6. Double Stars observed at Cambridge Observatory.-1848-49. Name of Star. Date. A. R. h m. Dec. Pos. Dist. 170 P. VII. a2 Geminorum 1848.27 7 325 36 142 40 1848.30 7 24+32 14 249 45 1.3 4 140 B' The two components make a star of the 7th or 8th magnitude. 860 B1 A= 1st, 2d, B = 3d. 860 B1 860 B2 860 B A and B. 860 BA and C. 860 B' A= 4th, B= 5th, 6th. 860 B2 860 B2 860 B Seen through dense clouds; the definition is good. 860 B2 860 B1 The images of the stars are pretty well defined, though not good. 860 B2 A= 3d orange, B = 7th green. 860 B2 A= 3d golden, B = 7th blue or greenish. 5.1 5.3 3.2 5 860 B2 .55 240 00 4.3 860 B' .54 239 30 4.3 5 860 B' 1240 B2 Not a favorable evening for close objects, but the components are separated with 400 BA 1st, B=10th. [certainty. 277 00 38 3 400 B2 OF ARTS AND SCIENCES. 1560 B2 Very fine definition. 5 860 B1 5 860 B Bad definition. 860 B1 B2 .41 211 20 115.1 5 .41 212 30 118.1 5 140 B2 5 140 B1 3 860 B The position-angle does not agree with its computed value. 860 B1 A= 3d, B=8th. 6.9 5 1560 B'A=4th, B 6th. B has a reddish tinge. 117 45 6.8 5 1560 B2 1848.56 16 23+2 18 9.50 1.4 10 1848.40 16 51 -12 39 212 30 115.6 212 30 115.2 211 57 115.4 211 13 116.1 860 B When the micrometer-wires are set at 1", both wires are decidedly within the stars. 220 BA=6th, B=15th. A resembles Antares to the naked eye, but its red is deeper. 140 B1 [It is one of the most strikingly colored stars we remember to have seen. On the 29th of June this star was seen with thirty companions of from the 15th to the 20th magnitudes, within a radius of 6. 140 B2 With a power of 1500 there is no sign of a planetary disk under fine definition. 140 B2 A=7th, 8th, B= 14th. A appears to have decreased in brilliancy; its ruby-red color still remains. The star is at once recognized from its neighbours by its color alone. 320 B2 A=7th, 8th, B= 15th. A is sensibly less than when first seen. 400 B1 140 B' Longer axis of the ring. 140 B Shorter axis. Companion star 12th magnitude. Seeing not good. Three hundred and seventeenth meeting. The PRESIDENT in the chair. The Vice-President, Mr. Everett, read a letter from Professor Schumacher, of Altona, inclosing printed copies of a communication from the Secretary of the Royal Astronomical Society at London to Lord Palmerston; also letters from M. Arago and from Baron Humboldt; touching the position of Professor Schumacher in his connection with the observatory at Altona, and as the publisher of the Astronomische Nachrichten, and the dangers that threaten them in consequence of the disturbed state of the relations between Denmark and the Duchies of Schleswig and Holstein. Whereupon it was unanimously "Resolved, That the American Academy of Arts and Sciences entertains a high opinion of the importance of an observatory at Altona, as a convenient point of communication between countries distant from each other, and of the value of the Astronomische Nachrichten as a medium of intelligence for the whole scientific world; that it recognizes the great importance of Professor Schumacher's services in connection with the Altona observatory and the publication of the Nachrichten, and would regard as a public misfortune any event which should interrupt his labors, or discourage the generous zeal with which, during a long and honorable career, he has successfully exerted himself for the promotion of astronomical science. "Resolved, That a committee be appointed to address a letter to Professor Schumacher, transmitting a certified copy of these proceedings; and that a copy of the letters this evening submitted to the Academy be sent by the committee to the other learned societies and observatories of the United States." Mr. Everett, Professor Peirce, and J. Ingersoll Bowditch were appointed to constitute this committee. Professor Peirce, after calling attention to a recent communication in Silliman's Journal, on the trisection of angles, exhibited an instrument for this purpose, which was devised many years ago, by the late B. R. Nichols, Esq. He also ex hibited the model of another instrument, constructed by Mr. Nichols, for the division of an angle into any number of equal parts. Professor Peirce also presented the computation of the orbit (elliptical) of Petersen's comet, made by young Safford, now thirteen years of age, showing its period to be 382,000 years. He stated that Safford was employed only fifteen hours in the computation. Professor Peirce likewise made a communication, in which he gave reasons for his belief that all the comets seen by us are component parts of our solar system, drawn from the fact that their orbits are none of them decidedly hyperbolical. He showed that few comets could enter the solar system except in orbits of a manifestly hyperbolic form, derived from the motion of our system in space. Three hundred and eighteenth meeting. April 4, 1849. MONTHLY MEeting. The PRESIDENT in the chair. Mr. Everett read a letter from M. Leverrier, in relation to the discovery of the eighth satellite of Saturn. He also exhibited the comet-medal awarded by the king of Denmark to Miss Mitchell, which had just been received, and presented a printed copy of the correspondence which had been held in relation thereto. Professor Peirce read a letter from Mr. S. C. Walker, containing a comparison of his ephemeris of Neptune with the latest observations on that planet, showing a variation from his calculations of only the fraction of a second. He also adduced further reasons for his opinion that the known comets belong to our solar system, drawn especially from the tendency of their orbits in respect to the plane of the ecliptic. His attention. had been drawn to the obvious error of Laplace's argument upon this point by Dr. B. A. Gould, Jr.; who has made a chart of the path of the orbits of the comets, which is conclusive in its exhibition of the relation of the comets to the solar system. Dr. J. C. Warren and Dr. Channing continued a discussion which commenced at the last meeting, on the comparative merits and safety of ether and chloroform as anæsthetic agents. Three hundred and nineteenth meeting. May 8, 1849.-MONTHLY MEETING. The PRESIDENT in the chair. The Corresponding Secretary presented a memoir from William S. Sullivant, Esq., entitled "Contributions to the Bryology and Hepaticology of the United States, Part II.,” comprising the descriptions of several new or little known Musci and Hepaticæ, illustrated by figures. Professor Agassiz gave a summary account of his investigations upon Medusæ. He has ascertained that their body consists entirely of cells, preserving in all the different systems of organs their character as true cells, and nevertheless performing very different functions. He showed that there is a complete system of bundles of elongated cells, arranged in longitudinal and transverse series, acting as muscles, and disposed in several layers, one being superficial and another lining the inner surface of the disk in Discophora, whilst some penetrate at various depths the gelatinous mass. The nervous system consists of a circular cord of oval cells, extending along the lower margin of the disk, from one eye-speck to the other, and forming a ganglion at the base of each. He also showed that the digestive system is naturally distinct from the tubes through which the digested food, mixed with water, is circulated, though at times they communicate directly with each other. This circulation - the arrangement of which he has ascertained by artificial injection-is very complicated in |