The Romance of Modern Chemistry

THE VALUE OF THE BY-PRODUCT which Leblanc devised laid the foundation of an enormous industry, and has given us cheap soap and cheap glass; but he himself, poor man, did not have much joy out of his invention. The unsettled nature of his time prevented his getting any profits; he did not even receive the reward promised by his own Government, and at length, in disappointment and despair, he put an end to his own life. Leblanc’s process for the manufacture of soda has been worked in England for about ninety years, and in order to appreciate its strange and chequered history, we must understand what the process is. The first stage is the conversion of common salt (chloride of soda) into sulphate of soda, or “ salt cake,” as it is called, by heating with sulphuric acid. This operation results, not only in the formation of salt cake, but also in the evolution of torrents of hydrochloric acid gas. While the industry was in its infancy the hydrochloric acid had little or no value, and was allowed to go up the chimneys and pollute the air. The results of this were remarkable; the vegetation in the neighbourhood of the alkali works was devastated; the smell pervading the atmosphere was noxious, and articles made of iron, such as locks, gutters, and tools, were rapidly corroded. No wonder that the alkali works were unpopular institutions. The manufacturers thought that by building very high chimneys, up to 500 feet, the acid gas would get dis- sipated in the upper layers of the atmosphere, but this plan did not work out in practice, for the fumes descended like a pall on still wider areas, and the vegetation vanished. A striking commentary on the anxiety there was about 1840 to get rid of this public nuisance is furnished by the patent which was taken out for a sort of floating 274