All About Engines

The Gas Engine 197 night stoppage of twelve hours amounts to less than 40 lb. The plant can be started again in from ten to fifteen minutes. When bituminous coal is used the plant must be fitted with a tar extractor, otherwise the scrubber would soon get choked up, and the tar would get into the engine and cause trouble. Provided this precaution is taken, then with fuel at 10s. a ton the cost of power amounts to only about one-sixteenth of a penny per horse-power per hour. It is not necessary, however, to use coal at all. Wood waste, sawdust, bark, spent tan, coir dust, coconut shells, mealie cobs, rice husks, sugar-cane refuse, cotton seed, olive refuse, and other material that tends to accumulate and prove a nuisance may be burnt in a gas producer. In this way many industries, especi- ally those concerned with the preliminary processes of manufacture from the products of the soil, can obtain power practically at no cost for fuel, and at the same time get rid of stuff which can only be destroyed by burning. From being tied to the town the gas engine has spread to the outskirts of civilisa- tion, lightening the labour of the pioneer, increasing his output, and providing more cheaply those things for which people in the Old Country have need. During the last twenty years a new source of food for gas engines has been discovered in which fuel is not specially burnt for the purpose at all. The process of obtaining iron from its ore consists essentially in heating the oxide of iron with carbon in the form of coke, using a blast of air to raise the