tions of an inch and at the same time determines the power of the microscope itself.

4. Geological Survey of California.-The Act of the California legislature (approved April 24, 1860) appoints Prof. J. D. Whitney State Geologist with a salary of $6000 per annum. He appoints his own assistants with the approval of the Governor. Twenty thousand dollars are appropriated to the payment of expenses incurred in the survey. The provisions of the Act respecting the annual and final Reports are eminently judicious, especially that part which directs the Governor and Secretary of State to cause the volumes of the geological survey to be sold for the benefit of the Common School fund of the State.

No state geological survey was ever more auspiciously inaugurated, wisely provided for, or fraught with more interesting scientific and practical problems. It is understood that Prof. Whitney will commence his Californian labors in the coming autumn.

5. Total Solar Eclipse of July 18, 1860.-The American Nautical Almanac Commission has sent three observers to the Cumberland House, British America, to take note of this eclipse. This is a station of the Hudson's Bay Company on the West side of Pine Island Lake, in lat. 54° N., long. 102° 40' W.

Another party of observers, consisting of Prof. Stephen Alexander, of Princeton, N. J., President F. A. P. Barnard, of Oxford, Mississippi, Prof. C. S. Venable, of North Carolina, Prof. A. W. Smith of the Naval Academy, Annapolis, Md., and Lieut. E. D. Ashe, R. N., of the Quebec Observatory, embarked June 28th at New York in the U. S. steamer Bibb, Lt. Commanding Alex. Murray, to proceed to Cape Chadleigh, Labrador.

6. Newport Meeting of the American Association for the Advancement of Science. The next meeting of the Association will be held at Newport, R. I., commencing on Wednesday the first of August. The officers of the meeting are: President, Isaac Lea, Esq. of Philadelphia; Vice President, Dr. B. A. Gould of Cambridge; General Secretary, Prof. Joseph LeConte of Columbia, S. Ca.; Treasurer, Dr. A. L. Elwyn of Philadelphia.

It will be remembered that Prof. Henry, at the request of the Association, will deliver a discourse commemorative of the life and scientific labors of Dr. ROBERT HARE. Prof. Bache will also by appointment give an address on the Gulf Stream; while Prof. Leidy was requested to prepare a discourse on the extinct Reptilia and Mammalia of North America. There are many reasons why this may be looked forward to as one of the most attractive and promising meetings of the Association ever held. 7. Letter from John McCrady, Esq., Charleston, on the Lingula pyramidata described by Mr. W. Stimpson, vol. xxix, p. 444.-DEAR STIMPSON: I believe you are connected with the Zoological department of Silliman's Journal during the absence of Prof. Dana. You have also, I see, redescribed there our Lingula, long known to naturalists but not before described. It was found more than ten years ago on our coast by the Rev. Thomas J. Young. A living specimen was also found by Mr. Burkhardt on Sullivan's Island when Prof. Agassiz had a laboratory there. I have never seen a specimen during all the time I have resided on Sullivan's Island. I am very glad you have distinguished and described it, since I suppose the Beaufort species can hardly be different from the South Carolinian.

I have found quite lately something very interesting in connection with this Lingula pyramidata. You know that up to this time nothing has been known to science of the development of the Brachiopoda. I have within a few days discovered an embryo unlike anything known, and which has at once so many affinities with the Bryozoa and the Brachiopoda, that I believe it to be an embryo Brachiopod, and very probably the young of Lingula pyramidata. Imagine an equilateral, thin, hyaline, straight-hinged bivalve shell, elliptical in outline, and with valves very flat. Through this perfectly transparent shell is visible a lining membrane or rather the borders of such a membrane, which is the mantle. Within this and near the hinge, a large flask-shaped body containing a digestive cavity surrounded by a dark mass. This cavity extends into the neck of the bottle shaped cavity (œesophagus) and terminates towards the gap of the shell in a mouth. From the opposite or basal end of the digestive cavity goes off a pretty long intestine which turns first to the left, makes several convolutions and terminates in an anus on the right side between the two valves of the shell. The mouth lies on a somewhat triangular prolongation of the body-wall which rests with its apex towards the gap of the shell in the dorsal valve. The borders right and left of this homologue of the arms are fringed each about six cirrhi, the hindermost being the longest.

The animal thus constituted, when quiet withdraws its whole body, cirrhi and all, within its bivalve shell, which is tightly closed; but when in motion the shell is distinctly opened and the gap of the valves is plainly visible even to the naked eye. Through their aperture are thrust out the cirrhi, about twelve in number, which then arrange themselves in circular funnel-like manner precisely as in a Bryozoan polyp, and by a motion plainly ciliary, and with its cirrhi or tentacula thus extended the embryo swims through the water with considerable rapidity.

The cirrhi of this embryo I take to be the homologues of the cirrhi of Brachiopoda, and of Cristatella, and of the tentacula of Bryozoa generally. The rest of the structure, especially the anus on the right and the shape of the shell, point, I think, to Lingula embryo with cirrhi extended about a line in length. There is no trace of a peduncle. It appears to me that this must set at rest all difficulty about the approximation of Bryozoa and Brachiopoda, as proposed by Agassiz and others. A somewhat fuller description of this young animal, with a figure, will be published in the forthcoming issues of the Elliott Society of Charleston. Charleston, S. C., June 18th, 1860.

8. The Fusion and Casting of Platinum on a considerable scale has been accomplished by Messrs. Deville and Debray. At the sitting of the Académie des Sciences at Paris, June 4, they exhibited (1.) Two ingots of platinum weighing together 25 kilograms, fused in the same fire and cast in an ingot mould of cast iron. The surface of the metal shows evidence of perfect fluidity and carries the impression of characters engraved on the surface of the mould.

(2.) A toothed wheel, of platinum cast in ordinary founders' sand was also shown. This was cast in the mode common for cast iron in a twopart flask with a sprue and vent holes as usual.

The metal used they obtained by the dry mode from the crude platinum and platinum-money which the Russian Government had placed at their disposal; the details of the process being reserved for a second communication to the Academy.-Comptes Rendus, June 14, 1, 138.

9. New Arctic Expedition by Dr. I. I. HAYES.-Dr. Hayes, well known as the companion of Kane and the author of "An Arctic Boat Voyage," leaves Boston in a small vessel with seventeen companions for Smith's Sound, early in July, designing to test the views respecting the open sea which he has already expressed in detail in this Journal in an article entitled "Observations on the practicability of reaching the North Pole." This new expedition of Dr. Hayes is equipped by private liberality, and goes out under the auspices of the American Geographical Society.

In this connexion we may mention the proposal of Mr. PARKER SNOW of London, well known for his Arctic researches, to set on foot a new exploration to search for further traces of the Franklin Expedition. Mr. Snow has prepared a paper setting forth his plans and motives in detail, a сору of which we have received and placed before the American Geographical Society at a late sitting, by whom it has been officially communicated to Dr. Hayes, just on the eve of his departure.

10. Constitution and By-Laws of and List of Officers and Members of the Chicago Academy of Sciences. Chicago, Illinois, 1859.-This flourishing young association of naturalists was organized in 1857, and incorporated March, 1859. Its establishment affords another gratifying proof of the rapid progress of science at the West.

11. Personal.-Prof. A. D. BACHE, Superintendent of the U. S. Coast Survey, was recently chosen a Foreign Member of the Royal Society of London. Of the fifty foreign members, three are now Americans, viz., Professors Peirce, Agassiz, and Bache.

Prof. DANA has been in Switzerland since early in May, and will remain among the mountains until his return, toward the close of summer. His health is slowly but steadily improving.

Prof. BENJAMIN PEIRCE, of Cambridge, has sought relief from his too severe labors in a voyage to Europe by packet. His numerous friends will be pained to learn that his health was much impaired.

Prof. J. P. COOKE, of Cambridge, lately read before the Chemical Society of London a paper on the compounds of antimony and zinc (SbZn2 SbZn), designed to show that crystalline form is not a necessary indication of definite chemical composition. A copy of this paper from the Author reached us at too late a date for publication in the present number of this Journal.

The gold medals of the London Geographical Society have been awarded (May 28), at the suggestion of Sir R. I. Murchison, to LADY FRANKLIN and SIR LEOPOLD MCCLINTOCK;-to the first in consideration of the deeds of her husband and in recognition of her noble-minded devotion; and to the second for his discovery of the fate of the Erebus and Terror and the accompanying additions to Arctic geography.

LADY FRANKLIN is announced as expected soon to arrive in the United States as the guest of Henry Grinnell, Esq., Vice-President of the Amer ican Geographical Society.

* Vol, xxvi, No, 78, 805, Nov. 1858.

12. To our Correspondents we owe an apology for the unavoidable postponement to a succeeding Number of several valuable papers, crowded out by the unexpected length of the Articles in the present issue. Even the addition of a full sheet has not sufficed to embrace our customary lists of new books, or a considerable mass of scientific intelligence, proceedings of societies, bibliography, &c., already in type.

13. Obituary. The Rev. BADEN POWELL, Professor of Geometry in the University of Oxford and equally distinguished as a mathematician and physicist, died there in June.

CHARLES GOODYEAR, widely known as the discoverer of "vulcanization" of Caoutchouc died in New York, July 1st, aged fifty-nine years.

CANADIAN NATURALIST AND GEOLOGIST, Dec., 1859. Vol. IV.-p. 411, Notes on land and sea birds observed around Quebec; J. M. Le Moine.-p. 414, Chemical Geology; Hunt.-p. 426, Fossils of the Chazy limestone, with new species; Billings. -p. 494, A list of the Coleoptera found in the vicinity of Montreal; D'Urban.Feb. 1860, Vol. V. p. 1, Devonian plants of Canada; Dawson.-p. 14, List of plants found near Prescott, C. W.; Billings.—p. 24, Tubicolous Marine Worms of the Gulf of St. Lawrence; Dawson.-p. 30, Marine Algæ; Kemp.-p. 69, Palæozoic fossils; Billings. April.-p. 81, Natural History of the Valley of the River Rouge; D'Urban.-p. 100, Review of Darwin; Dawson.-p. 120, Sketch of the life of Mr. David Douglas.—p. 132, On the Silurian and Devonian rocks of Nova Scotia; Dawson.-p. 144, New fossils from the Silurian of Nova Scotia.

PROCEEDINGS PHILADELPHIA ACAD. NAT. SCI., 1860.-p. 81, Notice of the death of Dr. Hallowell.-p. 82, Habits of an Ocelot kept on ship-board; Wilson.-p. 85, Corrected numbers of Unionidae; Lea.-On Hyalonema mirabilis from Japan; Leidy. -p. 86, Donation of 28,000 specimens of birds, by Dr. T. B. Wilson.-p. 88, On the coloring matter of the Nacre in Uniones; Lea.-p. 89, New South American Unionidae; Lea.-p. 92, New Uniones and Melania; Lea.-p. 93, New Cretaceous fossils from New Jersey; Gabb.-p. 96, Experiments in chemical geology; Lesley. -On Trichina spiralis; Leidy.-p. 97, On the palpi of S. American Anodons; Lea. -On a gneiss boulder in Orange Co., N. Y.; Lesley.-p. 98, New botanical locality; Leidy. On the Albertite of New Brunswick; Rogers.-Experiments in Binocular Vision; Rogers-p. 100, Conspectus piscium, etc., the Sicydianæ collected on the North Pacific Expedition; Theo. Gill.-p. 102, Monograph of the genus Labrosomus, Sw.; Gill.-p. 108, Monograph of the genus Labrax, Cuv.; Gill. (Mr. Gill finds our American species generically distinct from the European type. Our striped basse he places in the genus Roccus, and the white perch in Morone-names adopted from Mitchell.)-p. 120, Monograph of the Philypni; Gill.-p. 126, Notice of geological discoveries made by Capt. J. H. Simpson; Meek and Engelman.-p. 132, Catalogue of Birds collected on the Isthmus of Darien by the expedition under Lt. Michler, with notes and descriptions of new species; Cassin.

JOURNAL OF THE ACADEMY OF NATURAL SCIENCES OF PHILADELPHIA, New Series, Vol. IV, Pt. III, March, 1860.-Descriptions of Edotic Unionidæ, 13 plates; 1. Lea. -New Cretaceous and Eocene fossils from Mississippi and Alabama (2 plates); T. A. Conrad.-New Cretaceous and Triassic fossils (a plate); Gabb.-Reflections upon the nature of the temporary star of the year 1572,-an application of the nebular bypothesis; Wilcocks.

W. 8.

PROCEEDINGS BOSTON SOC. NAT. HIST., 1860.-p. 226, On two Birds from Bogota -Turdus minimus (Lafresnaye) and Vireo Bogotensis (Bryant); Dr. Henry Bryant. -p. 227, Fossiliferous slate and sandstone (Devonian) from the Dennis river, Maine; Prof. W. B. Rogers.-p. 228, Spines of Siluroid fishes from a whale's blubber; Capt. Atwood.-p. 229, "Cocoa-nut pearl;" Dr. C. F. Winslow.-p. 229, Discussion on the subject of Vision; Dr. J. B. Jeffries, Prof. W. B. Rogers, and Dr. Gould-p. 231, Discussion on the theory of Darwin; Agassiz, Emerson, and Prof. W. B. Rogers.— p. 235, Description of Hoplocampa rubi, by the late Dr. T. W. Harris; with remarks on its history by Noyes Darling, Esq.; Mr. Scudder.—p. 236, Geological map of Vermont; Mr. C. H. Hitchcock, with remarks by Prof. W. B. Rogers.-p. 239, Section of an elephant's tooth as an example of Osteo-dentine; Dr. White.-p. 240, Laws of fracture of a thick glass tube; Prof. W. B. Rogers.

THE

AMERICAN

JOURNAL OF SCIENCE AND ARTS.

[SECOND SERIES.]

ART. XV.-On the Nebular Hypothesis; by Professor DANIEL KIRKWOOD, Bloomington, Indiana.

THE records of our planet's physical history, from the dawn. of organized existence down to the epoch of man's creation, have, for the most part, been brought to light since the commencement of the nineteenth century. Within this brief period the immense antiquity of our globe, the former high temperature of its surface, and, in short, all the main facts and doctrines of geology, have been discovered or confirmed by a laborious examination of the planetary crust. But the earth has also a pregeologic history-a history as yet undeveloped; the grand outlines of which must be derived chiefly from celestial phenomena. "The testimony of the rocks" in regard to the one, may be more explicit than that of the stars in regard to the other. It must be borne in mind, however, that this department of researchthe tracing of astronomical facts not accounted for by gravitation, to their source in the origin of the system-has hitherto received but little attention from men of science. Cogent arguments, it is true, were adduced by Laplace and Pontécoulant in favor of the nebular hypothesis, but very little has since been accomplished, tending either to invalidate or confirm it.

The present article is designed as a popular rather than a scientific discussion of this interesting subject, and we trust its interest will not be abated by the fact that a portion of the matter has been before presented by us anonymously in a Quarterly Review. We shall in the first place present a brief account of the origin and nature of Laplace's theory; secondly, a connected

AM. JOUR. SCL-SECOND SERIES, VOL. XXX, No. 89.-SEPT., 1860.