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through the telegraphic circuit between Washington and St. Louis, seventeen hundred miles in length. His experiments gave a velocity of a little less than ten thousand miles a second. This result he proposes to test by further experiments on telegraphic lines, in which chemical changes of colors are used, instead of markings made by an electro-magnet. Mr. Walker found that pauses and syllables could be simultaneously transmitted in opposite directions, without interference, in the telegraphic circuit, in the same manner as they are in air.

Professor Agassiz stated that he had ascertained that there are certain animals, capable of performing all the great functions of animal life, which consist entirely of cells. He referred, in illustration of his remark, to the genus Coryne of the Polypoid Medusæ, found in Boston harbor. He distinguished the cells of which the tentacles of these animals are composed into three kinds, - epithelian, lasso, and locomotive cells. The tentacles, which consist of two cylindrical bodies, one within the other, tapering to a point, and without any cavities, are composed entirely of such cells. The epithelian cells cover the whole surface of the tentacles. The individual lasso cells throwing out their inner cylindrical body, the tentacles are converted into stems, with long, lateral threads, for catching small animals. By the contraction of their inner or locomotive cells, they are reduced to one tenth of the length they have when elongated. The locomotive cells were stated by Professor Agassiz to undergo endosmosis and exosmosis, accompanied by a change of form in the individual cells which constitute the inner cylinder of the tentacle, and in that change, to become organs of locomotion. The apparent fibres, described by some writers, were said by Professor Agassiz to be merely elongated cells.

Professor Peirce and Dr. Walter Channing made some further remarks in regard to the cause of the elongation of the cells.

After a discussion of considerable length, in which Mr. Guyot, Mr. B. A. Gould, Jr., Professor Agassiz, and the President took part, on the importance and practicability of introducing a uniform system of thermometrical and barometrical notation in all countries where science is cultivated, it was, on motion of Mr. Guyot, —

Voted, That a committee be appointed to consider the expediency of recommending the adoption of the centigrade thermometrical scale, and the metrical barometrical scale at the meteorological stations in Massachusetts.

Voted, That Mr. Guyot, Professor Agassiz, Professor Peirce, Professor Lovering, and Mr. B. A. Gould, Jr. be that committee."

Professor Agassiz made some remarks respecting the structure of the egg. He stated that no two portions of the egg between the centre and the periphery have the same structure ; that the yolk does not consist of homogeneous cells; and that it is not a store of nutritious matter to feed the young animals, but that it is a living, organized being.

On motion of Professor Peirce, it was voted that a monthly meeting of the Academy be held on the first Tuesday in August, at four o'clock, P. M.

On motion of Mr. B. A. Gould, Jr., it was

Voted, That a committee be appointed to address a memorial to the Senate and House of Representatives of the United States, on the subject of attaching a corps of scientific men to the commission for running the boundary line between the United States and Mexico.”

Professor Agassiz, Professor Peirce, and Mr. B. A. Gould, Jr., were appointed a committee for that purpose.

Three hundred and thirty-fifth meeting.

August 6, 1850. — Monthly Meeting. The PRESIDENT in the chair.

The Corresponding Secretary read a letter of acceptance from Professor Bischoff of Giessen, recently elected a Foreign Member of the Academy.

Professor Agassiz communicated a paper on Spermatozoa by Dr. Burnet, of which he gave a brief abstract. He highly commended the paper, as establishing new and important views, and evincing uncommon qualifications on the part of its author for such researches.

On motion of Professor Agassiz, it was referred to the Committee of Publication.

Professor Agassiz stated that he had ascertained that catfishes, and the whole family of Siluridæ, to which they belong, have a sub-cutaneous cavity behind the humerus, and outside of the peritoneum and the muscular walls of the abdomen, into which protrude portions of the liver, and sometimes the air-bladder and kidney. He also stated that these animals have lateral holes for the admission of water into the interior of their bodies.

Professor Agassiz exhibited a part of the skin of a Bonito, caught off Nahant, which presented a remarkable peculiarity in the form of its scales. At first sight, the animal seemed to offer the anomalous phenomenon of ctenoid and cycloid scales occurring upon the same individual ; but, on further examination, the scales were found to be a new type, intermediate between the ctenoid and the cycloid, the serratures being merely marginal, and not extending over the posterior surface. He also called attention to some dark, longitudinal stripes, which at first appeared to militate with the views he had brought before the Academy at a late meeting, respecting the connection between the coloration and the structure of animals. On examining them more carefully, however, each stripe was found to originate at the base of one of the finlets of the tail.

Professor Agassiz, in reply to a question of the President, stated that the shrill noise heard on suddenly drawing a catfish out of the water is occasioned by the escape of air from the air-bladder through the pharynx ; and, in reply to a remark of Dr. Gould, he stated that a somewhat similar explanation is applicable to the noise made by the drum-fish

when taken from the water, a fact recently ascertained by Dr. Holbrook.

Three hundred and thirty-sixth meeting.

August 14, 1850. — QUARTERLY MEETING. The President in the chair.

The Corresponding Secretary read a letter of acknowledge ment from Professor Karl Ritter of Berlin, in reply to a notification of his election as a Foreign Member of the Academy.

On motion of Mr. Treadwell, it was voted, that Jonathan P. Hall be appointed Meteorological Observer of the Academy on the Rumford foundation.

The nomination list was taken up, and the following gentlemen were elected Fellows of the Academy :

Josiah D. Whitney, United States Geologist.
Hon. John C. Fremont, of California.
Prof. Stephen Alexander, of Princeton, N. J.
Prof. J. S. Hubbard, of Washington, D. C.

On motion of Professor Peirce, it was voted, that the next statute meeting be held in the evening.

Three hundred and thirty-seventh meeting.

October 1, 1850. — Monthly MEETING. The PRESIDENT in the chair.

The Corresponding Secretary laid before the Academy letters from Professor Encke of Berlin, and Professor Müller, also of Berlin, signifying their acceptance of the honor conferred upon them by the Academy in electing them Foreign Honorary Members.

Professor Horsford presented a communication upon the spheroidal state of bodies. He proposed to show that temperature is not essential to the production of the phenomenon in some cases, and that no new law is required for its explanation

in any case. He referred to the act of plunging the moistened hand into masses of molten metal as coming under this head, and as having been repeatedly performed in this country more than twenty years ago. The explanation he gave of the safety of the hand in this exposure was, that the moisture, volatilizing, rendered a part of the heat latent, and encased the hand in a sheath of aqueous vapor, so that only radiant heat acted upon it, and that only for the instant the hand was immersed.

As proof of the occurrence of the spheroidal state in the absence of temperature, Professor Horsford instanced the form mercury assumes on glass, that of oil and ether on water, and the bead upon acohol when agitated. The explosion at the close of the experiment of burning potassium or sodium on water, especially where the piece is large, he ascribed to the same cause as the explosion in the Leidenfrost experiment, where the cooling of the highly heated surface permits contact. The explosion attending the contact of fused saltpetre and water he classed with the Leidenfrost experiment. That which sometimes takes place when potassium is thrown into water or nitric acid, but an instant after the contact, he ascribed to another cause, – the mixture of hydrogen from the decomposed water, and oxygen from the air or acid, in such proportions as to be explosive.

Professor Horsford expressed a doubt whether any explosions of steam-boilers were to be ascribed to the Leidenfrost phenomenon, alleging that the temperature of 300°, which is about the temperature permitting contact, cannot produce sufficient steam from within the boiler to effect an explosion.

Professor Horsford concluded his paper with a series of experiments illustrating the general subject.

Professor Peirce stated that he had obtained from some investigations connected with the turbine wheel the following result :— that the curve along which a material point should move so as to compel this curve to raise weights to which it is attached, must be the cycloid. He exhibited a drawing

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