Scientific Serials

Abstract

American Journal of Science, April.—On allotropic silver, by M. Carey Lea. This paper is in continuation of one contained in the March number of the Journal, in which the gold-coloured forms of allotropic silver were examined. The subject now considered is the relation existing between the allotropic forms of silver taken generally and silver as it exists in its compounds, and more especially in the silver haloids. The investigation leads to the conclusion that silver may exist in three forms:— (i) Allotropic silver, which is protean in its nature, may be soluble or insoluble in water, and have almost any colour; but in all its insoluble varieties always exhibits plasticity. It is chemically active. (2) The intermediate form, which may be yellow or green, but is never plastic, and is almost as indifferent chemically as white silver. (3) Ordinary silver. Allotropic silver is affected by all forms of energy, and the effects are strikingly analogous to those produced on silver haloids by the same agencies. It is, therefore, concluded that in the silver haloids silver may exist in the allotropic form.—The phenomena of rifting in granite, by Ralph S. Tarr.—The red-rock sandstone of Marion County, Iowa, by Charles R. Keyes.—The volumetric composition QI water, by Edward W. Morley (continued from the March number of the Journal). The hydrogen used in the investigation was obtained by the electrolysis of dilute sulphuric acid. By this means it has been found possible to get hydrogen containing less than one-hundreth of a cubic centimetre of nitrogen in two litres of hydrogen, and containing no other impurity in amount large enough to be detected. An apparatus for the measurement of gases has been constructed, in which the mean error of measurement of the volume of hydrogen and oxygen used in the experiments has been less than one part in fifty thousand. With this, twenty experiments have been made, which give a maximum value for the composition of water 2˙00047, a minimum value of 2˙00005, and a mean value 2˙00023.. The composition of water may, therefore, be taken as 2˙0002 volumes of hydrogen to one volume of oxygen.—On certain points in the estimation of barium as the sulphate, by F. W. Mar. Some experiments made by the author indicate that hydrochloric acid may be introduced freely and without detriment to quantitative exactness, in the precipitation of barium in the form of sulphate from pure solutions. Up to a determined point, the amount of hydrochloric acid employed accelerates the precipitation. The quantity of alkaline salts present is shown to have no very marked influence on the time of formation of the precipitate.— On halotrichite, or feather alum, from Pitkin County, Colorado, by E. H. S. Bailey. An analysis of the mineral shows that it is essentially a sulphate of alumina and ferrous oxide, with a part of the former replaced by ferric oxide, and a part of the ferrous oxide replaced by magnesia.—On a new serpent from Iowa, by R. Ellsworth Call.—On crystallized azurite from Arizona, by O. C. Farrington.—On the occurrence of xenotime as an accessory element in rocks, by Orville A. Derby.—On the magnetite ore districts of Jacupiranga and Ipanema, Sao Paulo, Brazil, by Orville A. Derby.—On pink grossularite from Mexico, by C. F. de Landero.—Restoration of Triceratofs, by O. C. Marsh.—Development of the Brachiopods, Part I, introduction, by Dr. Charles E. Beecher.