Page:Popular Science Monthly Volume 48.djvu/311

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Progress of the World. Monthly, Vol. I, No. 1, October, 1895. New York: Progress of the World Company, 156 Fifth Avenue. Pp. 156. 10 cents; $1 a year.

Richards, Frank. Compressed Air. New York: John Wiley & Sons. London: Chapman & Hall. Pp. 203.

Risteen, A. D. Molecules and the Molecular Theory of Matter. Boston and London: Ginn & Co. Pp. 233. $2.

Romanes, George John. Darwin and after Darwin. II. Post-Darwinian Questions; Heredity and Utility. Chicago: Open Court Publishing Company. Pp. 344. $1.50.

Salazar, A. E., and Newman. Q. Estudios Ijiéniquos del Aire (Hygienical Studies of the Air). Santiago, Chile. Pp. 20, with Plates.

Scott, E. G. Reconstruction during the Civil War in the United States of America. Boston and New York: Houghton, Mifflin & Co. Pp. 483. $3.

Sizer, Nelson. How to Study Strangers, by Temperament, Face, and Head. New York: Fowler & Wells Company. Pp. 367. $1.50.

Smithsonian Institution. An Account of its Origin, History, Objects, and Achievements. Pp. about 20, with Plates.—The Exhibit of the Institution at the Cotton States Exposition, Atlanta, 1895. Pp. about 80.

Stevens, W. Le Conte. Recent Progress in Optics. Salem, Mass.: The Salem Press. Pp. 22.

Stoddard, Charles Augustus. Cruising among the Caribbees . New York: Charles Scribner's Sons. Pp. 198. $1.50.

Stuver, E. Asexualization for the Limitation of Disease, and the Prevention and Punishment of Crime. Rawlins, Wyoming. Pp. 16.

United States Life-Saving Service, Annual Report of Operations, 1894. Washington: Government Printing Office. Pp. 470.

Whiteley, R. Lloyd. Organic Chemistry. The Fatty Compounds. New York and London: Longmans, Green & Co. Pp. 285.

Winterburn, Florence Hull. Nursery Ethics. New York: The Merriam Company. Pp. 341.

Wright, Carroll D., United States Commissioner of Labor, and Gould, E. R. L. The Housing of the Working People. (Eighth Special Report of the Commissioner of Labor.) Washington: Government Printing Office. Pp. 461.

Fragments of Science.

Constituents of Ocean Bottoms.—In his summary of the results of the Challenger Expedition, Dr. Murray classifies marine deposits as littoral, shallow water, and deep sea. Such deposits are, in origin, either land-derived or pelagic—that is, of the ocean. The land-derived deposits edge the shores, for the finest river mud is rarely met with as far as three hundred miles from the coast, and particles so large as to be called sand remain close to it. Regarded in this light, the whole ocean beyond the three-hundred-mile belt of "territorial waters" possesses a distinct individuality, invaded by no material of land origin except the mud and boulders carried by drifting ice, the dust which settles out of the air, and scraps of floating pumice from volcanic eruptions. In a few patches less than seventeen hundred fathoms deep, far from land, the remains of relatively large and delicate shells which lived on the surface abound at the bottom, mixed with innumerable shells of dense, nearly microscopic foraminifera and a little clayey matter, the whole receiving the general name of pteropod ooze, from the characteristic shells of pteropods which occur in it. In deeper waters no pteropod or other delicate shells are found, and the calcareous meal of foraminifera, closely resembling softened chalk, is called globigeiina ooze, from the particular genus of surface-living organism which occurs in largest proportion. At greater depths globigerina ooze is found in which the microscopic shells appear much corroded; and finally, in the deeps or areas more than three thousand fathoms below the surface, the deposit is almost free from carbonate of lime, and forms a stiff red clay composed of decomposed volcanic or atmospheric dust and those constituents of shells that are not readily dissolved by sea water. The process of formation has been clearly shown. Over the whole surface the same shell-bearing creatures die in myriads; their bodies fall continuously as a gentle calcareous snow shower through the water, which slowly dissolves them. The large thin shells vanish first, and only reach the bottom in shallow water; the dense spheres of the pinhead and smaller foraminifera resist longest, and only the insoluble residue reaches the greatest depth. Thus the excess of carbonate of lime dissolved in the deepest layers of the ocean is readily explained. The red clay forms so slowly that particles of metallic dust from exploded meteorites, which are covered up by the surface accumulations