A new species (Cribraria dictydioides) from our thus giving great facility for the eye-piece to slip park is reported on exhibition. Good slides of out, and also for observing the stars, advantages Microsporon furfur, probably the cause of Tinea not useful in this country. His binocular prisms slip versicolor of the skin, and of Achorion schonleinlii, entirely out, instead of being checked in proper an alleged cause of Tinea favosa, or ring vorm, position by a stop. The fine adjustment is still reboth difficult to obtain and preserve, are re-tained on the end of the body. ported.

We note a marked advance in the preservation of delicate fungi, and of fresh water algae. Many of these slides retained the natural form and color almost unchanged, and all such were preserved in camphor water one ounce and glycerine about six drops. Wickersheimer's fluid is totally unfit for such work.

Many beautiful polarizing objects were well shown; the Camdem Society contributed nice work in this line. Esculine and naphthaline were among the most beautiful, but it is an error to exhibit these thin crystals under the binocular with the second eye-pieces, because such displays give bad definition.

The

Beck has removed the flat foot, of whatever shape, from all of his instruments, and they all stand on three toes, and are therefore steady. His new "International" stand, which was exhibited, presents some improvements of interest. stage is 63 inches in diameter, and has of an inch lateral motion, and nearly that in vertical direction. Motion is given by a screw and rack opposed by A few marine algæ mounted in balsam ob- springs, which are claimed to obviate loss of motained our sympathetic commiseration that these tion-a great improvement over his former stages. beautiful" weeds of the sea" should be so viciously The stage rotates around the optical axis; and also treated. No intelligible traces were left of the around its own axis by means of a milled-head pinliving things. May our eyes never be asked to wit-ion, enabling it to be completely inverted, and a gradness such relics again. Put all marine algae in uated circle registers the degrees as it goes round. Goadby's solution, and many will be preserved un- All the illuminating apparatus, if desired, swings changed. around a centre level with the stage. The obliquity of illumination is registered on a large graduated circle, which is movable up and down, carrying with it all illuminating apparatus. To fix the body in any position a lever handled-clamp is attached to one trunnion. The fine adjustment is retained on the end of the body. If the microscope can be claimed as an instrument of supreme precision, it Among miscellaneous objects we report slides of is wrong to place the fine adjustment on the body. young oysters in motion; sections of nummulitic Every time it is moved the magnifying power of the limestone, from which the pyramids were built; instrument is changed, and an error is introduced, diatoms covered with iron sulphuret; butterfly and the microscope is just that much not an inscales arranged in beautiful bouquets; micrographs, strument of precision. Means have been found to and the electric spark as developed between two remedy that defect, and all possible sources of error pencil points. In turning from this part of our should be eliminated from the microscopes of the report we suggest the possibility of improvement in future, just as soon as means are found to do it. the manner of showing some objects. Expertness Another large instrument made by Beck, having in microscopic display is best learned-and per- a stage motion of four inches in either direction, is haps learned only-by much practice in the resolu- reported. The binocular body is carried at the end tion of difficult test objects, because in such work of a long horizontal bar. As in some other microgreatest attention to illumination and adjustment scopes, the body may be detached when the instruof lenses is essential, and when that experience is ment can be used for dissection. The plan of carryonce thus acquired it influences, for best results, ing the body on a horizontal bar is a retrograde all other disp ays. step in the construction of microscopes. Only for special purposes such plan has been abandoned by most makers, because steadiness cannot be secured except by great massiveness or by some compensating contrivance.

We observed many binocular microscopes badly illuminated without achromatic condensers or an equivalent. This is an error. It is not possible to to get best results with the binocular without a condenser below the stage. In all microscopic work command superabundant light; it is easy to moderate it to suit special wants.

In microscopes some improvements and novelties may be reported for the past year. A small folding microscope, standing very firmly when in use, costing fifteen dollars-exhibited by Queen & Co.-is worthy of report.

All of Crouch's instruments on exhibition, except his largest stand, turn down beyond the horizontal,

Zentmayer's improved "Centennial" stand was shown at our meeting. Its new mechanical stage, five inches in diameter, is claimed as the thinnest yet made. Light 70° oblique is admitted beneath it. Milled heads move it vertically 1 inches, and laterally 14 inches. It may be inverted, if desired, retaining still the object in the centre of rotation of the sub-stage. This point is realised by an ingenious eccentric fitting which carries the stage and does not interfere with greatest stability. The

changed from the first Saturday to the last Thursday in every month.

centering of the sub-stage is effected by means compact and ridiculously simple. The plan of swinging the sub-stage is well known and not capa- Dr. Ford then read his paper upon "The Relation ble of improvement. It is the most simple plan of the Microscope to the Atomic Theory of Matter," yet devised for that purpose. The fine adjustment in which he speculated upon the query "can we moves the entire body without changing its length. hope that the microscope will show us an atom, or The finish and workmanship, and the motions of a molecule ?" He defined an atom and molecule, this instrument place it in precision, simplicity, and spoke of the highest magnifying power that and excellence far ahead of all other microscopes had been attained in the best objective that had at our meeting. Since this microscope appeared yet been produced. He referred to Huxley's stateat our Centennial Exhibition for the first time, ment of three years ago, in which he said that if many skillful makers have aimed to receive some of objective makers could not produce lenses that its advantages by ingenious mechanical devices, would show the spaces between lines 100,000 of an but none yet have approached its classical simpli- inch apart, a molecule would never be seen. But city and fewness of parts. This instrument marked in 1880, Helmholtz has seen Nobert's lines ruled a new departure in the construction of microscopes, 112,000 to the inch, and yet the molecule remains and without injustice your committee can say no unseen. He spoke of Prof. Rogers' theory, that less. the probable limit of the eye's capability of seeing We report two lamps attached to microscopes in is about one 4,000,000th of an inch. He commented place of the mirrors. One was an ordinary Beck's upon the wonderful rulings upon glass made by lamp fitted with a carrier for the purpose. It has Nobert and Mr. Fasoldt, the latter having ruled facilities for centering in all directions. The other, lines, by means of a delicate machine, that nummade by Zentmayer, was three inches high-in-bered ten millions to the inch. The maker, of cluding chimney of blue glass—and about 14 inches course, had never seen the lines he had ruled, but wide. It could be adjusted without rack in every direction, gives out no perceptible heat of a hot night, and will burn without refilling for six hours. With Wenham's modified binocular prism it gives superabundant light in both fields, with a twentieth objective. With an ordinary prism it fills equally well both fields with all lenses up to a fifth. It requires only a slight addition to the ordinary condenser to make it very desirable. It is elegantly

made.

We desire to express gratification and appreciation for the company of our friends from West Chester, Camden, and from Harrisburg, and to acknowledge the additional interest which they gave to the meeting.

In concluding our report your committee would suggest that inasmuch as these annual meetings are strictly social and scientific, and are given at great responsibility and expense, in order for our own better education and to awaken among our in telligent citizens a love for the beautiful things which the microscope can reveal, such meetings be kept entirely clear from all attemps to placard into notoriety either private members or officers of the society.

R. S. KENDERDINE,
J. G. HUNT,
T. W. STARR.

Elmira Microscopical Society. The regular meeting of this Society was held Dec. 2nd, President S. O. Gleason, M.D., in the chair.

he knew they were there, because his machine had made them, and were only waiting for some objective to reveal them. His band of 90,000 to the inch had been seen by many microscopists. The strim upon the Amphipleura Pellucida, numbering 132,000 to the inch, are now plainly resolved by the best objectives of wide angular aperture. This is the best that has so far been accomplished, leaving the resolution of the molecule a thing to be accomplished in the distant future.

He next dwelt upon an easy method of determining the amplifying power of an objective, by means of the camera lucida and the micrometer slide. Gave examples of the relative magnifying power of the highest objective.

Liebig says of the atomic theory that, "the chemist merely maintains the firm fonndations of his science when he declares the existence of physical atoms and molecules as an incontrovertible truth," although, like the ruler of Fasoldt's lines, he has never seen them, but just knows they are there. Prof. Helmholtz has determined, approximately, the diameter of a single molecule of water, which he estimates at one 250,000,000th of an inch. The Professor then described Helmholtz's method of measurement by means of a soap-bubble and the wave-lengths of light.

He next commented upon the construction of our present lenses and of the microscope of the future, with possible diamond and sapphire lenses, possessFrank Collingwood, C.E., of New York, was ing greater refractive power, but leaving his attenelected an honorary member. Letters read from tive audience to infer that an atom and molecule S. H. Gage, of Cornell University, and from J. W. would probably never be revealed, notwithstanding Sidle, of Lancaster, Pa. Dr. Krackowizer appointed the great improvements likely to be developed in essayist for the next meeting. Time of meeting microscopic cbjectives.

At a late hour the society adjourned, with thanks to Prof. Ford for his instructive and interesting lecture.

The next meeting occurs on the last Thursday in December, at the same hour and place.

THAD S. UP DE GRAFF, Sec'y.

Current Notes.

A Simple and Convenient Zoophyte Trough.-Every one knows the difficulty of cleaning the common zoophyte trough after water has been kept standing in it for some time. and to most of those who have used the trough to Wellesley College Microscopical Society. any considerable extent the difficulty of repairThe second regular meeting of the Wellesley Col-ing it when broken is familiar knowledge. To lege Microscopical Society was held Monday even- avoid these difficulties, Mr. Walmsley, whose skill ing, Dec. 13th, the President, Miss Hayes, in the as a preparer is well known, has devised the little chair. The following papers were presented:

piece of apparatus shown in the annexed engrav

A paper on the Yeast Plant, by Miss D. F. Water-ing. We have here a zoophyte trough which can man; also a paper by Miss E. Hurll, on the Detection of Forgery by the aid of the Microscope.

Professor Nunn gave an account of a discovery she had lately made of the generation of amoebae, in a remarkable manner, from an infusion of the yolk of hen's egg, in Pasteur 8 Fluid. In about ten days, and when the odor of decomposition had begun to be quite strong, amoeba were found in such abundance as to form a creamy deposit on the surface of the liquid; and a drop examined from any part of the fluid showed hundreds on the field. They varied greatly in size and had a remarkably active amoeboid movement. Generally a nucleus in vacuo could be distinctly seen. They seem not to make their appearance in water and egg alone, and apparently flourish best when ammonium tartrate is replaced by pepsin. The whole history, whether they originate from white or yellow yolk, and in what manner, has not been ascertained, but it would seem that the matter involves questions of considerable interest.

There were shown under the microscope 1st. Specimens of the Yeast Plant.

2nd. True and forged signatures, showing the particulars in which they differ, not discernible to the naked eye, but easily seen when subjected to the microscope. L. F. CLARKE, Cor. Secretary.

Microscopical Society of Central Illinois. The third regular meeting of this Society was adjourned from the 11th of November, to the 18th, to enable some of its members, who were attending the Tri-State Medical Association, in Louisville, Ky., to be present. The paper for the evening was prepared and read by Dr. Matthews, the President. The subject, "The Science of Optics as Applied to the Microscope," was well handled.

The doctor has made this subject his especial study. His elucidations were clear and thorough. His blackboard illustrations were very fine.

A number of interesting objects prepared by the members were then examined.

be taken entirely to pieces in a few seconds, so that the glass plates may be carefully cleaned, and then the whole may be put together almost as quickly as the pieces were taken apart. It consists of two glass plates which are separated by a semi-ring of vulcanized india-rubber.

against which they are squeezed so firmly as to be watertight, by means of two vulcanite plates, evident that the front plate may be made of glass held together by screws with milled heads. It is of any degree of thickness, while the depth of fluid employed may be regulated by the thickness or number of semi-rings of rubber placed between the glass plates. Other points of value will readily suggest themselves to those who are in the habit of using an accessory of this kind.

EXCHANGES.

Diatoms in situ. and free algæ, and other material, animal, vegetable, and mineral, to exchange, by list, for material or mounted objects; A. Booth, Longmeadow, Mass. none but first-class objects offered or desired. M.

Wanted, copy of Micrographic Dictionary, Second Edition, in exchange for Leidy's Rhizopods. etc. A., care Editor this journal.

Contributions to the Extinct Vertebrate Fauna of the Western Territories, by Joseph Leidy. Vol. I, in exchange for a similar work on Botany. F. O. Jacobs, Newark, Licking Co., Ohio.

Over 100 new first-class transparencies for the lantern, to exchange for microscope accessories; a first-class 1-12, 1-4, and 1 inch objective wanted. Box 107, Astoria, L. I.

Beautiful Beryls, Garnets, Tourmalines, Rose Quartz, Muscovite, Granites in variety, etc., to exchange for coins, shells, fossils, minerals, fully. C. Le R. Wheeler, Wilmot, Merrimack Co., books, magazines-anything. Describe offers N. H.

A good microscope, costing $136 in Paris, in ex'Spectroscope." care American Journal Microscopy, 14 Dey Street, N. Y.

The instruments in use during the evening were by R. & J. Beck, and Crouch, of London, and by change for a good working spectroscope. Address Kopler, of Washington, D. C.