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if the new comet may not have experienced perturbations since 1779, which would account for the present want of coincidence in the elements with those of Lexell's comet in the table. If no such considerable deviation from a regular course can be admitted as probable, the hypothesis of identity with the comet of 1770 must be given up.

But if the new comet has experienced considerable perturbations since 1779, these must be calculated before we can pronounce against the suspected identity. As the observations made at one appearance cannot be depended upon as a sufficient foundation for fixing its position for a period of more than sixty years, it became necessary to pursue the same course, in reference to the new comet, which had been followed in regard to Lexell's, and “to determine all the positions which it could have occupied in 1779, and the elements of all the orbits in which it could have moved conformably with the recent observations."

The great complexity and difficulty of the problem undertaken by M. Leverrier are now apparent. He proceeds to solve it by examining the positions and elements of the comet of Faye, in the reverse order of time, during several successive periods, viz. : 1. from 1843 to 1839; 2. from 1839 to 1819; 3. from 1819 to 1814; 4. from 1814 to 1797; 5. from 1797 to 1792.

The paper of M. Leverrier, as transmitted to the American Academy, being itself an abstract of the memoir read to the Academy of Sciences at Paris, hardly admits, in this portion of it, a further condensation, which could not be made without impairing the clearness of the discussion. At the close of the examination of these successive periods, M. Leverrier arrives at the definite conclusion, that the periodical comets of Faye and Lexell are two different bodies.

In concluding the memoir, M. Leverrier briefly considers the question, At what time did the action of Jupiter give to the comet its present orbit? Or rather, What is the least remote time at which this phenomenon may have taken place?

He establishes this least remote period at the year 1747. It is possible that the comet in question may have received, on its approach to Jupiter in that year, the impulse which placed it in its present orbit, and that it was consequently discovered by M. Faye on its thirteenth return.

Professor Peirce read some correspondence between Dr. Gerling of Marburg and Lieutenant Gillis, communicated by the latter, and offered the following resolutions, which were adopted.

Resolved, That, in the opinion of this Academy, the enterprise for determining the solar parallax, in the method proposed in the correspondence between Lieutenant Gillis and Dr. Gerling, is worthy to be promoted by the government of the United States, by sending an expedition to Chiloë, both on account of the great uncertainty which attends the adopted value of this fundamental basis of astronomical measurement, and the probability that this attempt will prove successful, and thus redound to the honor of the country by which it is undertaken.

Resolved, That a copy of the above resolution be transmitted by the Corresponding Secretary to Lieutenant Gillis, with a request that he will communicate it to the public authorities who may have this subject under consideration."

Professor Peirce also reported some of Mr. George P. Bond's observations upon the nebula in Andromeda.

Mr. Paine stated the results of his meteorological observations upon the present extraordinarily mild winter.

Three hundred and fourth Meeting.

January 26, 1848. - QUARTERLY MEETING. The PRESIDENT in the chair.

The Corresponding Secretary read letters of acceptance from the Hon. Abbott Lawrence and Professor Edward H. Courtenay, who were chosen Fellows at the last quarterly meeting.

Mr. Everett read a communication from Professor Nichol, directing attention to certain deficiencies in the meteorological records as printed in the Academy's Memoirs ; whereupon,

some remarks having been made upon the desirability of printing Dr. Holyoke's meteorological journal in extenso, the original manuscript, along with Professor Nichol's letter, was referred to a committee, consisting of Messrs. Hale, Paine, and Gould.

Mr. Everett read extracts from a letter of Professor Schumacher of Altona, stating the conditions required to be observed by the candidates for the medal awarded by the king of Denmark to the discoverers of telescopic comets. As the conditions in respect to the immediate transmission of intelligence to the proper persons are indispensable, and appear not to be well known in this country, Mr. Everett read a translation from the original German, in the Astronomische Nachrichten, No. 400, which, for the sake of wider dissemination, is herewith given in the subjoined note.*

A gold medal of 20 ducats' value was offered by the predecessor of the late king of Denmark to the discoverer of a telescopic comet. This foundation was confirmed by the late king, by whose authority the following regulations were established:

1. The model will be given to the first discoverer of any comet, which at the time of its discovery is invisible to the naked eye, and whose periodic time is unknown.

2. The discoverer, if a resident in any part of Europe except Great Britain, is to make known his discovery directly to Mr. Schumacher at Altona. If a resident in Great Britain, or any other quarter of the globe, except the Continent of Europe, he is to make his discovery known directly to Mr. Francis Baily, Lon. don. — (Since Mr. Baily's decease, G. B. Airy, Esq., Astronomer Royal, has been substituted in this and in the 7th and 8th articles of the regulations.]

3. This communication must be made by the first post after the discovery. If there is no regular mail at the place of discovery, the first opportunity of any other kind must be made use of, without waiting for other observations. Exact compliance with this condition is indispensable. If this condition is not complied with, and only one person discovers the comet, no medal will be given for the discovery. Otherwise, the medal will be assigned to the discoverer who earliest complies with the condition.

4. The communication must not only state as exactly as possible the time of the discovery, in order to settle the question between rival claims, but also as near as may be the place of the comet, and the direction in which it is moving, as far as these points can be determined, from the observations of one night,

5. If the observations of one night are not sufficient to settle these points, the annunciation of the discovery must still be made, in compliance with the third

Messrs. Edward Desor and Charles Jackson, Jr., were elected Fellows of the Academy.

Professor Spencer F. Baird, of Carlisle, Pennsylvania, was elected a Corresponding Member.

Three hundred and fifth Meeting.

February 1, 1848. - MONTHLY MEETING. The PRESIDENT in the chair.

Professor Horsford read extracts from a letter from Professor Liebig, communicating the results of some experiments made with a view to determine the permeability of membranes to air, water, and various solutions. He has arrived at the conclusion, that the secretions from the blood-vessels and alimentary canal are directly produced by the evaporation from the skin and lungs, on the one hand, and the pressure of the atmosphere on the other.

Professor Horsford also made the observation, that chloroform, and several other compounds which taste sweet, may be written in the list of the various sweet bodies enumerated in his paper upon Glycocoll. To illustrate this he presented the following formulæ :

66 Sweet Bodies.

C, H,0 0,0 = Milk Sugar.
C, H, 0,1 = Cane Sugar.
C, H,2 0,2 = Grape Sugar.

article. As soon as a second observation is made, it must be communicated in like manner with the first, and with it the longitude of the place where the dis. covery is made, unless it take place at some known observatory. The expecta. tion of obtaining a second observation will never be received as a satisfactory reason for postponing the communication of the first.

6. The medal will be assigned twelve months after the discovery of the comet, and no claim will be admitted after that period.

7. Messrs. Baily and Schumacher are to decide if a discovery has been made. If they differ, Mr. Gauss of Göttingen is to decide.

8. Messrs. Baily and Schumacher have agreed to communicate mutually to each other every announcement of a discovery.

Altona, April, 1840.

C, H, O, =of Grape Sugar.

H
C, H, H 0,

0

H
C4 H, H 0 = Sugar of Glue. Glycocoll.

N

H н
C, H, Pb 02 = Sugar of Lead.

O

0
C, H, Pb 02 = } Citrate of Lead.

0

H
C, H, K 03 = Acetate of Potassa.

O

H
C, H, H O3, H, 0,= Nitric Ether.

N

H
C, H, H Og = Glycerile oxide.

H; O

CI
C, H, CI Cl2 + 2 = Chloroform.

CI

Br

C, H, Br Brz ; 2= Bromoform.*

Br

I
C, H, I Iz + 2 = Iodoform.

I

I
C, H, I Cl2 + 2 = Chloro-iodoform.

CI

Br
CH, Br 1, 2 = Bromo-iodoform.

I
H

H
C, H, H • 2 =
F1,

Hydrofluate of Methylene. H * For the observation that this and the following four bodies may be included in the series, the author is indebted to his friend Dr. Peirce, of the Cambridge Laboratory.

+ The hydrofluate of methylene has a pleasant ethereal smell.

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