FIRELESS ENGINE. A form of steam or vapor engine which is detached from the heating apparatus. Dr. Emile Lanni), of New Orleans, invented July 19, 1870, an engine in which the motive power was derived from the vapor of am monia. The ammonia, as it escaped from the en gine, was passed into a reservoir of water, in which it was absorbed; the water when heated to a temperature of about 135° F. gave up the ammonia as gas, which was returned to the engine to he used over again, and then again absorbed and re turned as before. This engine was found efficient and economical for the movement. of street cars. The use of ammonia was soon abandoned, steam taking its place. Water heated to 212° F. be comes vapor if the pressure upon it be no more than the usual atmospheric 15 pounds per square inch. If the pressure be greater, the water re mains liquid until a higher temperature is reached, the temperature varying with the pres sure according to well-known laws. if steam at a high pressure be admitted to water of low tem perature and pressure in a closed vessel, the steam will be rxmdensed in the water, but the pressure in the vessel will be increased, while the volume of the water will be enlarged by the volume of that derived from the condensed steam. The water thus becomes charged with steam con densed under high pressure, and when the pres sure is relieved, a portion of the steam reverts to its condition of vapor, and may be conducted in the usual way to a cylinder and piston. where
it will do its customary work. The opening of the valves gives vent to the vapor, gradually reduces the pressure, and relieves the condensed steam: so that a tank. filled with water and stored with many times its volume of uncoil d•nsed steam, will furnish motive power suffi cient to move the engine and a considerable train of cars for a trip of several miles. On its return, the tank is connected with a stationary boiler from •hieh it receives a fresh supply of steam. It will not be forgotten that the real force of the steam is due to the heat which it contains, and that if the heat be lost. by radiation or otherwise, from the tank containing the condensed steam, its potential energy is so much reduced. In the en gine used at New Orleans the mechanism was that of an ordinary locomotive minus its fire-box, having a water-tank instead of a boiler; the ap ',Bailees for slopping, starting, and hacking were as usual. The tank Was about G feet long, and 3 feet in diameter, covered thickly with felt and wood to retain its heat. Steam was taken until the gauge indieated 135 to 150 pounds. the tem perature for 135 pounds being 353°. With this accumulation of power the machine ran 5 to 7 miles before the pressure was reduced to 60 pounds. The labor and care of firing is avoided on one of these engines.