American Journal of Science, August.—Origin of corai reefs and islands, by James D. Dana. The arguments recently raised by Dr. A. Geikie against Darwin's theory of subsidence as an explanation of the formation of atolls, or barrier reefs inclosing a lagoon, are discussed and shown to be largely based on misunderstandings of the facts. It is pointed out that locai elevations within the sinking area are not evidence against a general subsidence, such locai disturbances and faults being almost necessary concomitants of subsidence. The conclusions as to changes of level in the large Pacifie groups south of the equator agree mainly with Darwin's views, and the subsidence indicated, according to him, by atolls, is shown to be real, not an apparent sinking due to change of water-level.—On the meteorite of Tomatlán, Jalisco, Mexico, hy Charles Upham Shepard. The striking peculiarity of this stone, which fell in August 1879, is the prevalence everywhere of octahedral crystals of nickeliferous iron. The specifie gravity of the two fragments examined was 347—4.43.—On the widespread occurrence of allanite as an accessory constituent of many rocks, by Joseph P. Iddings and Whitman Cross. From its mode of occurrence and association the authors conclude that allanite must now be added to the group of primary, accessory rock constituents, similar to zircon, sphene, and apatite, though much rarer than any of these. In some regions it appears to be quite uniforrnly distributed through certain types of rock, such as the porphyrites and allied porphyries of the Ten Mile District, Colorado.—Crystals of analcite from the Phœnix Mine, Lake Superior Copper Region, by Samuel L. Penfield. These crystals, which occur thickly grouped together on calcite and native copper associated with tabular crystals of apophyllite, are of all sizes fsom minute particles up to one centimetre in diameter. The smal ones are simply tetragonal trisoctahedrons of the form (211), 2-2; the larger ones are of the same form, but with the planes differcntly arranged.—On a differential resistance-thermometer, hy T. C. Mendenhall. This instrument has heen devised and constructed for the study of certain problems connected with meteorology, especially the observation of soil and earth temperature, and the use of which would not demand greater skill than that of the ordinary meteorologicai ohserver. It consists essentially of a mercurial thermometer, not unlike ordinary forms, except that the bulb is greatly enlarged, so that the stem may have a diameter of about a millimetre, still leaving the scale tolerably open. By its means observations may he taken in less than a minute, no time being consumed in the preparation of liquids of known temperature at the observing station, as in the use of the thermo-junction on the resistance coil.—Impact friction and faulting, hy George F. Becker. The author discusses the phenomenon of “step faults”, as described in Mr. Geikie's “Text-Book of Geology,” p. 532, which he concludes to be not merely local, but of general occurrence.—A standard of light, by John Trowbridge. Objections are raised to the standard adopted at the Paris Conference of 1881—4 that is, the light emitted by a surface of platinum at the point of solidification. A more satisfactory standard might be an incandescent strip of platinum radiating a definite amount of energy, this energy being measured at a fixed distance, which will best agree numerically with the absolute system of measures now universally adopted in heat and electricity.—On hanksite, a new anhydrous sulphato-carbonate of sodium from San Bernardino county, California, by W. Earl Hidden. This new Californian mineral has a density of 2.562, hardness 3—3.5, and is readily soluble in water, yielding an abundant precipitate of barium sulphate when barium chloride is added to the solution. The author names it “hanksite”, after Prof. Henry G. Hanks, whose name is so intimately associated with the mineralogy of the Pacific coast.—Mineralogical notes, by Edward S. Dana and Samuel L. Penfield. The chief subjects of this paper are the analysis of a large crystal of hanksite from California and an artificial crystallised lead silicate from the Desloge Lead Company, St. Fran¸ois County, Missouri.—On the amount of moisture which sulphuric acid leaves in a gas, by Edward W. Morley.—Local deflections of the Drift Scratches in Maine, by G. H. Stone. Traces of these indications of secondary glaciation have been observed, especially in the Sebasticook Valley, the Belfast and St. George River districts.—Successional relations of the species in the French Old Tertiary, by Otto Meyer. In these, as well as in the corresponding American formations, many animal and vegetable species can be traced along through the succeeding strata, the latter being apparently connected by descent with the earlier forms. The paper is accompanied by a comparative table of Lower, Middle, and Upper Eocene and Oligocene forms illustrating this principle.
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Dec 1, 1949
James Kucyniak 
Open Access