propylene (propilen)

[ IMG:content-1120.jpg:[blocks in formation] considered by him as characteristic of various important silver-mining regions, especially those of Washoe (in Nevada) and Hungary. It is a considerably altered form of andesite, or of some igneous rock more or le nearly related to it. The metamorphism which was displayed in the formation of the metalliferous deposits of these regions was also attended by great changes in the inclosing and a ociated rocks. Also called greenstone trachyte. I hope shortly to be able to describe some of the chief types of these rocks, their altered forms (the propy lites ), and their Plutonic representatives (diorites and quartz-diorites). propyl i tic (prop-i-lit'ik), a. [ Quart. Jour. Geol. Soc., XLV. 201. IMG:content-1121.jpg:[ocr errors] Propylon at Karnak, Egypt. towers in outline like truncated pyramids, of which one or a series stood before the actual entrance or pylon of most temples or other important buildings. At E abua, Girsheh, and Dandour, the cells of the temple have been excavated from the rock, but their courts and propylons are structural buildings added in front. J. Fergu on, Hist. Arch., I. 126. prora (pro'rä), n.; pl. proræ (-re). [NL., proral (prō'ral), a. [ pro rata (prō rā'tä). [ML.: L. pro, for, in accordance with; ML. rata, abl. sing. of rata, rate: see rate2.] In proportion. pro-ratable (pro-ra'ta-bl), l. [ II. in trans. To make arrangement or agreement on a basis of proportional distribution. A general circular was i ued from the Santa Fe headquarters yesterday giving notice to all lines doing busine between the Mi ouri River and St. Louis that it will hereafter refuse to prorate with them on shipments of grain and live stock. New York Tribune, June 6, 1890.