Dyspepsia, its causes and prevention.--How this malady is caused and how easily it may be guarded against, an essay in prophylaxis 10610 IX. MECHANICAL ENGINEERING.--Coal Tar as Fuel for Steam Boilers.--By JOHN McCRAE, of Dundee.--A review of the economy of tar firing and of the method employed by the writer.--1 illustration 10604 Steam Generator of Serpollet Brothers, producing steam instantaneously.--A new inexplodible steam generator, its construction and application to a tricycle.--3 illustrations 10602 Transmission of Power between Bodies Moving at Different Velocities.--A simple system of transmitting power applicable in many places 10602 X. MISCELLANEOUS.--Note on Missouri Marble 10614 Water Blast Pump.--A filter pump of simplified and improved construction.--3 illustrations 10602 XI. NAVAL ENGINEERING.--Iron Sailing Ships.--Scotch sailing ships, built of iron and steel, the favorite sizes and rigging adopted.--1 illustration 10602 XII. SANITARY ENGINEERING.--Putzeys' Flushing Reservoir.--A French invention, applicable in sewage disposal and pipe flushing.--1 illustration 10611 XIII. TECHNOLOGY.--Gas Lighting by High Power Burners.--A review of a number of regenerative and other gas burners and their practical success 10603 Synchronizing Clocks.--A simple synchronizing mechanism described and illustrated.--1 illustration 10604 Watch Cleaning and Repairing.--A long paper treating of the details of watch cleaning from the practical standpoint 10604 * * * * * [Illustration: GUN PRACTICE IN THE FRENCH NAVY.] GUN PRACTICE IN THE FRENCH NAVY. The gunners of the French fleet are possessed of a skill which is recognized by all the maritime powers, and these picked men proved this at the siege of Paris, where they made themselves illustrious, not only by their courage and their coolness, but also by the accuracy of their firing.