Produced by Juliet Sutherland and the Online Distributed Proofreading Team at www.pgdp.net. [Illustration] SCIENTIFIC AMERICAN SUPPLEMENT NO. 441 NEW YORK, JUNE 14, 1884 Scientific American Supplement. Vol. XVII., No. 441. Scientific American established 1845 Scientific American Supplement, $5 a year. Scientific American and Supplement, $7 a year. * * * * * TABLE OF CONTENTS. I. CHEMISTRY AND METALLURGY.--On Electrolysis.--Precipitation of lead, thallium, silver, bismuth, manganese, etc.--By H. SCHUCHT The Electro-Chemical Equivalent of Silver Zircon.--How it can be rendered soluble.--By F. STOLBA A New Process for Making Wrought Iron Directly from the Ore. --Comparison with other processes.--With descriptions and engravings of the apparatus used Some Remarks on the Determination of Hardness in Water On the changes which Take Place in the Conversion of Hay into Ensilage.--By F.J. Lloyd II. ENGINEERING AND MECHANICS.--Faure's Machine for Decorticating Sugar Cane.--With full description and 13 figures The Generation of Steam and the Thermodynamic Problems Involved.--By WM. ANDERSON.--Apparatus used in the experimental determination of the heat of combustion and the laws which govern its development.--Ingredients of fuel.--Potential energy of fuel.--With 7 figures and several tables Planetary Wheel Trains.--Rotations of the wheels relatively to the train arm.--By Prof. C.W. MACCORD The Pantanemone.--A New Windwheel.--1 engraving Relvas's New Life Boat.--With engraving Experiments with Double Barreled Guns and Rifles. --Cause of the divergence of the charge.--4 figures Improved Ball Turning Machine.--1 figure Cooling Apparatus for Injection Water.--With engraving Corrugated Disk Pulleys.--1 engraving III. TECHNOLOGY.--A New Standard Light Dr. Feussner's New Polarizing Prism.--Points of difference between the old and new prisms.--By P.R. SLEEMAN Density and Pressure of Detonating Gas IV. ELECTRICITY, LIGHT, ETC.--Early History of the Telegraph. --Pyrsia, or the system of telegraphy among the Greeks. --Communication by means of characters and the telescope. --Introduction of the magnetic telegraph between Baltimore and Washington The Kravogl Electro Motor and its Conversion Into a Dynamo Electric Machine.--5 figures Bornhardt's Electric Machine for Blasting in Mines. --15 figures Pritchett's Electric Fire Alarm.--1 figure A Standard Thermopile Telephonic Transmission without Receivers.--Some of the apparatus exhibited at the annual meeting of the French Society of Physics.--Telephonic transmission through a chain of persons Diffraction Phenomena during Total Solar Eclipses.--By G.D. Hiscox