subject. A brief review of the author's facts and conclusions have been given in volume xlv (p. 358) of this Journal, in a letter from the author. The many plates contain various contour maps, and views of reef regions, of aeolian bluffs and rock, and illustrations of other subjects. Plate VIII is a colored contour map of the Caribbean Sea.

Prof. Agassiz, in discussing the origin of coral reef limestones, states objections to the subsidence theory of Darwin. Without touching here on the special arguments in its favor, two or three general facts may be stated.

In geological history, many limestones have been made exceeding 1000 feet in thickness which show by their fossils that they are not of deep water origin. Whether derived from coral and shell sediment like coral reef rock, or from shell sediment chiefly makes no difference; subsidence was required.

Subsidences of one or two scores of thousands of feet in depth have taken place in past time, over the region of the Appalachians, Alps, and other mountain regions; and in the sinking trough, sediments were formed successively at the water's level, or not far below it, to the thickness of the depth of subsidence; and some of the sediments were calcareous, making now thick limestone strata.

After the Cretaceous period, and in the Pliocene Tertiary chiefly, or the Tertiary and Glacial period, the whole region of the Rocky Mountains was elevated; the elevation was 16,000 feet in part of Colorado, 10,000 feet at least in the region of the Sierra Nevada, 10,000 feet in Mexico, and over 17,000 feet in British America, latitude, 49° to 53° and less to the north. The region of the Andes, at the same time, was raised to a maximum amount of 20,000 feet; the Alps, 12,000; the Himalayas, 20,000 feet. Moreover, at the close of the Champlain period there was another epoch of smaller elevation, introducing the Recent period. These elevations, affecting a large part of the continental areas, could not have taken place without a counterpart subsidence of large areas over the oceanic basin; profound oceanic subsidence was hence in progress during the growth of coral reefs. The subsidence cannot be questioned.

J. D. D.

2. Formation of Dolomite.-C. KLEMENT, has a paper on the formation of dolomite in the "Bulletin de la Société Belge de Géologie, Paléontologie et Hydrologie," Volume viii, Brussels. 1894. In experiments, proceeding on the ground that the calcium carbonate of corals is in the state of aragonite, he digested in a covered platinum capsule, at a temperature of 90° to 92° C., finely pulverized aragonite, with a concentrated solution of common salt and magnesium chloride and sulphate in the proportions occurring in sea-water.

In his several trials he obtained a compound containing, besides lime and carbonic acid, 15 to 32.5 per cent. of magnesia, corresponding to 315 to 68.3 per cent. of magnesium carbonate. During the operation, the solution employed was gradually con

centrated even to an abundant deposition of common salt. On account of the minuteness of the crystals, he was not able positively to prove their rhombohedral character, but believes that there is little doubt of this. The author deduces from his experiments, that the massive dolomite limestones have been produced in closed lagoons along a sea bottom through the action of the sea-water, concentrated by the sun's heat, on coralmade sediments, conforming, as he says, to Dana's views on Dolomization.

It should be here understood that Dana has never supposed that the dolomized calcareous sediments were always, or generally, those of coral reef origin; but that any calcareous sediments, whether from shells or corals, or any other source, would undergo the chemical change, under the conditions stated. It is important, therefore, to note that the shells of most Gastropods and Cephalopods, and the inner pearly layer of many Lamellibranchs, are aragonite; and that such shells contribute to the material of coral reef rocks, as well as to ordinary lime

stones.

J. D. D.

3. On Dolomite-making and dolomitic calcareous organisms.Under this title, A. G. HÖGBOM, of Stockholm, discusses (Jahrb. f. Min., Geol. und Pal., 1894, vol. i, p. 272), the question as to the origin of the magnesia of dolomitic limestones. He finds by analysis that the common incrusting Nullipores of coral reefs-species of the genus Lithothamnion-commonly contain a large percentage of magnesium carbonate. He gives the results of fourteen analyses-1 by himself, 9 by N. Sahlbom, 3 by R. Mauzelius, and 1 by J. Guinchard, and he deduces for the mean of the whole, 10 parts of magnesium carbonate to 100 of calcium carbonate.

Mr. Högbom also cites results from analysis of Bermuda corals, by G. Forsstrand, in which the amount of magnesium carbonate and calcium carbonate, was, for a Porites, 062 and 95 94; for an Oculina, 0.36 and 96-20; for Millepora alcicornis, 0.41 and 95.86; for another Millepora, 0.77 and 94-39; for the reef rock of the Bermudas, 164 and 95'43; for 10 species of shells of Gastropods and Lamellibranchs from the outer edge of the reef, 0.19 and 97.32; but for a fine mud of terra cotta color from the lagoon, 4:04 and 92.93.

The author concludes that the magnesia of dolomite has probably come from an organic source; and that consequently the hypothesis of Dana, which derives it from the sea-water of evaporating basins, appears to be unnecessary.

We add here some additional facts.

Damour, in 1850, published an analysis (Bull. G. S. de France, vii, 675) of a specimen from Bréhat, on the coast of northwestern France, which he called a Millepora (M. cervicornis), but also said it was one of the Algos, and of concretion-like form. It afforded him 8.51 per cent of magnesium carbonate and 87.32 of calcium carbonate,

The common Millepora alcicornis, of the West Indies, afforded S. P. Sharples 97.46 p. c. of calcium carbonate with 0.27 of calcium phosphate and 2.54 of water and organic matters. (This Journal, III, i, 168, 1871). In his analyses of Oculina arbuscula, Manicina areolata, Siderastrea radians, Madrepora cervicornis, and M. palmata, he obtained no magnesia but in each some calcium phosphate. It is to be noted that other analysts have overlooked apparently the calcium phosphate.

Forchhammer, analyzing a mixture of corals, found about half a per cent of magnesium carbonate; but in the Alcyonarian, Isis nobilis 6:36 per cent, and Corallium nobile 2.1 per cent.

4. Bahama Expedition of the State University of Iowa. Narrative and Preliminary Report; by Professor C. C. NUTTING. 252 pp. 8vo, No. 1 and 2 of Vol. III of the Natural History Bulletin of the University.

This volume is an account of a cruise to the Bahama Banks and the islands in their vicinity, by the members of a class in Natural History of the Iowa University, with Professors Nutting, G. L. Houser and H. F. Wickham as the executive committee, in all a party of twenty-one. It proved to be eminently satisfactory, both personally and as regards accessions to the University

collections.

The Report contains brief notes on some of the species dredged or otherwise collected, with several figures in illustration; but the final descriptions are to appear later, specimens having been placed in the hands of different specialists. The volume has great value to any who may plan such expeditions on account of the descriptions of its outfit, the information to be gathered from the experiences of the cruise, and many facts observed along the way.

III.

J. D. D.

MISCELLANEOUS SCIENTIFIC INTELLIGENCE.

1. National Academy of Sciences.-At the annual meeting held at Washington, April 16-19, Dr. Wolcott Gibbs, one of the original charter members of the Academy, was elected president for a term of six years, Professor Marsh, president for the last two terms, having declined to be a candidate. The Academy voted unanimously "That the thanks of the Academy be tendered to the retiring president for the zeal and ability with which he has administered, in succession, the offices of Vice-president and President of the Academy during a period of seventeen years." Prof. Alexander Agassiz was elected foreign secretary, and Prof. Asaph Hall, reëlected home secretary.

Three foreign associates, Professor R. Leuckart of Leipzig, Professor Julius Sachs of Würzburg, and Professor Sophus Lie of Leipzig, were elected; also four new members.

The Barnard gold medal was awarded by the Academy to Lord Rayleigh for the discovery of argon, and the Watson gold medal to Seth C. Chandler for his researches on the variation of latitude, on variable stars and for his other works in astronomy.

The president announced the death of Professor James D. Dana, one of the original members of the Academy, and appointed Dr. E. S. Dana to prepare the biographical memoir. The president also appointed a special committee to represent the Academy at the funeral.

The following papers were read:

A. AGASSIZ and W. McM. WOODWORTH: On some variations in the genus Eucope.

A. AGASSIZ: Notes on the Florida Reef. The progress of the publications on the expedition of 1891 of the U. S. Fish Commission Steamer "Albatross," Lieut. Commander Z. L. Tanner, commanding.

M. P. RAVENEL: On soil bacteria.

A. M. MAYER: A linkage showing the laws of the refraction of light.

M. CAREY LEA: On the color relations of atoms, ions and molecules.

R. S. WOODWARD: Mechanical interpretation of the variations of latitude.

S. C. CHANDLER: On a new determination of the nutation-constant, and some allied topics.

L. A. BAUER: On the secular motion of a free magnetic needle.

J. S. BILLINGS: On the composition of expired air, and its effect upon animal life.

TH. GILL: Systematic catalogue of European fishes.

E. D. COPE: The extinct Cetacea of North America.

G. BROWN GOODE: On the application of a percentage method in the study of the distribution of oceanic fishes; (A.) Definition of eleven faunas and two subfaunas of Deep Sea fishes; (B.) The relationships and origin of the CarribeoMexican and Mediterranean sub-faunas.

IRA REMSEN: On the two isomeric chlorides of ortho-sulpho-benzoic acid. On some compounds containing two halogen atoms in combination with nitrogen. B. A. GOULD: Biographical memoir of Dr. Lewis M. Rutherfurd.

H. A. NEWTON: Relation of Jupiter's orbit to the mean plane of four hundred and one minor planet orbits. Orbit of Miss Mitchell's comet, 1847 VI.

2. Penck's Morphologie der Erdoberflache.*-Professor PENCK has added in his Morphologie der Erdoberfläche another notable number to Ratzel's series of geographical handbooks. The numbers already issued include Ratzel's Anthropogeographie, Hann's Klimatologie, Boguslawski and Krümmel's Ozeanographie, and Heim's Gletscherkunde; all standard works on their respective subjects. Penck's contribution is fully up to the high quality of its predecessors.

The plan of the present work may be fairly inferred from an abstract of its table of contents, as follows:-The form and size of the earth; area of land and water, mean altitude of lands and depth of seas, volume of lands and seas; continents and oceans and their permanence. Land surfaces; weathering and denudation by wind, rivers, and ice; deformations of the surface. The forms of the surface; plains, hills of accumulation, valleys, basins, mountains, depressions, caverns. The sea; its movements, coasts, and botton; islands.

Under most of these subjects, the processes of form production, and the forms thus produced are separately considered; the general accounts of denudation found in geological treatises not

*Morphologie dor Erdoberfläche von Dr. Albrecht Penck, Professor der Geographie an der Universität Wien. Stuttgart, Engelhorn, 1894. 2 vols. 8vo. 471 and 696 pp. Author and subject indexes.

serving the author's purpose in his special treatment of the land. Much of the book is therefore Morphogenie, rather than Morphologie. Throughout both volumes, the citations of geological and geographical literature are remarkably numerous, and must serve an excellent purpose to those who wish to carry their studies to original sources.

W. M. D.

3. Orbit of Miss Mitchell's Comet, 1847, VI; by H. A. NEWTON. -The computation of a definitive orbit for the Comet 1847, VI, is the subject of a memoir by Miss Margarita Palmer, being her thesis presented for the degree of Doctor of Philosophy conferred on her in 1894 by Yale University. Her work is published in the Transactions of the Yale Observatory. She found that a hyperbolic orbit better satisfied all the observations than did a parabola, though the best parabolic orbit does not do great violence to the observations. The best hyperbola has an eccentricity of 1.0001727. A cursory examination shows that the position of Jupiter for a few years before 1847 was such as to increase the eccentricity of the comet's orbit. Herr THRAEN has shown (Astronomische Nachrischten, No. 3249), that the action of Jupiter and other planets upon the Comet 1886, II, previous to its period of visibility was enough to explain a change from a parabolic orbit to the hyperbola demanded for that comet by the observations. It seemed worth while to compute the like perturbations for the Comet 1847, VI.

I find that from June, 1843, to November, 1847, the action of Jupiter and Saturn combined increased the eccentricity by 000151. The action of Saturn was about one-thirtieth that of Jupiter. Previous to June, 1843, the action of Jupiter was to diminish the eccentricity of the orbit. Thus between February, 1838, and June, 1843, it changed the eccentricity by 000034. During the whole period of ten years the change, therefore, was 000117.

This explains so large a part of the computed excess of eccen tricity over unity that it is fair to assume that a parabola to which these perturbations shall be applied would represent satisfactorily all the observations of the Comet 1847, VI.

OBITUARY.

DR. GIDEON E. MOORE of New York City died on April 13th at the age of fifty-three. He was a well known chemist, who had made some valuable contributions to the science, particularly in the line of mineral analysis.

PROF. JAMES E. OLIVER, the distinguished mathematician, who had been connected with Cornell University since 1871, died March 27. He was the author of a number of standard mathematical works.

FRANCESCO SANSONI, Professor of Mineralogy at the University of Pavia and author of many scientific papers, died about a month since.

It is announced in a recent number of "Nature that the reported death of PROFESSOR II. WILD of St. Petersburg (see p. 328 of this volume), was happily a mistake, due to a confounding of similar names.