[Illustration] SCIENTIFIC AMERICAN SUPPLEMENT NO. 803 NEW YORK, May 23, 1891 Scientific American Supplement. Vol. XXXI., No. 803. Scientific American established 1845 Scientific American Supplement, $5 a year. Scientific American and Supplement, $7 a year. * * * * * TABLE OF CONTENTS. I. ASTRONOMY.--The Great Equatorial of the Paris Observatory.-- The new telescope recently put in use in Paris.--Description of the instrument and of its effects.--3 illustrations II. CHEMISTRY.--An Apparatus for Heating Substances in Glass Tubes under Pressure.--By H. PEMBERTON, Jr.--A simple apparatus for effecting this purpose, avoiding risk of personal injury.-- 2 illustrations Table of Atomic Weights.--A revised table of atomic weights, giving the results of the last determinations, and designed for every-day use Testing Cement.--A laboratory process for testing Portland cement III. CIVIL ENGINEERING.--The Compressed Air System of Paris. --An elaborate review of this great installation for the transmission of power.--The new compressed air station, with full details of performances of apparatus, etc.--10 illustrations IV. ENTOMOLOGY.--Report on Insects.--Continuation of this report on noxious insects.--Their habits and how to cope with them. --18 illustrations V. FLORICULTURE.--Lily of the Valley.--Practical notes on the cultivation of this popular flower.--How to raise it and force the growth VI. MATHEMATICS.--The Conic Sections.--By Prof. C.W. MACCORD.--Examination of the four conic sections with a general definition applicable to all.--6 illustrations VII. MECHANICAL ENGINEERING.--The Builders of the Steam Engine--The Founders of Modern Industries and Nations.--By Dr. R.H. THURSTON.--Prof. Thurston's address before the Centennial Celebration of the American Patent System at Washington, D.C.--The early history of the steam engine and its present position in the world VIII. MISCELLANEOUS.--The Breeds of Dogs.--Popular description of the different breeds of dogs most affected by amateurs.--6 illustrations IX. NAVAL ENGINEERING.--Modern Armor.--By F.R. BRAINARD.--The development of modern ship armor, from laminated sandwiched and compound types to the present solid armor.--9 illustrations X. PISCICULTURE.--Restocking the Seine with Fish.--The introduction of 40,000 fry of California trout and salmon, designed to restock the Seine, depopulated of fish by explosions of dynamite used in breaking up the ice.--1 illustration XI. RAILWAY ENGINEERING.--Improved Hand Car.--A novelty in the construction of hand cars, avoiding the production of a dead center.--1 illustration