Samuel B. F. Morse, Esq., of New York, and Professor Wolcott Gibbs, of New York, were elected Fellows.

From the list reported by the Council appointed for this purpose, the following persons were chosen Foreign Honorary Members, viz. :

Robert Brown, Esq., London.

Prof. Elias Fries, Upsal, Sweden.
Leopold von Buch, Berlin.

Sir Henry de la Bèche, London.

Prof. Elie de Beaumont, Paris.

Prof. P. A. Hansen, Seeberg, Denmark.

Prof. Jens Christian Oersted, Copenhagen.

Prof. Henry Rose, Berlin.

Prof. Jean Baptiste Dumas, Paris.

Prof. Milne Edwards, Paris.

Prof. Johann Müller, Berlin.

Prof. Christ. Gottfried Ehrenberg, Berlin.

Prof. Karl Ritter, Berlin.

Prof. Friedrich Tiedemann, Heidelberg.

Prof. Theod. Ludwig Wilhelm Bischoff, Giessen.

Prof. Johann Friedrich Encke, Berlin.

Prof. Karl Ernst von Baer, St. Petersburgh.

Prof. Theod. Schwamm, Louvain, Belgium.
Robert Stephenson, Esq., London.

M. Benoit Fourneyron, Paris.

Prof. Macedonie Melloni, Pisa.

M. Andral, Paris.

Prof. P. C. A. Louis, Paris.

Three hundred and twenty-fifth meeting.

December 4, 1849.-MONTHLY MEETING.

The PRESIDENT in the chair.

The occasion was rendered peculiarly interesting from the circumstance that the meeting was convened in the library of Dr. Bowditch, formerly President of the Academy. The

arrangements of the apartment remain precisely as they were in his day. His chair and table occupy their usual position, his bust is placed on the wall as near as possible to the place where he used to sit, and all the papers on his desk remain just as he left them. Many incidents respecting his

early life and his subsequent habits, and especially his scientific labors, were related, and several memorials were shown, - such as medals; a bust of Laplace, presented by his widow; the manuscript of an Almanac, constructed by him at the age of fifteen; his abstract of the mathematical papers in the Transactions of the Royal Society; his portfolios, on the covers of which were numerous mottoes in various languages, characteristic of the philosopher; and, lastly, the fragment of his translation of the fifth volume of the Mécanique Céleste, as far as he had proceeded.

Letters were read from Samuel B. F. Morse, Esq., and Professor Wolcott Gibbs, of New York, accepting the fellowship of the Academy.

Dr. H. I. Bowditch gave the result of the microscopic examination of the accumulations on the teeth of healthy persons, near the gums, in forty-nine individuals, most of whom were very particular in their care of the teeth. Animalcules and vegetable products were found in every instance except two. In those cases the brush was used three times a day, and a thread was passed between the teeth daily. Windsor soap was also used by one of these two persons, with the brush. Dr. Bowditch had tried the effects of various substances in destroying the animalcules, and especially of tobacco, by which they seemed to be in no wise incommoded. Soap-suds and the Chlorine Tooth-wash invariably destroyed them.

Professor Agassiz made some remarks on the egg in vertebrate animals, as a means of classification. What is their structure, and is there any thing specific in the eggs of the different classes of Vertebrata? In the eggs of them all is found a generation of cells in the germinative dot, as may be readily

seen in eggs of turtles, rabbits, squirrels, &c. The eggs of Mammals are very minute, and surrounded by epithelium; and they begin at once their subdivision within the parent. In those of birds, a large bulk of vitellus is developed in the ovary, and afterwards the albumen and shell are added. The same is the case in turtles, lizards, and serpents; but the eggs of Batrachians are different, and are small, elastic, and dilatable, like those of fishes. He thought, therefore, that there was a closer affinity between the first-mentioned reptiles and birds than between them and the Batrachians; and that the turtles, lizards, and serpents might be incorporated with birds, while the Batrachians were classed with fishes.

Professor Horsford exhibited several specimens of vermilion which varied very essentially in color from adulteration. Some of the articles used for that purpose are chromate of lead, sulphate of lime, and carbonate of magnesia.

Mr. Desor mentioned some facts relating to the distribution of animals in the region of Lake Superior, and specified some of the animals found on Isle Royale, whose presence he was at a loss to account for, except on the supposition that the island was once continuous with the continent.

Three hundred and twenty-sixth meeting.

January 8, 1850.- MONTHLY MEETING.

The PRESIDENT in the chair.

Dr. C. T. Jackson, from the committee raised at a former meeting to suggest a practicable mode for recording by coastmarks the present mean sea-level on the Atlantic shore of this country, made a report, in the form of a memorial to the Secretary of the Treasury. The draft was recommitted, in order that a proper resolution, expressing the sense of the Academy, might be appended.

Mr. Paine presented a communication from Professor Augustus W. Smith, of Middletown, Connecticut, containing

Occultations of Fixed Stars, &c., at the Wesleyan University, Middletown, Connecticut. Latitude, 41° 33′ 10". Assumed Longitude, 4h. 50m. 36..

* This observation was supposed to be good at the time, and no error can be found by referring to the original entry in my book of rough records. But a reduction of the observation for this longitude leads to the supposition that it ought to be 2b. 20m. 30.08s..

Professor Lovering read the following communication, viz.:

"Remarks on the Aneroid Barometer, by PROFESSOR J. LOVERING, of Harvard University.

"Most of the scientific journals of Europe and America have published descriptions of the new French barometer, as it is called. For the construction of the instrument, and the history of its invention, I may refer to them; and particularly to that contained in Silliman's Journal for September, 1849.

"The two ordinary statical ways of measuring forces are, first, by means of gravity, and, second, by means of elasticity. Our common balances to measure weight employ, either the gravity of a known counterpoise, or the elasticity of a spring. In like manner, the weight of a column of the atmosphere is determined by ascertaining the height of a similar column of some known fluid, which it is able to support, or the elasticity of some familiar substance with which it is in equilibrium. The barometer with which we are most familiar employs the first method: the aneroid barometer, which, as its name implies, contains no liquid, is based on the last principle, namely, that of measuring weight by elasticity.

"This new instrument is already manufactured, in large numbers, in France and Great Britain; and its adoption is recommended on the ground of economy, as well as of its great compactness. The barometer is now extensively used, not only for tracing out the grand laws of meteorology, but also as a practical guide to the mariner to forewarn him of approaching storms, and an indispensable auxiliary to the man of science in studying the geography of the solid parts of our planet. It is highly important that the meteorologist, the navigator, and the student of general science, should know what degree of accuracy may be claimed for the new barometer, and to what extent they are allowed to trust themselves to its indications. With the hope of assisting those who desire to form an opinion on this subject, I present the following experiments and observations, undertaken originally at the suggestion of Professor A. D. Bache, Superintendent of the United States Coast Survey. The instrument employed in this research was furnished by Professor Bache. It bears the number 1265, and came from the establishment of Lerebours and Secretan, Paris.