One of the most generally adopted methods of enrichment now is by means of carburetted water gas mixed with poor coal gas.
The following analysis gives a fair idea of the composition of an average sample of gas made from coal, purified but without enrichment: Ioo 00 These constituents may be divided into - (a) light-yielding hydrocarbons, (b) combustible diluents and (c) impurities.
Undoubtedly the best process which has been proposed for the production of oil gas to be used in the enrichment of coal gas is the" Young "or" Peebles "process, which depends on the principle of washing the oil gas retorted at a moderate temperature by means of oil which is afterwards to undergo decomposition, because in this way it is freed from all condensible vapours, and only permanent gases are allowed to escape to the purifiers.
The universal adoption of the incandescent mantle for lighting purposes has made it evident that the illuminating value of the gas is a secondary consideration, and the whole tendency now is to do away with enrichment and produce a gas of low-candle power but good heating power at a cheap rate for fuel purposes and incandescent lighting.
The inspiration of early belief has disappeared; the ruling motive of the mollahs (priests) is the thirst for personal enrichment, and the people no longer follow the khojas or theologians.