Produced by Olaf Voss, Don Kretz, Juliet Sutherland, Charles Franks and the Online Distributed Proofreading Team. [Illustration] SCIENTIFIC AMERICAN SUPPLEMENT NO. 286 NEW YORK, JUNE 25, 1881 Scientific American Supplement. Vol. XI, No. 286. Scientific American established 1845 Scientific American Supplement, $5 a year. Scientific American and Supplement, $7 a year. * * * * * TABLE OF CONTENTS. I. ENGINEERING AND MECHANICS.--One Thousand Horse Power Corliss Engine. 5 figures, to scale, illustrating the construction of the new one thousand horse power Corliss engine, by Hitch, Hargreaves & Co. Opening of the New Workshop of the Stevens Institute of Technology. Speech of Prof. R.W. Raymond, speech of Mr. Horatio Allen. Light Steam Engine for Aeronautical Purposes. Constructed for Capt. Mojoisky, of the Russian Navy. Complete Prevention of Incrustation in Boilers. Arrangement for purifying boiler water with lime and carbonate of soda.--The purification of the water.--Examination of the purified water.--Results of water purification. Eddystone Lighthouse. Progress of the work. Rolling Mill for Making Corrugated Iron. 1 figure. The new mill of Schultz, Knaudt & Co., of Essen, Germany. Railway Turntable in the Time of Louis XIV. 1 figure. Pleasure car. Railway and turntable at Mary-le-Roy Chateau, France, in 1714. New Signal Wire Compensator. Communication from A. Lyle, describing compensators in use on the Nizam State Railway, East India. Tangye's Hydraulic Hoist. 2 figures. Power Loom for Delicate Fabrics. 1 figure. How Veneering is Made. II. TECHNOLOGY AND CHEMISTRY.--The Constituent Parts of Leather. The composition of different leathers exhibited at the Paris Exhibition.--Amount of leather produced by different tonnages of 100 pounds of hides.--Percentage of tannin absorbed under different methods of tanning.--Amounts of gelatine and tannin in leather of different tonnages, etc. Progress in American Pottery. Photographic Notes.--Mr. Waruerke's New Discovery.--Method of converting negatives directly into positives.--Experiments of Capt. Bing on the sensitiveness of coal oil--Bitumen plates.--Method of topographic engraving. By Commandant DE LA NOE.--Succinate of Iron Developer.--Method of making friable hydro-cellulose. Photo-Tracings in Black and Color. Dyeing Reds with Artificial Alizarin. By M. MAURICE PRUD'HOMME. III. ELECTRICITY, PHYSICAL SCIENCE, ETC.--On Faure's Secondary Battery. Physical Science in Our Common Schools.--An exceptionally strong argument for the teaching of physical science by the experimental method in elementary schools, with an outline of the method and the results of such teaching. On the Law of Avogadro and Ampere. By E. VOGEL.