Lenoir Kinder & Kinsey Hugon Ravel Turner Bénier Parker Hutchinson Forest Baker Economic motor Crown Laviornery Lentz Group II. Explosion with compression. (1) _Two-cycle type._ Dugald-Clerk Koerting-Lieckfeld Wittig & Hees Andrews (Stockport) Benz Ravel Baldwin Taylor (Midland) Campbell Bénier (2) _Four-cycle type._ Millon Otto Linford Crossley Maxim Martini Lenoir Simplex Koerting-Boulet Lombard Durand Daimler Varchalouski Atkinson Tenting Diedrichs Adam Ragot Forest Noël Charon Niel Lablin Poussant Roger Letombe Lacoin Cronan Cadiot Dürkopp Brouhot Levasseur Fielding Delahaye Acmé Cuinat Group III. Combustion with compression. Brayton Hoch Simon, et fils Livesay Crowe Gardie Overmand Group IV. Atmospheric motors. Otto & Langen Bisschop Gilles Hallevell Robson François Carburetted Air Engines. Lenoir Forest Tenting Daimler Le Marcel (Cadiot) Durand De Dion-Bouton Bollée Pelloree Le Pygmée Klause Oil Engines. Brayton Priestman Ragot Otto Crossley-Holt Niel (Atlas) Hornsby-Akroyd Grob-Capitaine Merlin Knight-Weyman Griffin Pinkney Levasseur Root Rationnel Dawson The “Gnome” On page 21 we give a table embracing all the best known types of gas engines, which will also help to avoid the confusion arising from the fact that some motors exist which belong to neither one nor another, but are combinations of one or more groups. Such hybrid motors have been devised amongst others by Schweizer and Siemens. In the former the power of the explosion is used to compress a considerable volume of air, which is then used for working a compressed air engine. In the latter the gas heats a quantity of air which drives a hot-air motor. In this table we have also, specially grouped apart, engines using carburetted air (air which has been passed through a volatile spirit such as benzoline) and petroleum. The list may be found somewhat incomplete, as more than 250 gas engines have been devised and patented in the last twenty-five years; but on the other hand, many of these have been failures, and we have only included those motors which can undoubtedly be considered commercial successes. These we will now study. CHAPTER III DESCRIPTION OF EXISTING GAS ENGINES