical reflector. The same frame may be used for other purposes.-Photographic News.

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A NEW ACTINOMETER.

A selenium actinometer has been described in the Comptes Rendus in a communication from M. Morize, of Rio de Janeiro. The instrument is used to measure the actinic power of sunlight when the sun is at various altitudes; but the same principle is applicable to other light sources. The sensitive part of the apparatus consists of a cylinder formed of 38 disks of copper, isolated from each other by as many disks of mica. The latter being of smaller diameter than the copper disks, the annular spaces between the two are filled with selenium, by the simple process of rubbing a stick of this substance over the edges, and afterward gently warming. The selenium then presents a grayish appearance, and is ready for use. Connection is made by conductors, on opposite sides, with the odd and even numbers of the disks, which diminishes the resistance of the selenium. The cylinder thus formed is insulated by glass supports in the inside of a vacuum tube, for the purpose of preserving it from the disturbing influence of dark rays. The whole is placed upon a stand, and shielded from reflected light, but fully exposed to that which is to be measured for actinic intensity. If now a constant current of electricity is passed through the apparatus, as indicated by a galvanometer, the variations of the latter will show the effect produced upon the selenium. A scale must be prepared, with the zero point at the greatest possible resistance of the selenium, which corresponds with absolute darkness. The greatest effect of the light would be to annul the resistance of the selenium. Consequently, the cylinder must be withdrawn from the circuit to represent this effect; and the maximum deviation of the galvanometer is then to be observed, and marked 100. By dividing the range of the galvanometer thus obtained into 100 equal parts, the requisite actinometric scale will be established. In practice, the Clamond battery is used to supply the constant current required.

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ASTRONOMICAL PHOTOGRAPHY.

During the last few years, or rather decades of years, it has become rather a trite saying that to advance far in any branch of physical research a fair proficiency in no inconsiderable number of the sister sciences is an absolute necessity. But if this is true in general, none, I think, will question the assertion that a proficient in any of the physical sciences must be fairly conversant with photography as a science, or at least as an art. If we take for example a science which has of late years made rapid strides both in Europe and America, the science of astronomy, we shall not have far to go to find convincing proof that a great portion of the best work that is being done by its votaries is effected by the aid of photography. One eminent astronomer has quite lately gone so far as to declare that we no longer require observers of the heavens, but that their place can be better supplied by the gelatine plate of the photographer; and his words have been echoed by others not less able than himself. "Abolish the observer, and substitute the sensitive plate," is a sensational form of expressing the revolution in observational astronomy that is taking place under our eyes; but, although it suggests a vast amount of truth, it might leave upon the mind an exaggerated impression inimical to the best interests of science.

The award of the highest distinction in astronomy, the gold medal of the Royal Astronomical Society, two years in succession, to those who have been most successful in celestial photography is no doubtful sign of the great value attached to such work. Last year it was Mr. Common who received the highest testimony of the merit due to his splendid photographs of the nebula of Orion; and this year Dr. Huggins, who has drawn much attention to celestial photography, by his successful attempts to picture the solar corona in full daylight, has received a similar acknowledgment of his labors in photographing the spectra of stars and comets and nebulae.

An adequate idea of the progress astronomy is now making by aid of photography can only be formed by a comprehensive view of all that is being at present attempted; but a rapid glance at some of the work may prepare the way for a more thorough investigation. A few years since, the astronomers who had advanced their science by aid of photography were few in number, and their results are soon enumerated. Some good pictures of the solar corona taken during solar eclipses, a series or two of sun-spot photographs, and a very limited number of successful attempts made upon the moon, and planets, and star clusters, were all the fruits of their labors. But now each month we learn of some new and efficient laborer in this field, which gives promise of so rich a harvest.

Each day the sun is photographed at Greenwich, at South Kensington, in India, and at the Physical Observatory of Potsdam, and thus a sure record is obtained of all the spots upon its surface, which may serve for the study of the periodicity of its changes, and for their probable connection with the important phenomena of terrestrial magnetism and meteorology. In France the splendid sun-pictures obtained by Dr. Janssen at the Physical Observatory of Meudon have thrown into the shade all other attempts at a photographic study of the most delicate features of the solar surface.

Dr. Huggins has shown that it is possible to obtain a daily photographic record of the solar prominences, and only lately he has secured results that justified a special expedition to the Alps to photograph the sun's corona, and he has now moved the Admiralty to grant a subsidy to Dr. Gill, the government astronomer at the Cape, by aid of which Mr. Woods can carry on the experiments that were so encouraging last summer in Switzerland.

We may, then, reasonably hope to obtain before long a daily picture of the sun and a photographic record of its prominences, and even of a certain portion of the solar corona; but the precious moments of each solar eclipse will always be invaluable for picturing those wondrous details in the corona that are now shown us by photography, and which can be obtained by photography alone.

Again, how very much is to be learnt in solar physics from the marvelous photographs of the sun's spectrum exhibited last summer by Professor Rowland; photographs that show as many as one hundred and fifty lines between H and K, and which he is still laboring to improve! The extension, too, of the visible solar spectrum into the ultra-violet by Corun, Mascart, and others, adds much to our knowledge of the sun; while the photographs of Abney in the ultrared increase our information in a direction less expected and certainly less easy of attainment. Both these extensions we find most ably utilized in the recent discussion of the very interesting photographs of the spectra of the prominences and of the corona taken during the total eclipse of May 18, 1882; and the photographic results of this eclipse afford ample proof that we can not only obtain pictures of the corona by photography that it would be impossible otherwise to procure, but also that in a few seconds information concerning the nature of the solar atmosphere may be furnished by photography that it would otherwise take centuries to accumulate, even under the most favorable circumstances.

The advantages to be gained by accurate photographs of the moon and planets, that will permit great enlargements, are too obvious to call for lengthened notice in such a rapid sketch as the present; for it is principally in the observation of details that the eye cannot grasp with the required delicacy, or with sufficient rapidity, that photography is so essential for rapid and sure progress.

Like the sketches of a solar eclipse, the drawings that are made of comets, and still more of nebulae, even by the most accomplished artists, are all, to say the least, open to doubt in their delicate details. And the truth of this is so obvious, that it is the expressed opinion of an able astronomer that a single photograph of the nebula of Orion, taken by Mr. Common, would be of more value to posterity than the collective drawings of this interesting object so carefully made by Rosse, Bond, Secchi, and so many others.

Another most important branch of astronomy, that is receiving very great attention at present, is the mapping of the starry heavens; and herein photography will perhaps do its best work for the astronomer. The trial star map by the brothers Henry, of a portion of the Milky Way, which they felt unable to observe satisfactorily by the ordinary methods, is so near absolute perfection that it alone proves the immense superiority of the photographic method in the formation of star maps. Fortunately this subject, which is as vast as it is fundamental, is being taken up vigorously. The Henries are producing a special lens for the work; Mr. Grubb is constructing a special Cassgrain reflector for Mr. Roberts of Maghull; and the Admiralty have instructed Mr. Woods to make this part of his work at the Cape Observatory, under the able direction of Dr. Gill. Besides star maps, clusters, too, and special portions of the heavens are being photographed by the Rev. T.E. Espin, of West Kirby; and such pictures will be of the greatest value, not only in fixing the position at a given date, but also aiding in the determination of magnitude, color, variability, proper motion, and even of the orbits of double and multiple stars, and the possible discovery of new planets and telescopic comets.

Such are some of the many branches of astronomy that are receiving the most valuable aid at present from photography; but the very value of the gift that is bestowed should make exaggeration an impossibility. Photography can well afford to be generous, but it must first be just, in its estimate of the work that has still to be done in astronomy independently of its aid; and although the older science points with just pride to what is being done for her by her younger sister, still she must not forget that now, as in the future, she must depend largely for her progress, not only on the skill of the photographer and the mathematician, but also on the trained eye and ear and hand of her own indefatigable observers.—S.J. Perry, S.J., F.R.S., in Br. Jour. of Photography.

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ELECTRICITY AS A PREVENTIVE OF SCALE IN BOILERS.

The mineral sediment that generally sticks to the sides of steam boilers, and the presence of which is fraught with the utmost danger, resulting in many instances in great injury to life and property, besides eating away the substance of the iron plate, was referred to in a paper lately read by M. Jeannolle before the Paris Academy of Sciences, in which the author described a new method for keeping boilers clean. This method is as follows:

The inside of a steam boiler is placed, by means of piles of a certain power, in reciprocal communication, the current passing at one end through positive, and at the other through negative, wires. In incrusted steam boilers, at a temperature ranging from 212 deg. to 300 deg. Fahr., and a pressure of from 30 to 90 lb. to the square inch, the current thus engendered decomposes the accumulated salts, and precipitates them, from which they may easily be removed, either by means of a special siphon or by means of some other mechanical process. When boilers are free from fur, and where it is intended to keep them free from such, a continuous current may be set up, by means of which the sedimentary salts may be decomposed, and a precipitate produced in a pulverized form, which can be removed with equal facility.

From a series of minute experiments made by M. Jeannolle, it appears that in order to render the various actions of electricity, perfect, it is necessary to coat either with red lead or with pulverized iron, or with any other conductor of electricity, an operation which must be repeated whenever the boiler is emptied with a view to cleaning out. The above system Is being advantageously applied in Calais for removing the incrustations of boilers. The two poles of a battery of ten to twelve Bunsen elements are applied to the ends of the boilers, and after thirty to forty hours the deposits fall from the sides to the bottom. When a boiler has been thus cleared, the formation of new deposits may be prevented by applying a much less energetic current under the same conditions.

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ALPHABET DESIGNED BY GODFREY SYKES.



Among the many designs which have been issued by the South Kensington Museum authorities is the alphabet which we have illustrated here to-day. The letters appear frequently among the decorations of the museum buildings, especially in the refreshment rooms and the Ceramic gallery, where long inscriptions in glazed terra cotta form ornamental friezes. The alphabet has also been engraved to several sizes, and is used for the initial letters in the various official books and art publications relating to the museum, which are published by the Science and Art Department.—Building News.

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OLD WROUGHT IRON GATE.



This gate forms the entrance to Scraptoft Hall, a building of the eighteenth century, now the seat of Captain Barclay, and which stands at about five miles from Leicester, England.—The Architect.

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BRIEF SANITARY MATTERS IN CONNECTION WITH ISOLATED COUNTRY HOUSES.[4]

[Footnote 4: Read before the Boston Society of Civil Engineers, April 1884 Journal A. of E. Societies.]

By E.W. BOWDITCH, C.E.

I am unable to tell you what is generally considered the best practice, for I am not sure there are any definitely established rules; therefore I can only explain my ways of doing such work, which, though I try to make as complete and at the same time as simple as possible, I know to be far from perfect.

Plumbing and drainage work has grown up unconsciously with my landscape gardening, and not finding any texts or practice that seemed wholly satisfactory, I have been forced to devise new arrangements from time to time, according to the requirements of the case in hand.

To give all the details of house plumbing this evening, or any one evening, would be impossible, for lack of time, and not worth while even if there was time, as much of it would prove matter of little or no interest. I will confine my remarks, therefore, to certain elements of the work where my practice differs, I believe, essentially from that of most engineers, and where perhaps my experience, if of no assistance to other members of the Society, may excite their friendly criticism in such a way as to help me.

There are two kinds of country places that I am liable to be called upon to prescribe for:

First. A new place where nothing has been arranged.

Second. An old place where the occupants have been troubled either by their outside arrangements or by fixtures or pipes within.

Under the first head let us suppose a small tract of perhaps two acres of land in some inland town, where the family intends to live but six months in the year, though they are liable to reside there the whole twelve.

There are no sewers and no public water. The soil is a stiff, retentive clay, rather wet in spring. The desire is expressed to have plumbing and drainage that shall be as inexpensive as possible, but that shall be entirely safe.

In considering the arrangements inside the house, I find myself in the same predicament as the French surgeon, a specialist upon setting the bones of the arm, who, when a patient was brought him with his right arm broke, expressed his sorrow at being unable to be of assistance, as his specialty was the left arm.

I have endeavored to post myself thoroughly upon house plumbing, but confess to only knowing partially about the wastes; the supplies I do not feel competent to pass upon.

One class of annoyance caused by plumbing, perhaps the principal one, is due to the soil pipe or some of its fittings.

Second quality of iron, poor hanging, insufficient calking, careless mechanics, putty, cement, rag, or paper joints—all these and a dozen other things are liable to be sources of trouble. Subordinate wastes are apt to be annoying, occasionally, too, to a less extent.

The mechanical work can always be superintended, and within certain limits may be made secure and tight; not so easy, however, with the materials.

There is seldom a valid excuse for ever making waste pipes, within a building, of anything but metal.

Earthen tile is frequently used; also, to a limited extent, brick, stone, and wood; twice I have found canvas—all these, however, are inferior, and should never be accepted or specified. The writer believes that at the present time, hereabouts, lead and iron are more used for wastes than any other materials, and are found the most satisfactory on the whole.

One or two arrangements, relative to the wastes, I have made use of that are not, so far as known, in general use, and that may not be the best, though they have served me many good turns, and I have not succeeded in devising any better.

Soil pipe, as it is usually put in, is apt to be of cast iron, four inches in diameter, and is known in the market as "heavy" or "extra heavy." For some years the tar-coated or black enameled pipe has been the favorite, as being the more reliable, the writer in common with others making use of the same freely, until one day a cracked elbow, tar coated, was detected. Since that time plain, untarred pipe has been specified, and subjected to the so-called kerosene test, which consists of swabbing out each pipe with kerosene or oil and then allowing it to stand for a few hours. A moment's thought will convince any one that when a pipe is asphalted or tar coated it is very difficult to detect either sand holes or small cracks, and the difficulty of proper calking is increased, as lead does not cling so well to the tar as to plain iron.

At present, the kerosene test, so far as the writer is concerned, is a misnomer, because raw linseed oil is used exclusively as giving more satisfactory results, and being less troublesome to apply.

I have here a length of the ordinary "heavy 4" commercial soil pipe, plain, and selected at random. Yesterday noon I had it oiled at my office, in order to be ready for to-night, and you see, by the chalk marks I have made, just where the leaks were and their area. I may say here that a sound pipe of this caliber and standard weight is the exception rather than the rule, and it was selected for this experiment merely to try and show the reaction a little better than the heavier pipe might.

Experiments of this nature I have carried along for the past two years, and I am glad to say that, since I began, the quality of the soil pipe furnished by the dealers for my work seems appreciably better than at first. Whether the poorer pipe is still made and sold to other customers I have no means of knowing; probably it is, however.

A large quantity of the pipe is now being tested at my suggestion by the Superintendent of Construction of the Johns Hopkins Hospital, at Baltimore. I have not yet heard the results from him, but doubtless they will be interesting. A brief summary of the results may be of some interest.

The different makers of soil pipe generally used by plumbers hereabouts are:

Mott & Company, Abendroth, Blakslee, Dighton, Phillips & Weeden, and Bartlett, Hayward & Co.

On 4" extra heavy pipe my results have been as follows:

Percentage passed as good, single hub. 60 per ct. to 70 per ct. Percentage passed as good, double. 20 per ct. to 80 per ct. Percentage passed special castings, including Y's and T's. 60 per ct.

5" pipe extra heavy:

Percentage passed as good, single hub. 25 per ct. to 35 per ct. Percentage passed as good, double. No record. Percentage special castings, including Y's and T's. 60 per ct.

It has been stated to me by dealers that the tar coating does away with the necessity of any such test as the oil; while I am not prepared to acknowledge or deny the statement, it is well known that much poor pipe is tar-coated and sold in the market as good, and when coated it is almost impossible to detect any but very defective work.

The price customers are obliged to pay for soil pipe, either "heavy" or "extra heavy," is very high indeed, even taking off the discounts, and amounts (as I figure it) to $70 per long ton for 4" pipe. The present rate for the best water pipe of the same caliber is about $38 (now $29) per long ton, and the additional charge for soil pipe should guarantee the very best iron in the market, though it appears to be rarely furnished.

It is asserted that all soil pipe is tested to a 50-pound water pressure. I beg leave to question the absolute truth of this, unless it be acknowledged that pipe is sold indiscriminately, whether it bears the test or not, for more than once I have found a single length of soil pipe (5 feet) that could not bear the pressure of a column of water of its own height without leaking.

Having obtained a satisfactory lot of soil pipe and fittings, the next trouble comes with the lead calking. Unfortunately, it is frequently found that very shallow joints are made instead of deep ones, and hard lead used instead of soft. My rule is, soft lead, two runnings and two calkings. By soft lead I mean pig lead, and by hard lead I mean old pipe and scrap lead that may have been melted a dozen times. Incidentally it may be remarked that it is quite difficult to calk a tight joint on the heavy pipe; the process will crack the hub.

The fixtures used in a house are of minor importance—there are dozens of good patterns of every class. If they are carefully put in, and provided with suitable traps placed just as close to the fixture as possible, the result will usually be satisfactory.

Very few instances occur where traps are placed as close to the fixtures they serve as they might be, and yet a very short length of untrapped pipe, when fouled, will sometimes smell dreadfully. A set bowl with trap two feet away may become in time a great nuisance if not properly used. A case in point where the fixture was used both as a bowl and a urinal was in a few months exceedingly offensive—a fact largely (though not wholly) due to its double service.

I have never met two sanitarians who agreed upon the same water-closets, bowls, faucets, traps, etc.

Of course, the soil pipe will be carried, of full size, through the roof, and sufficiently high to clear all windows.

Avoid multiplicity of fixtures or pipes; cut off all fixtures not used at least twice a week, lest their traps dry out; have all plumbing as simple as possible, and try and get it all located so that outside air can be got directly into all closets and bath-rooms. As far as possible, set your fixtures in glass rather than tiles or wood. Carry the lower end of the main drain at least five feet beyond the cellar walls of the building, of cast iron.

Let us now look at the outside work. The main drain (carrying everything except the kitchen and pantry sinks) goes through a ventilated running trap. An indirect fresh air inlet is provided on the house side of the trap (example), to prevent annoyance from puffing or pumping, or, better still, a pipe corresponding to the soil pipe is carried up on the outside of the house.

The running trap ventilator should be of the same diameter as the main drain (4 inch), and serve as a main drain vent also. Carry this pipe on the outside of the house as high as the top of the chimney.

A grease-trap should be provided for the kitchen and pantry sinks. Formerly my custom was to put in brick receptacles; it is now to put in Portland cement traps (Henderson pattern), though perhaps I may succeed in devising a cast-iron one that will answer better. The brick ones were occasionally heaved by the frost, and cracked; the Portland cement ones answer better, and when thoroughly painted with red lead do not soak an appreciable quantity of sewage to be offensive, but are too high priced ($28 each). I have made one or two patterns for cast-iron ones, but none as yet that I feel satisfied with.

Beyond the running trap an Akron pipe should convey the sewage to a tank or cesspool.

Our supposable case is the second most difficult to take care of. The worst would be ledge. We have to contend with, however, hard, wet, impervious clay.

The best way undoubtedly is to underdrain the land, and then to distribute the sewage on the principle of intermittent downward filtration. This is rather expensive, and a customer is rarely willing to pay the bills for the same. I should always advise it as the best; but where not allowed to do so, I have had fair success with shallow French drains connecting with the tank or cesspool.

Siphon tanks, such as are advised by many sanitarians, that were used first in this country, I believe, by Mr. Waring, I have not been very successful with. Obstructions get into the siphon and stop it up, or it gets choked with grease. I prefer a tight tank, provided with a tell-tale, and that is to be opened either by a valve operated by hand, or that is arranged with a standing overflow like a bath tub, and that can be raised and secured by a hook.

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SANITARY COOKING.[5]

[Footnote 5: Read before the Indiana State Sanitary Society, Seymour, March 13, 1884.—The Sanitarian.]

By VIRGINIA L. OPPENHEIMER, M.D., Seymour, Ind.

"We may live without poetry, music, and art, We may live without conscience, and live without heart, We may live without friends, We may live without books, But civilized man cannot live without cooks.

"We may live without books— What is knowledge but grieving? We may live without hope— What is hope but deceiving? We may live without love—what is passion but pining? But where is the man that can live without dining?"

Thus saith the poet, and forthwith turns the world over into the hands of the cook. And into what better hands could you fall? To you, my fat, jolly, four-meals-a-day friend, Mr. Gourmand, but more especially to you, my somber, lean, dyspeptic, two-meals-a-day friend, Mr. Grumbler, the cook is indeed a valuable friend. The cook wields a scepter that is only second in power to that of love; and even love has become soured through the evil instrumentality of the good-looking or bad-cooking cook. This is no jest, it is a very sad fact.

Now, the question arises, how can the cook preserve the health of her patrons, maintain happiness in the family, and yet not throw the gourmands into bankruptcy? Very simple, I assure you.

1. You must have the cook. I mean by this, that not every one can occupy that important office. The greatest consideration in the qualities of a cook is, does she like the work? No one can fulfill the duties of any noteworthy office unless he labors at them with vim and willingness.

2. You must have good articles of food originally.

3. As our honest Iago said, "You must have change."

When one arrives at adult age, he should have learned by experience what articles of food do, and what articles of food do not, agree with him, and to shun the latter, no matter how daintily served or how tempting the circumstances. The man who knows that pates de foie gras, or the livers of abnormally fattened geese, disagree with him, and still eats them, is not to be pitied when all the horrors of dyspepsia overtake him.

The cooking of any article of food has evidently much, very much, to do with its digestibility. It is not the purpose of this paper to teach cooking, but merely to give some general hints as to the best as well as the simplest methods of preparing staple articles of food. The same articles of food can and should be prepared differently on each day of the week. Changes of diet are too likely to be underestimated. By constant change the digestive organs in the average person are prevented from having that repulsion of food which, to a greater or less extent, is likely to result from a sameness of diet continued for a long time.

We often hear from our scientific men that this or that article of food is excellent for muscle, another for brain, another for bone, etc., etc. Now, stubborn facts are like stone walls, against which theories often butt out their beauty and their power. It is well known to almost every one nowadays that well-cooked food, whether it be potatoes, meat and bread, fish, or anything else worthy the name of food, will well maintain, indefinitely, either the philosopher or the hodcarrier.

Many of you know, and all of you ought to know, that the principal ingredients of nearly all our foods are starch and albumen. Starch is the principal nutritive ingredient of vegetables and breadstuffs. Albumen is the principal ingredient of meats, eggs, milk, and other animal derivatives.

Starch never enters the system as starch, but must first be converted into sugar either in the body or out of it. The process of this transformation of starch into sugar is beautifully exemplified in certain plants, such as the beet, the so-called sugar cane, and other growths. The young plant is, to a great extent, composed of starch; as the plant grows older, a substance is produced which is called diastase. Through the influence of this diastase the starch is converted into a peculiar non-crystallizable substance called dextrine, and as the plant matures, this dextrine is transformed into crystallizable sugar.

"Dextrine is a substance that can be produced from starch by the action of dilute acids, alkalies, and malt extract, and by roasting it at a temperature between 284 deg. and 330 deg. F., till it is of a light brown color, and has the odor of overbaked bread."

A simple form of dextrine may be found in the brown crust of bread—that sweetish substance that gives the crust its agreeable flavor. Pure dextrine is an insipid, odorless, yellowish-white, translucent substance, which dissolves in water almost as readily as sugar. As stated above, it is easily converted into dextrose, or glucose, as it is usually named.

This glucose is often sold under the name of sugar, and is the same against which so many of the newspapers waged such a war a year or two ago. These critics were evidently, for the most part, persons who knew little about the subject. Glucose, if free from sulphuric acid or other chemicals, is as harmless as any other form of sugar. Most of our candies contain more or less of it, and are in every way as satisfactory as when manufactured wholly from other sugars.

It is, therefore, self-evident that, as sugar is a necessary article of food, the process which aids the transformation of our starchy foods must necessarily aid digestion. Do not understand me to say by this that, if all our starchy foods were converted into sugar, their digestion would thereby be completed. As I stated a moment ago, this sweet food, if taken into the stomach day after day, would soon cause that particular organ to rebel against this sameness of diet. In order the more clearly to illustrate this point, I will briefly show you how some of the every-day articles of food can be each day differently prepared, and thus be rendered more palatable, and, as a consequence, more digestible; for it is a demonstrated fact that savory foods are far more easily digested than the same foods unsavored.

The art of serving and arranging dishes for the table is an accomplishment in itself. It is very reasonable that all things that go to make up beauty and harmony at the dinner table should add their full quota to the appetite, and, I was about to say, "to the digestion;" but will qualify the statement by saying, to the digestion if the appetite be not porcine.

Our commonest article of food is the potato. Let us see how potatoes—which contain only twenty per cent. of starch, as against eighty-eight per cent. in rice, and sixty-six per cent. in wheat flour—can be prepared as just mentioned. We will look for a moment at the manner in which they are usually served by the average cook:

1, boiled with their jackets on; 2, roasted in the embers; 3, roasted with meat; 4, fried; 5, mashed; 6, salad.

1. Potatoes boiled in their jackets are excellent if properly prepared. But there's the rub. The trouble is, they are too often allowed to boil slowly and too long, and thus become water-soaked, soggy, and solid, and proportionately indigestible. They should be put over a brisk fire, and kept at a brisk boil till done; then drain off the water, sprinkle a little salt over them, and return to the fire a moment to dry thoroughly, when you will find them bursting with their white, mealy contents.

2. Roasted potatoes are general favorites, and very digestible. A more agreeable flavor is imparted to them if roasted in hot embers (wood fire), care being used to keep them covered with the hot embers.

3. Fried potatoes, as they are very generally served, are almost as digestible as rocks, but not so tempting in all their grease-dripping beauty as the latter. Many of you have doubtless seen the potatoes neatly sliced and dumped into a frying pan full of hot lard, where they were permitted to sink or float, and soak and sob for about a half hour or more. When served, they presented the picturesque spectacle of miniature potato islands floating at liberty in a sea of yellow grease. Now, if any of you can relish and digest such a mess as that, I would advise you to leave this clime, and eat tallow candles with the Esquimaux.

If you are fond of fried potatoes, cook them in this way:

Take what boiled potatoes are left from breakfast or dinner; when cold, remove the jackets, and cut into thin slices, season with salt, pepper, and a little Cayenne; have ready a hot frying pan, with enough meat drippings or sweet lard to cover the bottom; put in the potatoes and fry a rich brown, stirring constantly with a knife to prevent burning. Serve very hot.

4. Mashed potatoes will be discussed further on.

5. Potato salads are appetizing and piquant, because they are usually made up with strong condiments, onions, etc. They are, therefore, not very digestible in themselves. Nevertheless, they are so palatable that we cannot easily dispense with them; but, after eating them, if you expect to have inward peace, either split wood, walk eight and a half miles, or take some other light exercise.

More palatable, and proportionately digestible, are the following methods of cooking this useful vegetable:

1, Saratoga potatoes; 2, a la maitre d'hotel; 3, potato croquettes; 4, potatoes and cream; 5, a la Lyonnaise.

1. For Saratogas, pare and slice your potatoes as thin as possible, dropping them into cold water in which is dissolved a tiny piece of alum to make them crisp. Let them remain in the water for an hour or longer. Drain, and wipe perfectly dry with a tea towel. Have ready a quantity of boiling lard. Drop them in, and fry a delicate brown. Drain all grease from them, sprinkle with salt, and serve. Here, in the crisp slices, you will have the much desired dextrine. Or, in other words, your potato is already half digested. Eat three or four potatoes prepared thus, and you feel no inconvenience; but how would you feel did you devour three soggy, water-soaked boiled potatoes?

2. For a la maitre d'hotel, pare the potatoes, cut into pieces half an inch wide, and the length of the potato; drop into cold water until wanted (an hour or so); then drain, and fry in boiling lard. Just as they begin to brown take them out with a skimmer; let them slightly cool; then put back, and fry a rich brown. This makes them puff up, and very attractive.

3. For croquettes, take finely mashed potatoes, and mix with salt, pepper, and butter, and sweet milk or cream enough to moisten thoroughly. Mix with this one well-beaten egg, and form into small balls, taking care to have them smooth. Have ready one plate with a beaten egg upon it, and another with cracker crumbs. Dip each ball into the egg, and then into the crumbs, and brown nicely. Lay the croquettes on brown paper first, to get rid of any superfluous grease, then serve on a napkin.

4. Potatoes and cream are prepared by mincing cold boiled potatoes fine, putting them in a spider with a little melted butter in it, and letting them fry slightly, keeping them well covered. Add a very small piece of fresh butter, season with pepper and salt, and pour over them cream or rich milk. Let them boil up once, and serve. This is a very nice dish, and may be safely taken into delicate stomachs.

5. A la Lyonnaise is prepared as follows: Take five cold potatoes, one onion, butter, salt, and pepper. Slice the onion finely, and fry it in butter until it begins to take color; add the sliced potatoes, salt and pepper to taste, and keep shaking the saucepan until they are somewhat browned. Serve hot.

A few random remarks about the preparation of albuminous foods. If the albumen in food is hardened by prolonged cooking, it is rendered less instead of more digestible. Therefore, the so-called well-cooked meats are really badly-cooked meats. Meats should be only half done, or rare. To do this properly, it is necessary to cook with a quick fire. Steaks should be broiled, not fried. I am in accord with a well-known orator, who said, recently, that "the person who fries a steak should be arrested for cruelty to humanity." Some few meats should always be well cooked before eating.[6]

[Footnote 6: These are the exceptions. Pork, on account of the prevalence of disease in hogs, should be well done.]

The same law holds good with eggs as with meats. A hard-boiled egg is only fit for the stomach of an ostrich; it was never intended by nature to adorn the human stomach. There are very many ways of preparing eggs—by frying, baking, poaching, shirring, etc. I will only describe briefly a few simple methods of making omelets.

In making this elegant dish, never use more than three eggs to an omelet. Plain omelet: Separate the whites and yolks; add a teaspoonful of water to the whites, and beat to a stiff froth; add to the yolks a teaspoonful of water, and beat until light; then season with salt, and about two tablespoonfuls of cream or rich milk. Have your spider very hot; turn your whites and yolks together, and stir lightly to mix them; place a bit of butter in the spider, and immediately pour in your eggs. When set (which takes from ten to twenty seconds, and be careful that it does not brown too much), fold together in a half moon, remove it, sprinkle with powdered sugar, and serve on a hot plate. It should be eaten immediately.

Fruit omelets are made by placing preserved fruits or jellies between the folds. Baked omelets are prepared as above, with the addition of placing in the oven and allowing to brown slightly.

French omelet is prepared in this way: Take a half cup of boiling milk with a half teaspoonful of butter melted in it; pour this over one-half cup of bread crumbs (light bread); add salt, pepper, and the yolks of three eggs beaten very light; mix thoroughly; and lastly, add the whites whipped to a stiff froth. Stir lightly, and fry in butter. When nearly done, fold together in a half moon, and serve immediately.

And thus we might continue ad infinitum, but, as was stated before, it is not my object to instruct you in special cooking, but to illustrate in this manner how much easier it is, to both the cook and your stomachs, to prepare healthful dishes than to do the reverse.

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TIME REQUIRED TO DIGEST DIFFERENT FOODS.

The Monitor de la Salud contains in a recent number the results of some experiments lately made by E. Jessen on the time required for the digestion of certain kinds of food. The stomach of the person on whom the experiments were made was emptied by means of a pump; 100 grammes, equal to 1,544 grains, or about 2-2/3 ounces, of meat, finely chopped and mixed with three times the quantity of water, were introduced. The experiment was considered ended when the matter, on removal by the pump, was found to contain no muscular fibre.

It will be remembered that the gramme weighs nearly 15-1/2 grains, and the cubic centigramme is equal to 1 gramme. The 2-2/3 ounces of meat were therefore mixed with nearly eight ounces of water, before being introduced into the stomach.

The results were as follows:

Beef, raw, and finely chopped. 2 hours. " half cooked. 21/2 " " well cooked. 3 " " slightly roasted. 3 " " well roasted. 4 " Mutton, raw. 2 " Veal. 21/2 " Pork. 3 "

The digestibility of milk was examined in the same way. The quantity used was regulated so that the nitrogen should be the same as in the 100 grammes of beef.

602 cubic centimeters, nearly sixteen ounces, of cow's milk, not boiled, required. 31/2 hours 602 cubic centimeters, boiled. 4 " 602 " " sour. 31/2 " 675 " " skimmed. 31/2 " 656 " " goat's milk, not boiled. 31/2 "

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THE ORGANIZATION AND PLAN OF THE UNITED STATES GEOLOGICAL SURVEY.[7]

[Footnote 7: Communicated to the National Academy of Sciences at the October meeting in 1884.]

By J.W. POWELL.

A Scientific institution or bureau operating under government authority can be controlled by statute and by superior administrative authority but to a limited extent. These operations are practically carried on by specialists, and they can be controlled only in their financial operations and in the general purposes for which investigations are made. Their methods of investigation are their own—originate with themselves, and are carried out by themselves. But in relation to the scientific operations of such a government institution, there is an unofficial authority which, though not immediately felt, ultimately steps in to approve or condemn, viz., the body of scientific men of the country; and though their authority is not exercised antecedently and at every stage of the work, yet it is so potent that no national scientific institution can grow and prosper without their approval, but must sooner or later fall and perish unless sustained by their strong influence.

As director of the Geological Survey, I deeply realize that I owe allegiance to the scientific men of the country, and for this reason I desire to present to the National Academy of Sciences the organization and plan of operations of the Survey.

A TOPOGRAPHIC MAP OF THE UNITED STATUS.

Sound geologic research is based on geography. Without a good topographic map geology cannot even be thoroughly studied, and the publication of the results of geologic investigation is very imperfect without a good map; but with a good map thorough investigation and simple, intelligible publication become possible. Impelled by these considerations, the Survey is making a topographic map of the United States. The geographic basis of this map is a trigonometric survey by which datum points are established throughout the country; that is, base-lines are measured and a triangulation extended therefrom. This trigonometric work is executed on a scale only sufficiently refined for map-making purposes, and will not be directly useful for geodetic purposes in determining the figure of the earth. The hypsometric work is based upon the railroad levels of the country. Throughout the greater part of the country, there is a system of railroad lines, constituting a net-work. The levels or profiles of these roads have been established with reasonable accuracy, and as they cross each other at a multiplicity of points, a system of checks is afforded, so that the railroad surface of the country can be determined therefrom with all the accuracy necessary for the most refined and elaborate topographic maps. From such a hypsometric basis the reliefs for the whole country are determined, by running lines of levels, by trigonometric construction, and in mountainous regions by barometric observation.

The primary triangulation having been made, the topography is executed by a variety of methods, adapted to the peculiar conditions found in various portions of the country. To a large extent the plane-table is used. In the hands of the topographers of the Geological Survey, the plane-table is not simply a portable draughting table for the field; it is practically an instrument of triangulation, and all minor positions of the details of topography are determined through its use by trigonometric construction.

The scale on which the map is made is variable. In some portions of the prairie region, and in the region of the great plains, the topography and the geology alike are simple, and maps on a comparatively small scale are sufficient for practical purposes. For these districts it is proposed to construct the sheets of the map on a scale of 1-250,000, or about four miles to the inch. In the mountain regions of the West the geology is more complex, and the topography more intricate; but to a large extent these regions are uninhabited, and to a more limited extent uninhabitable. It would therefore not be wise to make a topographic or geologic survey of the country on an excessively elaborate plan. Over much of this area the sheets of the map will also be constructed on a scale of 1-250,000, but in special districts that scale will be increased to 1-125,000, and in the case of important mining districts charts will be constructed on a much larger scale. In the eastern portion of the United States two scales are adopted. In the less densely populated country a scale of 1-125,000 is used; in the more densely populated regions a scale of 1-62,500 is adopted, or about one mile to the inch. But throughout the country a few special districts of great importance, because of complex geologic structure, dense population, or other condition, will require charts on still larger scales. The area of the United States, exclusive of Alaska, is about three million square miles, and a map of the United States, constructed on the plan set forth above, will require not less than 2,600 sheets. It may ultimately prove to require more than that, from the fact that the areas to be surveyed on the larger scale have not been fully determined. Besides the number of sheets in the general map of the United States, there will be several hundred special maps on large scales, as above described.

Such is a brief outline of the plan so far as it has been developed at the present time. In this connection it should be stated that the map of the United States can be completed, with the present organization of the Geological Survey, in about 24 years; but it is greatly to be desired that the time for its completion may be materially diminished by increasing the topographic force of the Geological Survey. We ought to have a good topographic map of the United States by the year 1900. About one-fifth of the whole area of the United States, exclusive of Alaska, has been completed on the above plan. This includes all geographic work done in the United States under the auspices of the General Government and under the auspices of State Governments. The map herewith shows those areas that have been surveyed by various organizations on such a scale and in such a manner that the work has been accepted as sufficient for the purposes of the Survey.

Much other work has been done, but not with sufficient refinement and accuracy to be of present value, though such work subserved its purpose in its time. An examination of the map will show that the triangulation of the various organizations is already largely in advance of the topography. The map of the United States will be a great atlas divided into sheets as above indicated. In all of those areas where the survey is on a scale of 1-250,000, a page of the atlas will present an area of one degree in longitude and one degree in latitude. Where the scale is 1-125,000, a page of the atlas-sheet will represent one-fourth of a degree. Where the scale is 1-62,500, the atlas-sheet will represent one-sixteenth of a degree. The degree sheet will be designated by two numbers—one representing latitude, the other longitude. Where the sheets represent fractional degrees, they will be labeled with the same numbers, with the addition of the description of the proper fractional part.

The organization, as at present established, executing this work, is as follows: First, an astronomic and computing division, the officers of which are engaged in determining the geographic coordinates of certain primary points. Second, a triangulation corps engaged in extending a system of triangulation over various portions of the country from measured base-lines. Third, a topographic corps, organized into twenty-seven parties, scattered over various portions of the United States. Such, in brief outline, is the plan for the map of the United States, and the organization by which it is to be made. Mr. Henry Gannett is the Chief Geographer.

PALEONTOLOGY.

Before giving the outline of the plan for the general geologic survey, it will be better to explain the accessory plans and organizations. There are in the Survey, as at present organized, the following paleontologic laboratories:

1. A laboratory of vertebrate paleontology for formations other than the Quaternary. In connection with this laboratory there is a corps of paleontologists. Professor O.C. Marsh is in charge.

2. There is a laboratory of invertebrate paleontology of Quaternary age, with a corps of paleontologists, Mr. Wm. H. Dall being in charge.

3. There is a laboratory of invertebrate paleontology of Cenozoic and Mesozoic age, with a corps of paleontologists. Dr. C.A. White is in charge.

4. There is a laboratory of invertebrate paleontology of Paleozoic age, with a corps of paleontologists. Mr. C.D. Walcott is in charge.

5. There is a laboratory of fossil botany, with a corps of paleobotanists, Mr. Lester F. Ward being in charge.

The paleontologists and paleobotanists connected with the laboratories above described, study and discuss in reports the fossils collected by the general geologists in the field. They also supplement the work of the field geologists by making special collections in important districts and at critical horizons; but the paleontologists are not held responsible for areal and structural geology on the one hand, and the geologists are not held responsible for paleontology on the other hand. In addition to the large number of paleontologists on the regular work of the Geological Survey, as above described, several paleontologists are engaged from time to time to make special studies.

CHEMISTRY.

There is a chemic laboratory attached to the Survey, with a large corps of chemists engaged in a great variety of researches relating to the constitution of waters, minerals, ores, and rocks. A part of the work of this corps is to study the methods of metamorphism and the paragenesis of minerals, and in this connection the chemists do work in the field; but to a large extent they are occupied with the study of the materials collected by the field geologists. Professor F.W. Clarke is in charge of this department.

PHYSICAL RESEARCHES.

There is a physical laboratory in the Survey, with a small corps of men engaged in certain physical researches of prime importance to geologic philosophy. These researches are experimental, and relate to the effect of temperatures, pressures, etc., on rocks. This laboratory is under the charge of the chief chemist.

LITHOLOGY.

There is a lithologic laboratory in the Survey, with a large corps of lithologists engaged in the microscopic study of rocks. These lithologists are field geologists, who examine the collections made by themselves.

STATISTICS.

There is in the Survey a division of mining statistics, with a large corps of men engaged in statistic work, the results of which are published in an annual report entitled "Mineral Resources." Mr. Albert Williams, Jr., is the Chief Statistician of the Survey.

ILLUSTRATIONS.

There is in the Survey a division organized for the purpose of preparing illustrations for paleontologic and geologic reports. Mr. W.H. Holmes is in charge of this division. Illustrations will not hereafter be used for embellishment, but will be strictly confined to the illustration of the text and the presentation of such facts as can be best exhibited by figures and diagrams. All illustrations will, as far as possible, be produced by relief methods, such as wood-engraving, photo-engraving, etc. As large numbers of the reports of the Survey are published, this plan is demanded for economic reasons; but there is another consideration believed to be of still greater importance; illustrations made on stone cannot be used after the first edition, as they deteriorate somewhat by time, and it is customary to use the same lithographic stone for various purposes from time to time. The illustrations made for the reports of the Survey, if on relief-plates that can be cheaply electrotyped, can be used again when needed. This is especially desirable in paleontology, where previously published figures can be introduced for comparative purposes. There are two methods of studying the extinct life of the globe. Fossils are indices of geological formations, and must be grouped by formations to subserve the purpose of geologists. Fossils also have their biologic relations, and should be studied and arranged in biologic groups. Under the plan adopted by the Survey, the illustrations can be used over and over again for such purposes when needed, as reproduction can be made at the small cost of electrotyping. These same illustrations can be used by the public at large in scientific periodicals, text-books, etc. All the illustrations made by the Geological Survey are held for the public to be used in this manner.

LIBRARY.

The library of the Survey now contains more than 25,000 volumes, and is rapidly growing by means of exchanges. It is found necessary to purchase but few books. The librarian, Mr. C.C. Darwin, has a corps of assistants engaged in bibliographic work. It is proposed to prepare a catalogue of American and foreign publications upon American geology, which is to be a general authors' catalogue. In addition to this, it is proposed to publish bibliographies proper of special subjects constituting integral parts of the science of geology.

PUBLICATIONS.

The publications of the Survey are in three series: Annual Reports, Bulletins, and Monographs. The Annual Report constitutes a part of the Report of the Secretary of the Interior for each year, but is a distinct volume. This contains a brief summary of the purposes, plans, and operations of the Survey, prepared by the Director, and short administrative reports from the chiefs of divisions, the whole followed by scientific papers. These papers are selected as being those of most general interest, the object being to make the Annual Report a somewhat popular account of the doings of the Survey, that it may be widely read by the intelligent people of the country. Of this 5,650 copies are published as a part of the Secretary's report, and are distributed by the Secretary of the Interior, Senators, and Members of the House of Representatives; and an extra edition is annually ordered of 15,000 copies, distributed by the Survey and members of the Senate and House of Representatives. Four annual reports have been published; the fifth is now in the hands of the printer.

The Bulletins of the Survey are short papers, and through them somewhat speedy publication is attained. Each bulletin is devoted to some specific topic, in order that the material ultimately published in the bulletins can be classified in any manner desired by scientific men. Nine bulletins have been published, and seven are in press. The bulletins already published vary in size from 5 to 325 pages each; they are sold at the cost of press-work and paper, and vary in price from five to twenty cents each; 4,900 copies of each bulletin are published; 1,900 are distributed by Congress, 3,000 are held for sale and exchange by the Geological Survey.

The Monographs of the Survey are quarto volumes. By this method of publication the more important and elaborate papers are given to the public. Six monographs, with two atlases, have been issued; five monographs, with two atlases, are in press; 1,900 copies of each monograph are distributed by Congress; 3,000 are held for sale and exchange by the Survey at the cost of press-work, paper, and binding. They vary in price from $1.05 to $11.

The chiefs of divisions supervise the publications that originate in their several corps. The general editorial supervision is exercised by the Chief Clerk of the Survey, Mr. James C. Pilling.

GENERAL GEOLOGY.

In organizing the general geologic work, it became necessary, first, to consider what had already been done in various portions of the United States; and for this purpose the compilation of a general geologic map of the United States was begun, together with a Thesaurus of American formations. In addition to this the bibliographic work previously described was initiated, so that the literature relating to American geology should be readily accessible to the workers in the Survey. At this point it became necessary to consider the best methods of apportioning the work; that is, the best methods of dividing the geologic work into parts to be assigned to the different corps of observers. A strictly geographic apportionment was not deemed wise, from the fact that an unscientific division of labor would result, and the same classes of problems would to a large extent be relegated to the several corps operating in field and in the laboratory. It was thought best to divide the work, as far as possible, by subject-matter rather than by territorial areas; yet to some extent the two methods of division will coincide. There are in the Survey at present:

First, a division of glacial geology, and Prof. T.C. Chamberlin, formerly State Geologist of Wisconsin is at its head, with a strong corps of assistants. There is an important field for which definite provision has not yet been made, namely, the study of the loess that constitutes the bluff formations of the Mississippi River and its tributaries. But as this loess proves to be intimately associated with the glacial formations of the same region, it is probable that it will eventually be relegated to the glacial division. Perhaps the division may eventually grow to such an extent that its field of operations will include the whole Quaternary geology.

Second, a division of volcanic geology is organized, and Capt. Clarence E. Dutton, of the Ordnance Corps of the Army, is placed in charge, also with a strong corps of assistants.

Third and fourth, two divisions have been organized to prosecute work on the archaean rocks, embracing within their field not only all rocks of archaean age, but all metamorphic crystalline schists, of whatever age they may be found. The first division has for its chief Prof. Raphael Pumpelly, assisted by a corps of geologists, and the field of his work is the crystalline schists of the Appalachian region, or eastern portion of the United States, extending from northern New England to Georgia. He will also include in his studies certain paleozoic formations which are immediately connected with the crystalline schists and involved in their orographic structure.

The second division for the study of this class of rocks is in charge of Prof. Roland D. Irving, with a corps of geologists, and his field of operation is in the Lake Superior region. It is not proposed at present to undertake the study of the crystalline schists of the Rocky Mountain region.

Fifth, another division has been organized for the study of the areal, structural, and historical geology of the Appalachian region, extending from the Atlantic, westward, to the zone which separates the mountain region from the great valley of the Mississippi. Mr. G.K. Gilbert has charge of this work, and has a large corps of assistants.

Sixth, it seemed desirable, partly for scientific reasons and partly for administrative reasons, that a thorough topographic and geologic survey should be made of the Yellowstone Park, and Mr. Arnold Hague is in charge of the work, with a corps of assistants. When it is completed, his field will be expanded so as to include a large part of the Rocky Mountain region, but the extent of the field is not yet determined.

It will thus be seen that the general geologic work relating to those areas where the terranes are composed of fossiliferous formations is very imperfectly and incompletely organized. The reason for this is twofold: First, the work cannot be performed very successfully until the maps are made; second, the Geological Survey is necessarily diverting much of its force to the construction of maps, and cannot with present appropriations expand the geologic corps so as to extend systematic work in the field over the entire country.

ECONOMIC GEOLOGY.

Under the organic law of the Geological Survey, investigations in economic geology are restricted to those States and Territories in which there are public lands; the extension of the work into the eastern portion of the United States included only that part relating to general geology. Two mining divisions are organized. One, in charge of Mr. George F. Becker, with headquarters at San Francisco, California, is at the present time engaged in the study of the quicksilver districts of California. The other, under charge of Mr. S.F. Emmons, with headquarters at Denver, Colorado, is engaged in studying various mining districts in that State, including silver, gold, iron, and coal areas. Each division has a corps of assistants. The lignite coals of the upper Missouri, also, are under investigation by Mr. Bailey Willis, with a corps of assistants.

EMPLOYES.

The employes on the Geological Survey at the close of September, 1884, were as follows:

Appointed by the President, by and with the advice and consent of the Senate (Director), 1.

Appointed by the Secretary of the Interior, on the recommendation of the Director of the Survey, 134.

Employed by the chiefs of parties in the field, 148.

APPOINTMENTS.

Three classes of appointments are made on the Survey. The statute provides that "the scientific employes of the Geological Survey shall be selected by the Director, subject to the approval of the Secretary of the Interior, exclusively for their qualifications as professional experts." The provisions of this statute apply to all those cases where scientific men are employed who have established a reputation, and in asking for their appointment the Director specifically states his reasons, setting forth the work in which the person is to be employed, together with his qualifications, especially enumerating and characterizing his published works. On such recommendations appointments are invariably made. Young men who have not established a reputation in scientific research are selected through the agency of the Civil Service Commission on special examination, the papers for which are prepared in the Geological Survey. About one-half of the employes, however, are temporary, being engaged for services lasting for a few days or a few months only, largely in the field, and coming under two classes: Skilled laborers and common laborers. Such persons are employed by the Director or by the heads of divisions, and are discharged from the service when no longer needed. It will be seen that the Director is responsible for the selection of the employes, directly for those whom he recommends for appointment, and indirectly for those selected by the Civil Service Commission, as he permanently retains in the work. If, then, improper persons are employed, it is wholly the Director's fault.

The appropriations made for the Geological Survey for the fiscal year ending June 30, 1885, aggregate the sum of $504,040. This sum does not include the amount appropriated for ethnologic researches—$40,000. Nor are the expenses for engraving and printing paid for from the above appropriations, but from appropriations made for the work under the direction of the public printer. It is estimated that the amount needed for engraving and printing for the same fiscal year will exceed $200,000.

THE RELATION OF THE GOVERNMENT SURVEY TO STATE SURVEYS.

The United States Geological Survey is on friendly relations with the various State Surveys. Between the Government Survey and the State Survey of New York, there is direct co-operation. The State Survey of Pennsylvania has rendered valuable assistance to the Government Survey, and negotiations have been entered into for closer relations and more thorough co-operation. The State Surveys of North Carolina, Kentucky, and Alabama are also co-operating with the Government Survey, and the director of the Government Survey is doing all within his power to revive State Surveys. The field for geologic research in the United States is of great magnitude, and the best results can be accomplished only by the labors of many scientific men engaged for a long term of years. For this reason it is believed that surveys should be established in all of the States and Territories. There is work enough for all, and the establishment of local surveys would greatly assist the general work prosecuted under the auspices of the government, and prevent it from falling into perfunctory channels. Its vigor and health will doubtless be promoted by all thorough local research.