All About Engines

T94 All About Engines supply of air, and poker holes in the top to enable the red-hot fuel to be stirred occasionally. At the meeting of the British Association for the Advance- ment of Science, at York, in 1881, it was shown driving a 3-horse-power gas engine, and created a great deal of interest. It occupied no more space than a boiler and produced no smoke, burning the coke completely away to fine ashes, which were raked out at the bottom from time to time. A gas with a greater calorific, or heating value, free from nitrogen, can be obtained by passing steam through red-hot coke. The result in this case is a mixture of carbon monoxide and hydrogen. Unfor- tunately, the steam would soon put the fire out, so the process has to be stopped every few minutes while air is blown in to raise the temperature again. In spite of the fact that the process is intermittent, water gas, as it is called, has been made in gasworks for many years for mixing with coal gas. The carbon- dioxide gas, formed when air is blown through, is allowed to escape into the atmosphere, and the water gas alone is employed for this purpose. To the student of chemistry the equation C + H2 O = C O + H2 will again be familiar. A tremendous advance was made in 1889 when Dr. Ludwig Mond found that if air and steam were used together a mixture of producer gas and water gas was obtained, which was better than producer gas, while the process could be worked continuously. He found, moreover, that small coal, which is cheaper than