Produced by Juliet Sutherland and the Online Distributed Proofreading Team at www.pgdp.net. [Illustration] SCIENTIFIC AMERICAN SUPPLEMENT NO. 794 NEW YORK, March 21, 1891 Scientific American Supplement. Vol. XXXI., No. 794. Scientific American established 1845 Scientific American Supplement, $5 a year. Scientific American and Supplement, $7 a year. * * * * * TABLE OF CONTENTS I. BOTANY.--New Race of Dwarf Dahlias.--A new and valuable flowering plant, with portrait of the introducer.--1 illustration. II. CHEMISTRY.--Carbon in Organic Substances.--By J. MESSINGER.-- An improved method of determining carbon by inorganic combustions.--1 illustration. III. CIVIL ENGINEERING.--A New Integrator.--By Prof. KARL PEARSON. M.A.--An apparatus for use for the engineer in working up areas, indicator diagrams, etc.--4 illustrations. Best Diameter of Car Wheels.--The size of car wheels from the standpoint of American engineering.--A plea for a moderate sized wheel. Improved Overhead Steam Traveling Crane.--A crane constructed for use in steel works.--Great power and range.--3 illustrations. Some Hints on Spiking Track.--A most practical article for telling exactly how to conduct the operation on the ground.--1 illustration. IV. ELECTRICITY.--Electrical Laboratory for Amateurs.--By GEO. M. HOPKINS.--A simple collection of apparatus for conducting a complete series of electrical experiments.--17 illustrations. The Action of the Silent Discharge on Chlorine.--How an electric discharge affects chlorine gas.--An important negative result. V. ETHNOLOGY.--Some Winnebago Arts.--An interesting article upon the arts of the Winnebago Indians.--A recent paper before the New York Academy of Sciences. VI. MEDICINE AND HYGIENE.--The Philosophy of Consumption. --By Dr. J.S. CHRISTISON.--A review of the present theories of consumption, and the role played in it by its bacillus. VII. MUSIC.--Spacing the Frets on a Banjo Neck.--By Prof. C.W. MACCORD.--A most practical treatment of this subject, with full explanations.--1 illustration. VIII. ORDNANCE.--High Explosives in Warfare.--By Commander F.M. BARBER, U.S.N.--An elaborate review of modern explosives in their applicability to ordnance, etc. The Experiments at the Annapolis Proving Grounds.--The recent tests at Annapolis described and illustrated.--Views of the projectiles, plates, etc.--3 illustrations. IX. PHYSICS.--Araeo-Picnometer.--An entirely novel form of hydrometer, of very extended use and application.--1 illustration. X. TECHNOLOGY.--Fabric for Upholstery Purposes.--Full technical description of the method of producing a new and characteristic fabric.--1 illustration.