Britain at Work
A Pictorial Description of Our National Industries

 BRITAIN AT WORK. SOAP BOILING ROOM. has made great headway in the toilet soap business, and so marked has been this advance that the premier position of France is seriously threatened. Before proceeding to an inspection of a great soap factory, something must be said of the chemistry of the subject. Prior to the researches of the French scientists, Leblanc and C hevrcul, the manufacture of soap was largely haphazard ; it was certainly wasteful. I o Leblanc’s process for the manufacture of soda from common salt the soap-maker probably owes more than to any other thing. Chevreul’s achievement was to analyse the constituents of fatty bodies and to discover the process for their separa- tion. As a result, the industry was placed upon a scientific basis. It would, of course, be out of place to enter into details regarding the technicalities of the subject. Besides, there are soaps innumerable, each differing in some particular from the other; thus the technical aspect becomes a very large one. Then, too, the soap-maker, who is not the least shrewd among men of commerce, is not disposed to reveal the secrets of his trade. But with- out indulging in the mysteries of chemical phraseology, some idea can be given as to what goes to make the soap we daily use. In thus limiting ourselves, we need have no fear of divulging trade secrets, for, after all, the ordinary constituents of soap are things of common knowledge. For hard soaps, tallow and the more solid vegetable fats are chiefly used, while for soft soap seed or fish oils are the principal ingredients. These fats, it may be necessary to explain, are mixtures of salts with glycerine as a base. Now by acting upon the fats either with soda or potash the glycerine is removed, and the remaining fatty acids unite with the soda or potash to form soap. For hard soap the agent employed to separate the glycerine from the fatty acids is soda, and for soft soap potash. Though really the chief cleansing constituents in soap, these alkalies, soda and potash, are by themselves very destructive. The fatty acids are thus the coating of the pill; or rather, it should be put, they neutralise the effect of the alkalies, which consequently carry out their cleansing mission without harm to the article under treatment. Soap has been usefully defined as a sort of magazine of alkali which it gives up in the exact quantity required at any moment when it is rubbed with water. Bad soap is that which sets free the cleansing but injurious alkali too rapidly. A good soap frees the alkali slowly, and accomplishes its work in happy union with the fatty matter, which has a certain effect in preparing the way for the alkali. It comes about, therefore, that the object of the soap manufacturer must be to bring about such a blending of alkalies and fatty acids that in the completed article the dangerous elements, while suffi- ciently powerful for cleansing purposes, will be so far neutralised as to be innocuous. Apart from the alkalies, the ingredients which go to the making of soap hail from the four quarters of the globe. Tallow, which is the most important of the fatty acids employed, comes from Russia, Australia, and the Americas—from the cattle-reariri0- countries, in fact. Then among the oils used are those derived from the palm, the palm kernel, cocoa-nut, the olive, ground nut,