SCIENC 



New Series. 

 VOL. XI. No 274. 



Friday, March 30, 1900. 



Single Copies, 15 CTS. 

 Annual SnBSCKipxiON, $6.00 



John Wiley & Sons' 



SCIENTIFIC PUBLICATIONS 



Introduction to Ghemical Preparation. 



A Guide in the Practical Teaching of Inorganic Chemistry. 

 By Prof. Dr. Erdmann, of Halle. Authorized Translation 

 from the Second German Edition, by Frederick L. Dunlap, 

 S.D., Instructor in Industrial Chemistry at the Worcester 

 Polytechnic Institute. Fp. 12mo, cloth, $L.25. At Once. 



Dynamometers and the 



Measurement of Power. 



A Treatise on the Construction and Application of Dyna- 

 mometers. With a description of the methods and apparatus 

 employed in measuring water and electric-power. A'ew 

 edition, revised, with the addition of five new chapters and 

 the rewriting of some of the old ones. By J. J. Flather, 

 Professor of Mechanical Engineering in University of 

 Minnesota, Minneapolis, Minn, ix -|- 394 pages. 12mo, cloth, 

 gS.OO. 113 figures, including half-tones. 



The Theory and Practice of Surveying, 



Designed for the use of Surveyors and Engineers generally, 

 but especially for the use of vStudents in Engineering. By 

 J. B. Johnson. C.E., Dean of the Colleee of Mechanics and 

 Engineering of the University of Wisconsin. About 900 pp. 

 6 folding plates. Complete iades. 8vo, cloth, $4.00. 



Manual of Irrigation Engineering. 



By Herbert M. Wilson, C.E. Third edition. 560 pp. 39 

 plates. 124 figures. 8vo, cloth, $4.00. 



The Mechanical Engineer's 



Pocket Book. 



The Galorific Power of Fuels ; 



With a colleciion of auxiliary tables and tables showing the 

 heat of combustion of fuels, solid, liquid, and gaseous; to 

 which is also appended the Report of the Committee on 

 Boiler Tests of the American Society of Mechanical Engi- 

 neers. (December, 1899.) By Herman Poole. Second edi- 

 tion, revised and enlarged. 279 pp. 40 figures. 8vo, 

 cloth, ^3.00. 



Topographic Surveying ; 



Including Geographic, Exploratory, and Military Mapping ; 

 with Hints on Camping, Emergency Surgery, and Photo- 

 graphy. By Herbert M. WiLson, C.E., Geographer, U. S. 

 Geological Survey. Author of "A Manual of Irrigation 

 Engineering." Over 900 pp. 8vo, cloth. Shortly. 



Railroad gonstruction ; 



Theory and Practice. 



A text book for the use of students in colleges and technical 

 .schools By Walter L. Webb, Associate Professor of rjivil 

 Engineering in the University of Pennsylvania. 466 pp. 

 8vo, cloth. Shortly. 



JOHN WILEY & SONS, 43 and 45 East 19th St, New York City. 



i»&#&S#&#©®##©##©^#»©#*##&#9»©###&^#a##^#^###»^#^©&99©#&#.»##9©#a^8g 



is used in all MODERN 

 . ELECTRICAL LAB- 



^'Willyoung Apparatus* 



ORATORIES, in most of the GOVERNMENT DEPARTMENTS, 

 on U. S. WAR SHIPS, and wherever ACCURACY AND RELI- 

 ABILITY is understood 



filiyoung 8" to I5"-110 Voll X Ray Mach 



Willyoune X-Ray Machines -"^p'""^"^ ^"<i ^^,^ 



i 2 i always set the pace in 



this line. Adopted by the U. S. MARINE HOSPITAL SERVICE. 

 We make a fuH line of GALVANOMETERS, SHUNTS, RESIS- 

 TANCE BOXES, WHEATSTONE'S BRIDGES, ELECTROM- 

 ETERS, OSCILLOGRAPHS, ETC 



Special ^tes to Colleges, Wriie to us. 



1 ELMER G. WILLYOUNG {lZ^tlJJ^°::^t)f 82-84 Fulton St., New York 



