Scientific Serials

    Abstract

    American Journal of Science, March.—On gold-coloured allotropic silver, by Mr. M. Carey Lea. The present paper is in continuation of one published in this Journal in June 1889, and has for its object the description of the reactions of gold-coloured allotropic silver. It is shown that there exists a well characterized form of silver, intermediate between the allotropic silver previously described and ordinary silver, differing in a marked manner from both. All forms of energy act upon allotropic silver, converting it either into ordinary silver or into the intermediate form. Mechanical force (shearing stress) and high tension electricity convert it directly into ordinary silver. Heat and chemical action convert it first into the intermediate form, then into ordinary silver. The action of light is to produce the intermediate form only, and even the most prolonged action at ordinary temperatures does not carry it beyond this. A remarkable parallelism appears to exist between the action of these forms of force on allotropic silver and their action on the silver haloids, indicating that it is not improbable that in these haloids silver may exist in the allotropic condition. Three coloured plates accompanying the paper illustrate the changes described.—The flora of the Great Falls coal-field, Montana, by J. S. Newberry.—High-level shores in the region of the Great Lakes, and their deformation, by J. W. Spencer.—On the composition of pollucite and its occurrence at Hebron, Maine, by G. H. L. Wells.—The volumetric composition of water, by Edward W. Morley. A description is given of the apparatus used to obtain results which will be published in the next number.—On the intensity of sound: a reply to a critic, by Charles K. Wead.—The fire-ball in Raphael's “Madonna di Foligno,” by Prof. H. A. Newton. The fire-ball painted by Raphael in his picture, the “Madonna di Foligno,” is most probably representative of one that fell at Crema in September 1511. Some political events of importance to Italy and the Pope, which transpired in 1512, were supposed to be connected with the fall of stones that occurred. It appears natural, therefore, that Raphael should introduce the Crema fire-ball into the altar-piece he was painting at the time.

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    Scientific Serials. Nature 43, 500–501 (1891) doi:10.1038/043500b0

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