"Voted, That the committee to be appointed in pursuance of the foregoing resolutions consist of the gentlemen who reported them; viz. Messrs. Guyot, Agassiz, Peirce, Lovering, and B. A. Gould, Jr.” Professor Agassiz made an oral communication of considerable length upon the classification and homologies of radiated animals. Professor Lovering read a part of a letter from Captain Lefroy, of the Toronto Observatory, to Mr. W. C. Bond, representing that there is danger that the magnetic observations at that place may be discontinued after next March, and expressing a desire that the Academy would use its influence in promoting their continuance for a further period of three years. He then offered the following resolutions, which, after some remarks by Mr. Guyot in their support, were adopted: "1. That, in the opinion of this Academy, it is highly desirable that the magnetical and meteorological observatory at Toronto should be sustained for another period of three years. "2. That a committee be appointed to correspond with the American Minister at London, or with the Royal Society, as they may think best, with the view of urging upon the British government the scientific importance of prolonging their magnetical and meteorological operations in British America, and thus coöperating with similar observations to be made more or less extensively at different stations in the United States." Hon. Edward Everett, Mr. W. C. Bond, Mr. Guyot, Professor Lovering, and Mr. J. P. Hall, were appointed a committee to carry the foregoing resolutions into effect. Professor Lovering made some remarks upon the advantages of the French system of weights and measures over all others, and offered the following resolutions, which were adopted : "1. That the decimal system of weights and measures, based upon the French metre, possesses advantages which belong to no other system that has been adopted or proposed; that it is the only existing sys tem which is symmetrical in its parts, simple in its reductions, and which maintains in its various denominations that invariable and recoverable value which adapts the observations and experiments recorded in it for ready and permanent use over all the world. "2. That the Academy authorize the use of the system in their own publications, and recommend its adoption for scientific purposes wherever it is practicable." On motion of Professor Agassiz, it was 66. Voted, That these resolutions be communicated to other scientific bodies of a similar character to that of the Academy." On motion of Professor Agassiz, it was "Voted, That the Recording Secretary be authorized, with the concurrence of the President, to call a semi-monthly meeting of the Academy at their hall, whenever any Fellows shall have such an amount of scientific matter prepared for communication, as to render a special meeting expedient." Three hundred and thirty-ninth meeting. November 13, 1850.- QUARTERLY MEETING. The PRESIDENT in the chair. The President laid before the Academy two letters, written in the year 1796, by Count Rumford, to the late John Adams, then President of the Academy; among whose papers they were recently found by Hon. C. F. Adams, and by him transmitted to the President. The following gentlemen were elected Members of the Academy : Professor Alexis Caswell, of Brown University. Professor William Chauvenet, of the U. S. Naval Academy, Annapolis. Professor Lovering stated that Part II. of Vol. IV. of the Memoirs of the Academy would be printed in a week or two, and that two papers of the fifth volume were already printed. In accordance with an arrangement made by Dr. Bowditch, the children represented to be Aztecs, from Central America, were exhibited to the Academy. They excited much interest. The boy presented, in the form of his head and the expres sion of his countenance, a striking resemblance to an engraving of a piece of sculpture, found near Palenque in Central America, to which Dr. Bowditch had previously called the attention of the Academy. Three hundred and fortieth meeting. December 3, 1850. MONTHLY Meeting. The PRESIDENT in the chair. Mr. Everett, chairman of the committee appointed at the last monthly meeting to address a letter on the subject of sustaining the Toronto Observatory, either to the American Minister or the Royal Society, as they should deem most expedient, stated that the committee had addressed a letter to the Royal Society, recommending the continuance of the meteorological and magnetical observations at the Toronto Observatory, for another period of three years. Dr. Pierson exhibited to the Academy a large and valuable specimen of gold recently brought from California. Mr. Alger exhibited several very remarkable crystals of gold from California, and offered the following remarks in illustration of them: "The largest were octahedral crystals, simple or modified, and were as perfectly formed as similar crystals of pleisto-magnetic iron, or octahedral spindle. The most striking examples were three isolated crystals, which without exhibited no portion of the usually adhering quartz matrix. Their exact locality was not known, but the very worn appearance presented by several of them indicated their erratic or transported origin. The largest was three fourths of an inch across the base, and the smallest one quarter of an inch. This last presents four regular faces, with three of its solid angles extending out to points, which, however, have become somewhat rounded by attrition. It exhibits no modifications; but two of its faces are depressed or hollowed ot, one of them by a very deep cavity, which extends not quite to the edges of the planes, but so near to them as to leave a narrow ridge or border all around the cavity, and parallel with its edges; thus giving the same triangular outline to each. It appeared as if the crystal had been in a melted state, and that, soon after the outside had congealed, the inner and yet fluid portion, or a part of it, had run out, leaving the surrounding consolidated edge just referred to. Appearances quite similar may sometimes be observed among artificial crystals, as for instance alum, and, more strikingly, metallic lead (which takes the form of the octahedron and has become partially desulphurized), in cases where the metal was allowed to flow off slowly, just as the outer crust had formed over the surface of the crystals. The large crystal presents only one half of the octahedron, its base blending with the massive gold, or only indicating the incipient planes of the lower pyramid. Three of its planes are perfectly smooth, excepting along the edges, which are prominently marked by the same projecting border or ridge observed on the smaller crystal. This border may have been produced in the same manner by the shrinking away of the metal, or it may be the result of that kind of crystallization which is dependent on a greater intensity of molecular attraction in one direction or axis than another. It would seem in this case as if the molecules arrived at the points of contact along the edges of the crystal faster than they could be appropriated, and thus have accumulated in these little ridges. This peculiarity is not confined to the large crystals, for it is observed even among the smallest. In one instance, as shown on a crystal of a half-inch in diameter, there had been produced a double series of these parallel ridges, extending around the edges of one of the planes of the octahedron, the inner ridge representing, apparently, the commencement of another crystalline face within the cavity of the larger one.* "The great size of these crystals, and the fact that some of the cavi * The two large crystals above described were obtained from the very choice and beautiful collection of specimens, made with great care, and at no small expense, by Mr. Platt. This gentleman, during a most prosperous residence of two years in San Francisco, and while occupying a situation which brought him into daily and almost hourly contact with persons returning from the mines, has evinced his good taste by purchasing the most interesting specimens obtained by them. He has consequently been rewarded by the finest amateur collection hitherto brought from California. It comprises a great variety of ramified, arborescent, dendritic, and other imitative forms, here and there showing crystalline faces, all of them being sometimes most fantastically joined together in the same specimen. He informs me that, in obtaining this collection, he had examined gold of the value of more than four millions of dollars. ties contained portions of oxide of iron, probably derived from the decomposition of iron pyrites, have led some to regard them as pseudomorphs of sulphuret of iron. But there seems to be no good reason for ascribing any such forced and unnatural origin to these beautiful productions. On the contrary, they seem to have been formed under the ordinary circumstances of crystallization, either in open space, or while surrounded by a matrix so soft and accommodating, as to allow them full freedom to take the form it was intended they should take. Were the crystals cubes, there might be some reason for regarding them in the light of pseudomorphs of iron pyrites, because this is the most common form of pyrites, and, moreover, all the pyrites hitherto brought from Califor nia have been in that form. But, we may well ask, who has ever seen even a cubic pseudomorph of gold? Crystals of gold are rare, cubes particularly so, and yet this form, on account of its simplicity, is made the primary form; whereas it would seem as reasonable, in cases of the regular system, to select that form as the primary which is most commonly and perfectly presented by the mineral, provided there is no cleavage to guide us in the determination; and there does not appear to be any, well made out, among most of the native metals. By assuming those which most commonly occur in nature, we seem to recognize a sort of inherent disposition, a preference, as it were, which is shown by the mineral itself; and we avoid what seems to be a palpable inconsistency, namely, the establishing of a cube as the primary form of minerals which have never been known to occur under such form, and which even present a distinct octahedral cleavage. This is the case with two at least. If we take the simplest form, the cube should be made the primary of native iron, copper, lead, silver, and mercury; and so of some others, which occur in octahedrons and are not determined by any certain cleavage. In the case of copper, some authors have made the cube its primary.* Haüy (Traité, 1808) even expressed his doubts as to the existence of cubic gold, while he cites examples of the octahedron; and Beudant (Min., 1832) says they are very rare.† Mohs implies the contrary, for he says (Min., ed. * They differ in regard to silver and iron, some adopting the cube, and others the octahedron, as the primary. ↑ Cronstedt, in his Mineralogy, says, "I have procured in Transylvania a specimen of cubic native gold, but I have never seen it anywhere else." In Levy's enumeration of the splendid Turner collection formed by Henry Heuland, eight examples are given of the regular octahedron, and only two of the cube, one of these being from the very locality Cronstedt speaks of. |