The Romance of Modern Chemistry

MORE ABOUT FUEL difficult to bum. In domestic use it must be mixed with coal, but in furnaces where there is a powerful draught, it is very satisfactory by itself and gives off no smoke. Large quantities of gas coke are employed in lime and cement-burning. Such are the chief products of the destructive distilla- tion of coal in the manufacture of coal gas. As a fuel, coal gas, if not particularly cheap, is comparatively clean, and certainly very convenient. Hitherto it has been used principally for lighting purposes, and we can best appreciate its convenience in that respect fiorn the standpoint of our great - great - grandfathers. What seemed to them the marvel about coal gas was that no wick was required as in the lamps and candles with which they were familiar. So marvellous did they find it, that it was regarded as rather uncanny, and the lighting of gas lamps was at first thought to be a perilous undertaking. Nowadays, electricity is a competitor with gas as an illuminant, but the latter is being increasingly employed as a fuel, and may be said to hold its own. In England there is a decided preference for the old-fashioned, cheery open coal fire, with all its accompaniments of ash, soot, and smoke; there is little doubt, however, that the gas fire or stove is gradually coming into favour on account both of its cleanliness and its convenience. In estimating the chances that coal gas will hold its own with electricity as a lighting and heating agent, the very important part played by the by-products of the gasworks must not be forgotten. Here, as in so many cases, it is the by-products which settle the question whether a given manufacture will pay or not. Coke, which has been referred to as a by-product in 148