SCIENTIFIC PUBLICATIONS. 31 



O'CONNOR, HENRY. The Gas Engineer's Pocket 

 Book. Comprising Tables, Notes and Memoranda ; relating to the 

 Manufacture, Distribution and Use of Coal Gas and the Construc- 

 tion of Gas Works. Second edition, revised. 12mo, full leather, gilt 

 edges $3.50 



OLSEN, Prof. J. C. Quantitative Chemical Analysis. 



In Press. 



OSBORN, FRANK C. Tables of Moments of Inertia, 



and Squares of Radii of Gyration; Supplemented by others on the 

 Ultimate and Safe Strength of Wrought Iron Columns, Safe Strength 

 of Timber Beams, and Constants for readily obtaining the Shearing 

 Stresses, Reactions, and Bending Moments in Swing Bridges. 12mo, 

 leather $3.00 



OSTERBERG, MAX. Synopsis of Current Electrical 



Literature, compiled from Technical Journals aiid Magazines during 

 1895. 8vo, cloth $1.00 



OUDIN, Maurice A. Standard Polyphase Apparatus 



and Systems. With many diagrams and figures. Third edition, 

 thoroughly revised. Fully 1 1 lust rated $3.00 



PALAZ, A., ScD. A Treatise on Industrial Photome- 

 try, with special application to Electric Lighting. Authorized trans- 

 lation from the French by George W. Patterson, Jr. Second edition, 

 revised. 8vo, cloth. Illustrated. $4.00 



PARR, G. D. A. Electrical Engineering Measuring 



Instruments, for Commercial and Laboratory Purposes. With 370 

 diagrams and engravings. 8vo, cl., illustrated. 328 pp > t, $3.50 



PARRY, ERNEST J., B. Sc. The Chemistry of Essen- 

 tial Oils and Artificial Perfumes. Being an attempt to group together 

 the more important of the published facts connected with the subject; 

 also giving an outline of the principles involved in the preparation and 

 analysis of Essential Oils. With numerous diagrams and tables. 

 8vo, cloth, illustrated net. $5.00 



PARRY, LEONARD A., M. D. The Risks and Dan- 

 ger* of Various Occupations and their I'n-vcntion. A book that 

 should be in the hands of manufacturer*, tin- uiolical profession, 

 sanitary inspectors, medical officers of health, managers of works, 

 foremen and workmen. 8vo, cloth nil. $3.00 



PARRY, E. J. and J. H. COSTE. Chemistry of Pig- 



mentH. \\ithtablesandfigures. 8vo, cl., illim., '2*0 pages. nr<. $4.50 



PARSHAXL, H. F., and HOB ART, H. M. Armature 



Windings of Electric Machines. With 140 full page plates, 65 ta- 

 bles, and 165 pages of descriptive letter-press. 4to, cloth $7.50 



