The Romance of Modern Chemistry

THE VALUE OF THE BY-PRODUCT manageable rate, and it is no wonder that manufac- turers and their chemists have made heroic attempts to deal with this rubbish problem. Indeed, the story of the way in which the attacking forces have slowly advanced, at great expenditure of energy, patience, and fortune, reads like a romance. The reader, however, will readily understand that besides the mere wish to avoid the awkward accumula- tion of rubbish, the desire to make something out of it has helped in the solution of the problem. The manufacturer is only too pleased if the chemist can tell him how waste material can be converted into a useful by-product. Indeed, history shows that the dis- covery of methods for utilising the waste products of a chemical industry has frequently saved it from going down in the face of fierce competition. Economy demands some utilisation of the waste material, and this has been effected with much profit to the manufacturer even in industries where there is no particular difficulty in getting rid. of it. An instance of the production of much waste material is to be found in the brewing industry. The main object of brewing is, of course, to get beer, but during the process of manufacture a very large quantity of carbon dioxide is produced. The alcohol in the beer is obtained by the fermentation of sugar, in which process sugar is changed into alcohol + carbon dioxide. The quantity by weight of the carbon dioxide formed during the fermentation is almost equal to that of the alcohol, and the process is generally carried on in open vessels, so that the gas simply escapes into the air, and is lost. Carbon dioxide, that is to say, is a waste product of the brewing industry. 270