3. Detailed Study of the Spectra of the Brighter Stars.—This work has been carried on with the 11 inch photographic telescope used by Dr. Draper in his later researches. A wooden observatory was constructed about 20 feet square. This was surmounted by a dome having a clear diameter of 18 feet on the inside. The dome had a wooden frame, sheathed and covered with canvas. It rested on eight cast iron wheels, and was easily moved by hand, the power being directly applied. Work was begun upon it in June, and the first observations were made with the telescope in October.

Two prisms were formed by splitting a thick plate of glass diagonally. These gave such good results that two others were made in the same way, and the entire battery of four prisms is ordinarily used. The safety and convenience of handling the prisms is greatly increased by placing them in square brass boxes, each of which slides into place like a drawer. Any combination of the prisms may thus be employed. As is usual in such an investigation, a great variety of difficulties have been encountered, and the most important of them have now been overcome.

4. Faint Stellar Spectra.—The 28 inch reflector will be used for the study of the spectra of the faint stars, and also for the fainter portions near the ends of the spectra of the brighter stars. The form of spectroscope mentioned above, in which the collimator and slit are replaced by a concave lens, will be tried. The objects to be examined are, first, the stars known to be variable, with the expectation that some evidence may be afforded of the cause of the variation. The stars whose spectrum is known to be banded, to contain bright lines, or to be peculiar in other respects, will also be examined systematically. Experiments will also be tried with orthochromatic plates and the use of a colored absorbing medium, in order to photograph the red portions of the spectra of the bright stars. Quartz will also be tried to extend the images toward the ultra-violet.

5. Absorption Spectra.—The ordinary form of comparison spectrum cannot be employed on account of the absence of a slit. The most promising method of determining the wave lengths of the stellar spectra is to interpose some absorbent medium. Experiments are in progress with hyponitric fumes and other substances. A tank containing one of these materials is interposed and the spectra photographed through it. The stellar spectra will then be traversed by lines resulting from the absorption of the media thus interposed, and, after their wave lengths are once determined, they serve as a precise standard to which the stellar lines may be referred. The absorption lines of the terrestrial atmosphere would form the best standard for this purpose if those which are sufficiently fine can be photographed.

6. Wave Lengths.—The determination of the wave lengths of the lines in the stellar spectra will form an important part of the work which has not yet been begun. The approximate wave lengths can readily be found from a comparison with the solar spectrum, a sufficient number of solar lines being present in most stellar spectra. If, then, satisfactory results are obtained in the preceding investigation, the motion of the stars can probably be determined with a high degree of precision. The identification of the lines with those of terrestrial substances will of course form a part of the work, but the details will be considered subsequently.

From the above statement it will be seen that photographic apparatus has been furnished on a scale unequaled elsewhere. But what is more important, Mrs. Draper has not only provided the means for keeping these instruments actively employed, several of them during the whole of every clear night, but also of reducing the results by a considerable force of computers, and of publishing them in a suitable form. A field of work of great extent and promise is open, and there seems to be an opportunity to erect to the name of Dr. Henry Draper a memorial such as heretofore no astronomer has received. One cannot but hope that such an example may be imitated in other departments of astronomy, and that hereafter other names may be commemorated, not by a needless duplication of unsupported observatories, but by the more lasting monuments of useful work accomplished.

EDWARD C. PICKERING,

Director of Harvard College Observatory.

Cambridge, Mass., U.S.A., March 1, 1887.

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THE WINNER OF THE DERBY.

The dark bay colt Merry Hampton had never run in public before winning the Derby on the 25th of May last. This colt, by Hampton out of Doll Tear-sheet, was one of Mr. Crowther Harrison's draught of yearlings sent up to the Doncaster sales in 1885, and fell to the bid of Mr. T. Spence, acting for Mr. Abingdon, for 3,100 guineas. The Oaks, on May 27, was won by a daughter of the same sire. Merry Hampton is to compete for the Grand Prize of Paris and for the St. Leger. He has also liabilities in the Thirty-ninth Triennial and Grand Duke Michael stakes at Newmarket, First October; Newmarket Derby at the Second October; Ascot Derby and Twenty-fifth New Biennial; Drawing-room stakes at Goodwood; Great International Breeders' Foal stakes at Kempton Park, August; North Derby at Newcastle, Summer; St. George stakes at Liverpool, July; Bickerstaffe stakes and St. Leger at Liverpool, August; Midland Derby stakes at Leicester, July; and Ebor St. Leger at York, August; in addition to the following races in 1888: Champion stakes at Newmarket, Second October; Rous Memorial and Hardwicke stakes at Ascot, and Eclipse stakes at Sandown Park, Second Summer. Merry Hampton's name also appears in the Kempton Park Royal stakes of 10,000 sovereigns at the Spring Meeting of 1889.—Ill. London News.



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THE FALLS OF GAIRSOPPA.

At the extreme south of the presidency of Bombay, separating the district of Kanara from the territory of Mysore, are the too little known Falls of Gairsoppa.

Far higher than Niagara, four distinct divisions of the river Shiravatti (traditionally created by a cleft made by the arrow of the great god Rama) fall over a precipice of gneiss rock into an abyss eight hundred feet below. Each of these cataracts differs in type of flow.

The "Rajah," eight hundred and thirty feet, and at a breadth of fifty-six, shoots silent and sheer over an uplifted lip of rock in the bed of the stream, casting a dark shadow behind him when faced by the sun; the "Roarer" makes noise enough in its headlong rush to vibrate the strong, stone-built travelers' bungalow on the heights above; the "Rocket" is straight in descent, and, as a commentator has already remarked, as much like a rocket as anything else; and "La Dame Blanche," a triptych of rhythmical flow, spreads a dainty, silky, sheen of white, whispering, glistening, softly falling water over a slightly shelving width of rock, touched here and there with prismatic color and strong light.



At the bottom of the chasm, seven hundred feet across, and stretching over a muddy, turbulent, seething cauldron of spray, a brilliantly distinct rainbow in the full light of day may be seen with its scarcely less glorious reflection, dazzlingly beautiful.

In these regions 210 inches of rain is an average downpour for the monsoon between May and October, the heaviest fall being generally in July. The cataracts then become frequently confluent, though not more picturesque. They are then too difficult of access, and the whole district is very malarious. December and January are the best months for travelers, before the dry season fairly sets in again, during which there is but little water, even insufficient to form four distinct falls.

The best route to them is from Bombay to Honaurre by sea, via Kawai, and on to Old Gairsoppa by river boat and palanquin to the "Jog," as the special points of interest (the "Falls") are called by the Kanarese.

To the enthusiastic shikari, however, the way from Hubli (on the Southern Mahratta Railway, easily reached by G.I.P. line from Bombay), taking him, as it does, through the very happiest hunting grounds of the presidency, where all game, small and large, abounds, will have attraction enough; and at Giddapur, the last stage, within twelve miles of the Falls, there is a courteous English-speaking native magistrate, willing and able to help the traveler on his way. Our engravings are from drawings by Mr. J.E. Page, C.E.—London Graphic.

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SPONGES.

As the last of a course of lectures upon "Recent Scientific Researches in Australasia," Dr. R. Von Ledenfeld lately delivered a lecture at the Royal Institution, upon "Recent Additions to our Knowledge of Sponges." The lecturer did not confine himself to the sponges of Australia alone, but gave a resume of the results of recent investigations on sponges, together with several new interesting details observed more especially in studying the growth of Australian sponges. With a passing reference to some peculiarities of the lower marine animals of the Australian coast, Dr. Ledenfeld remarked upon the preponderance of sponges over other forms of marine life in that part of the world. It has long been a point of discussion as to whether sponges belong to the vegetable or animal kingdom, but naturalists are now generally agreed in regarding them as animals, a conclusion, the lecturer remarked, that Aristotle had also arrived at.

Sponges grow in a variety of more or less irregular shapes, but it has been observed that the most regular structures occur in the calcareous species. As to color, Dr. Ledenfeld remarked that some of the Australian sponges are of exceptionally brilliant hues, while others range from the black of the common sponge (Euspongia officinalis) to a pure white. Also, it may be remarked, the sponges growing in deep water are of less decided color and more elastic in character than those living in shallow water, and from the last named quality are more valuable in commerce. The irregular honeycombed appearance of the sponge is due to a most complicated canal system, consisting of a series of chambers through which the water is drawn by the animal in always the same direction.

The inhalent pores are very minute, and open into small subdermal cavities which communicate by means of interradial tubes with the ciliated chambers, the latter being very small ramifications of the interradial channels, and in them the movement causing the current of water is maintained. From hence all faecal and other matter is discharged through the oscula, the larger openings observed on the surface of the sponge. Dr. Ledenfeld showed the different parts of sponges by means of microscopic slides thrown on to a screen, and also the shape and arrangement of the chambers in different species. The ciliated chambers especially attracted attention. They are very small and circular, and the interior is clothed with cells very similar to the cilia cells in higher animal life.

These cells are arranged around the ciliated chambers in the form of a collar, and from each cell flagella protrude, which are in continual motion. These flagella, like bats' wings, are capable of being bent in only one direction, so that, in the course of their pendulum-like motion, in the movement one way the flagella are bent, while in the return movement they remain stiff, thus causing a current of water always flowing in one and the same direction. These ciliated chambers are easily detected in the sponge by means of a microscope, as they appear more highly colored. After the lecturer had thus given a general outline of the structure of the sponge, he drew attention to the character of its food and its method of digestion. It is not known exactly what the sponge lives upon, but if upon other animals they must be necessarily very small, owing to the size of its inhalent pores.

The sponge, like the tape-worm, has no stomach, but must absorb its food through the outer skin from matter in a soluble state, similarly to the roots of trees. This process of absorption is probably accomplished in the interradial or ciliated chambers, more probably in the former, as the latter are generally considered excretory in function. Lime or silica must also be absorbed from the water by most sponges in order to make up the skeleton. The skeleton of calcareous sponges consists of a number of spicules composed of carbonate of lime. These spicules are of very varied though regular shape, but ordinarily assume a rod-like needle shape or else a stellate form. In silicious sponges the spicules are composed of silica, and are generally deposited around axial rods in concentric layers. The spicules are joined together and cemented by a body that has been named "spongin," which has much the same chemical composition as silk, and, like silk, is very elastic. In some varieties of sponges, especially in the kinds which come into the market, the skeleton is almost entirely composed of fibers of pure "spongin." These fibers are so close together as to draw up water by capillary action, and, indeed, a great deal in the value of a sponge depends upon the fineness and tenuity of these fibers.

Dr. Ledenfeld again illustrated this stage of his lecture by means of a number of microscopic slides in which the variety of shape and size of these spicules and "spongin" fibers were shown. The spicules are some crutch-like, others spined or echinated, while the deep-sea sponges appear to grow long thick spicules, which attach the sponge to the ground by means of grapnel-like ends. In some cases the skeleton seems to be more or less replaced by sand, the small grains of which are cemented together by the "spongin."

Dr. Ledenfeld then drew attention to the presence of more highly developed organs in the sponge. Muscles pervade the whole tissue of the sponge, but are found more particularly in the superficial parts. One set of muscles affect the size of the inhalent pores, causing them to contract or expand, while another set are able to close the pores altogether, thus acting as a protection from the attack of an enemy. All these muscles are composed of spindle shaped cells, which are capable of spasmodic motion, but recently in an Australian sponge, the Euspongia canalicula, the lecturer said he had observed muscles approaching very nearly in character those of the human frame.

That sponges have nerves is a discovery of recent date by a member of the Royal Microscopical Society. Dr. Ledenfeld also about the same time found indications of the presence of a nervous system, but the form in which he observed the nerves at first apparently differed from those observed simultaneously. This difference, however, he afterward found to be due to the manner in which the section had been prepared for observation. The nerves consist of two cells at the base of a cone-like projection on the epidermis, and from each cell a fiber runs to the point of the cone, besides several others connecting them with the interior of the sponge.

It is remarkable that here again Aristotle has predicted that sponges have a nervous system, basing his statement on the fact that ancient Greek mariners foretold storms by the alleged contraction of the sponge. The reproductive organs of sponges are also very highly developed, and both ova and spermatozoa are found throughout the sponge, though more concentrated in the interior. The ova consist of spherical cells, while the spermatozoa resemble an arrow-head in shape. It has not yet been ascertained whether two sexes exist in sponges, or whether the ova and spermatozoa are produced at different periods by the same sponge. When the embryo has become partly developed, it detaches itself from the parent sponge, and, issuing from the oscula, propels itself through the water by means of a number of flagella.

Silicious spicules next appear in its structure, and it then attaches itself to a rock and assumes its mature form. Sponges are most numerous in the waters of the temperate and sub-tropical zones, and the salt-water varieties are by far more numerous than the fresh water. Thus, while there are not more than ten fresh-water species known, Dr. Ledenfeld remarked that about one thousand species of salt-water sponges had been recognized. Each species of the salt-water sponge is, however, generally found only in limited areas, and very few, all of which inhabit deep water, are cosmopolitan. This is the more remarkable as Dr. Ledenfeld asserts that all the sponges inhabiting the rivers of Australia are identical with the fresh-water sponges of Europe, and in order to explain this fact he put forward a rather interesting theory. He assumes that sponge life in rivers has been originally generated by the introduction of a single, or at most two or three germs by means of aquatic birds. The inbreeding consequent upon this paucity of sponge life has produced a certain fixity of character in fresh-water sponges, and is in direct opposition to the effects of hybridization in the salt-water sponges, by which they have acquired the capacity of adapting themselves to local circumstances.

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HERBET'S TEPID DOUCHE.

Keeping the body clean is indispensable for the preservation of good health, through obtaining an operation of the skin and expelling matter whose presence aids in the development of diseases. It is unfortunately necessary to say that, considering the population as a whole, the proportion of those who take baths is very small. This is due to the fact that the habit of cleanliness, which should become a necessity, has not been early inculcated in every individual; and the reason that this complement to education is not realized is because the means of satisfying its exigencies are usually wanting.

We shall not speak of the improved processes that are used solely by the rich or well-to-do, as these become impracticable where it is a question of the working classes or of large masses of individuals. It is, in fact, the last named category that interests us, and we are convinced that if we get young soldiers and children to hold dirtiness in horror, we shall be sure that they will later on take care of their bodies themselves.

The most tempting solution of this question of washing seems to be found in the use of large pools of running tepid water; but such a process is too costly for general use, and the most economical one, without doubt, consists in giving tepid douches.



To our knowledge, the only apparatus in this line that has been devised was exhibited last year at the exhibition of hygiene in the Loban barracks. It has been used daily for six years in several garrisons, and therefore has the sanction of practice.

This apparatus, which is due to Mr. Herbet, consists of a steam boiler and of an ejector fixed to a reservoir of water and provided with a rubber tube to which a nozzle is attached. The steam generated in the boiler passes into the ejector, sucks up the water and forces it out in a tepid state.

The apparatus thus established did not sufficiently fulfill the purpose for which it was designed. It was necessary to have a means of varying the temperature of the water projected, according to the season and temperature of the air, to have an instantaneous and simple method of regulating the apparatus, that could be understood by any operator, and to have the apparatus under the control of the person holding the nozzle. These difficulties have been solved very simply by causing the orifice of the nozzle to vary. This nozzle, from whence the jet escapes, is formed of rings that screw together. When the nozzle is entire, the jet escapes at a temperature of say 40 deg.. When the first ring is unscrewed, the water will make its exit at a temperature of 38 deg.. In order to lower the temperature still further, it is only necessary to unscrew the other rings in succession, until the desired temperature has been obtained.

As it is, the apparatus is rendering great services where it has been introduced; for example, at Besancon and Belfort. It serves, in fact, for an entire garrison, while that before, the washing was done in each regiment, thus requiring the use of much space and causing much loss of time.

Eight men are washed at once for five minutes, say 96 men per hour. Every minute the men turn right about face, and when they are in file each rubs the other's back.

Twenty-two pounds of coal and 260 gallons of water are consumed per hour, and the boiler produces 130 lb. of steam.—Le Genie Civil.

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HOW TO MAKE A STAR FINDER.

Being all of wood, it is easily made by any one who can use a few tools, the only bit of lathe work necessary being the turned shoulder, K, of polar axis. A is the baseboard, 9 in. by 5 in., near each corner of which is inserted an ordinary wood screw, S S, for the purpose of leveling the base, to which two side pieces are nailed, having the angle, x, equal to the co-latitude of the place. On to these side pieces is fastened another board, on which is marked the hour circle, F. Through this board passes the lower end of the polar axis, having a shoulder turned up on it at K, and is secured by a wooden collar and pin underneath. On to the upper part of the polar axis is fastened the declination circle, C, 51/2 in. diameter, made of 1/4 in. baywood, having the outer rim of a thin compass card divided into degrees pasted on to it. The hour circle, F, is half of a similar card, with the hours painted underneath, and divided to 20 minutes. G is the hour index. D is a straight wooden pointer, 12 in. long, having a piece of brass tube, E, attached, and a small opening at J, into which is fixed the point of a common pin by which to set the pointer in declination. H is a nut to clamp pointer in position. By this simple toy affair I have often picked up the planet Venus at midday when visible to the naked eye.—T.R. Clapham in English Mechanic.



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The best mode of finding or tracing trichinae in pork by means of a microscope is the following: Cut a very thin longitudinal slice of the muscle by means of a very sharp knife or razor. Press it between two glass slips, and examine by transmitted light, The coiled trichinae may be readily distinguished from the muscle fiber.

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