]^70 BULLETIN 173, U. S. NATIONAL MUSEUM 



side and a large opening at the center, through which the mixture 

 of air and gasoline passes to the engine. Rising vertically from the 

 center of the bottom of the chamber is a hollow tube or jet connected 

 to the bottom of the float chamber, so that gasoline stands in the 

 tube at the level of the gasoline in the float chamber. Surrounding 

 the jet is a hollow barrel valve controlling the volume of the mixture 

 that can pass to the engine. Air enters the bottom of the chamber 

 and sweeps uj) and around the jet, drawing a spray of gasoline mixed 

 with the air into the engine. An adjusting screw operates a needle 

 valve at the tip of the jet to control the richness of the mixture. 



HAYNES-APPERSON MIXING VALVE, c. 1900 



U.S.N.M. no. 262135; original; gift of Elwood Haynes; not illustrated. 



This carburetor is part of the equipment of the Haynes automo- 

 bile of 1893, as it is now exhibited in the Museum. This type of 

 carburetor was patented by Elwood Haynes, May 30, 1905, Patent 

 no. 791192. 



This is typical of the class of carburetors known as mixing valves. 

 In it gasoline flows by gravity to the seat of a flat conical (mixing) 

 valve, which is caused to open by the suction of the engine piston, 

 allowing the gasoline to spray over the valve and mix with the air, 

 which is drawn past the valve into the engine. 



In this carburetor gasoline flows to the mixing valve through a 

 needle valve, which is adjustable to control the rate of flow of the 

 gasoline. Air enters the mixing chamber by way of a gate valve. 

 The same lever controls the needle valve and the air valve, opening 

 or closing both together. This lever was controlled by a pedal on 

 the dash of the machine. As used, gasoline flowed to the carburetor 

 from a small tank above it, which was filled from the main tank 

 by a small pump operating from the engine shaft. 



"AUTOCAR" CARBURETOR, 1901 



U.S.N.M. no. 307257; original; gift of the Autocar Co.; not illustrated. 



This is a float-feed, constant-level, induced-jet carburetor of early 

 and very simple construction. It is a part of the Autocar automobile 

 of 1901, as exhibited in the Museum. 



This carburetor, which is of cast aluminum, is constructed in two 

 compartments, the float chamber and the mixing chamber. A cork 

 float operates a needle valve in the gasoline feed line to maintain a 

 constant level of gasoline in the float chamber and in the jet in the 

 mixing chamber. Air is drawn through the carburetor by the suction 

 induced by the piston of the engine and by inspirator action draws 

 a spray of gasoline from the jet. The mixture passes out of the car- 

 buretor to the engine manifold by way of a rotary-barrel type of 



