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Previous Next The best candle and soap tips online! TECHNICAL TREATISE OH SOAP AND CAKDLE9. 6APONIFICATION. 165 of soda at 50° B. will have a like beneficial effect. This filling ia added by crutching it into the yet ^varrn finished soap. Grossage was about the first person to propose the ase of Boluble glass as a useful addition to soap, and a3 we have seen above with good effect, but it is sometimes used in excess to adulterate and cheapen genuine and good soaps. It has, however, a detersive power, the free alkali it contains being a solvent of grease and dirt Silicated Boaps are much in rogue, and will be fully described in their proper place, when also other fillings for soap perhaps not so suitable will be mentioned. We have already given some of the characteristics of rosin or colophony, a substance much used in domestic soaps. It consists of the acids, pinic, sylvie, and colophonic, in different proportions, each having an equal affinity for alkalies. To some kinds of soap it givea a useful property, causing a softer consistency, to tallow soap for instance, and so may be considered in the light of an ameliorator. Though readily saponifiable, it does not alone make a useful soap, and when added to other soaps it must not be in greater proportion than fifty per cent, of the fat used, or it will affect its quality. The best results are obtained when it is saponified alone, and added to the other finished soap, while still hot, and thoroughly crutched in. Soap is not entirely soluble in cold water. When used, the alkali is united with the grease and dirt, and the fatty acids are set free and float away, and may afterwards be recovered. In hot water soap will dissolve and form an opaque solution, but the separation occurs when it cools, the solution "becoming clearer, while the fatty acids float upon thesurface. These fatty acids when recovered can be purified and agaiu used to form other soaps. Alcohol dissolves pure soap in all proportions, and on cooling forms a clear jelly. Thia property is utilized to make various transparent soaps. Some writers in our art advise the forming of the neutral fats into sebacic acids, and then saponifying with carbonated alkalies, but unless the saving of the glycerine is an object there is little economy in the method, for the saponi float ion with carbonated lyes ia a tedious process, and the escaping carbonic acid causes a great deal of foam, and it takeB much more time than boiling with the usual caustic lyes. Moreover, the soap so made is never as good, as it always retains a spongy condition, and dissolves too easily in water. So it will be unnecessary to say that all these processes or methods, having in viaw the avoidance of caustic alkalies in manufacturing soap, have signally failed ; as the making of soap is founded upon true chemical principles, and oa well-established rules, so that it is hazardous for any one to depiatefrom methods founded upon such long and well tried experience. Yet let it not be supposed that there is nothirg more to learn. On the contrary, the experiments of experts are con stantly throwing new light upon the art, which with the invention of new appliances has, in a remarkable degree, improved the quality of nearly all soaps in use. But what is already known is founded upon sound principles, and it would be a loss of time and money for a novice to experiment in the direction already covered by those long accustomed to the subject, and when experience founded on science may be taken as the best guide. Yet as we recognize that the art of the fabrication of soap is a progressive one, and new and.utitried materials are constantly being discovered that might find useful or economical application in it, so the enterprising manufacturer will always be on the alert, to endeavor by new means or new materials to improve his processes, or produce new goods. 166 TECHNICAL TREATISE OS SOAP AND CANDLES. SECTION VIII. ALKALIMETRY. THE proper knowledge of the constituents of the alkalies used, with tneir preparation for the decomposition of the neutral fats or the sebacie acids, is beyond all doubt the most important in the art of making soap; and the difficulties attending the attainment of this knowledge are not so great but that it can be easily acquired by any one having an ordinary understanding of the principles upon which it is baaed, or sufficient intellect to comprehend the commonest elements of chemistry. From carelessness or ignorance many errors are committed, and much time and labor are lost by mistakes that the correct attainment of the manner of chemical analysis or assay of the alkalies would tend to avoid. The acquirement of a thorough chemical knowledge is scarcely to be expected of men whose time haa to be employed in another direction : yet it 13 most important that the chemical actbn of the materials applicable to the fabrication of soap should be well studied. To this end the author will try to give the most simple and correct methods for the testing of the alkalies. The alkalies of commerce are never pare, bit contain, besides carbonates, sulphates, sulphites, chlorates, etc., so that the object of alkalimetry is to determine the percentage of caustic or carbonated alkali a potash or soda of commerce may contain. The principles of this test are based upon the law of equivalents, wHch is illustrated elsewhere, and which means that a certain definite weight of a reagent ia required to saturate or neutralize an equivalent of a b&se. So, on the variations in the quantity of pure alkali contained in Previous Next
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