7o6 



THE POPULAR SCIENCE MONTHLY 



cies in the course of a few miles' flow. They 

 see no objection to discharge into tide-waters 

 or large lakes, and meet the argument as to 

 waste of material by stating that the organic 

 matter in sewage serves as food for low forms 

 of animal life, which in turn sustain food 

 fishes. The various modes of treating sew- 

 age by chemical precipitation, broad irri- 

 gation, and intermittent filtration are then 

 described. Since rye grass, one of the spe- 

 cies of useful plants that succeed best on 

 sewage farms, does not cure easily, but may 

 be readily preserved by ensilage, the silo 

 beomes a valuable adjunct to the sewage 

 works. In the portion of the volume de- 

 voted to descriptions of works, the establish- 

 ments at more than twenty places are de- 

 scribed with considerable detail and with 

 figures, maps, and diagrams. There are also 

 brief accounts of the use of sewage for ir- 

 rigation at a number of places in the West. 

 Various laws and codes of rules regulating 

 the disposal of sewage in the United States 

 and England are given in appendixes. 



A Handbook of Gold Milling. By Henry 



Louis. London and New York : Mac- 

 millan & Co. Pp. 504. Price, $3.25. 



But few arts remain that have not been 

 brought under the sway of science, with the 

 result of securing improved products, a re- 

 duction of waste, lessened drudgery for 

 man and beast, or an increased return for 

 the same amount of effort. The separation 

 of gold from the rock and gravel in which it 

 occurs was carried on by wasteful empiric 

 methods so long as rich deposits were avail- 

 able, but now that lower-grade ores must be 

 largely depended upon, a disposition to 

 work in the light of exact knowledge is be- 

 coming manifest. The present volume is 

 designed to aid in the technical instruction 

 of gold millers. It gives no space to the 

 separating operations connected with hy- 

 draulic mining, the stamp mill being its only 

 theme. After some preliminary chapters on 

 the occurrence of gold, the properties of 

 gold and mercury, and the formation of 

 amalgams, the processes and appliances for 

 the several steps of the modern milling pro- 

 cess are taken up in order. Rock breakers, 

 mortar boxes, stamps, frames, guides, and 

 their various accessories are described and 

 are illustrated in views and detailed draw- 



ings. The processes of amalgamation, con- 

 centration, cleaning-up, and the cleaning, 

 retorting, and melting of the amalgam are 

 then discussed and the appliances required 

 for them are set forth. Some information is 

 given with regard to the cost of milling, 

 labor, power, sampling, and assaying of ore, 

 etc., and several useful tables together with 

 an essay on the cam curve are contained in 

 an appendix. 



The Industries of Russia. Prepared by 

 the Department of Trade and Manufac- 

 tures, Ministry of Finance, for the World's 

 Columbian Exposition. Editor of the 

 English translation, John Martin Craw- 

 ford, U. S. Consul General to Russia. 

 G. P. Putnam's Sons, New York, Ameri- 

 can Agents. Five volumes. Price, $6. 



The Russian Empire took an active part 

 in the exhibition of 1893 at Chicago. Wish- 

 ing to afford the American people a fuller 

 idea of the industrial capabilities of Russia 

 than the material exhibit of that country 

 could convey, the Imperial Minister of Fi- 

 nance caused to be prepared this series of 

 volumes which comprise sketches, by espe- 

 cially qualified writers, of the several chief 

 industries of the empire. The first volume 

 is devoted to manufactures and trade, and 

 opens with a general view of this field by 

 the distinguished chemist, Prof. D. 1. Men- 

 deleeff, who also contributes papers on the 

 chemical industry and naphtha to this vol- 

 ume. Papers on the various textiles are 

 furnished by N. P. Langovoy, professor in 

 the St. Petersburg Technological Institute, 

 and others on paper, leather, metals, glass, 

 food products, tobacco, spirits, shipbuilding, 

 etc., are contributed by other writers. Of a 

 more general scope are the essaj's on the in- 

 terior trade and fairs of Russia, the for- 

 eign trade, wages and working hours in 

 factories, tariff systems, etc. The third vol- 

 ume, which is the largest of the five, con- 

 taining over five hundred pages, is devoted 

 to agriculture and forestry, the various 

 features of these industries being treated by 

 a large number of sjjecial writers. Mining 

 and metallurgy are treated in a volume of a 

 hundred pages by Mr. A. Keppen, mining 

 engineer. The fifth volume is devoted to 

 Siberia and the Great Siberian Railway, giv- 

 ing a description of the country and its re- 

 sources, the history of its occupation by 



