Dec. 1, 1864.] THE TECHNOLOGIST. 



ON CHEMISTRY APPLIED TO THE ARTS. 203 



tity of water can be introduced to weight it, because this would cause 

 the separation of the mottling material from the soap. Fancy soaps are 

 prepared in the above maimer, by the employment of a better quality 

 of materials and the addition of various perfumes. Rosin or yellow soap, 

 as its name implies, is one in which a portion of the fatty matters is re- 

 placed by rosin, which is added to the soap paste when there is but 

 little acpieous solution of alkali left to dissolve it, so that the rosin can 

 at once enter into the composition of the soap, instead of being dis- 

 solved in the alkaline lye and lost. Rosin soaps, nearly white, are now 

 manufactured, owing to the discovery of Messrs. Hunt and Pochin, 

 who have succeeded in obtaining nearly white rosins by distilling 

 common rosin with the aid of superheated steam. Silicated soaps are 

 much used in America, owing to their cheapness, which is due to the 

 introduction of a certain amount of silicate of soda. Transparent soap, 

 the method of making which was so long kept secret, is now known to 

 be obtained by dissolving soap in alcohol and allowing a concentrated 

 solution of it to cool slowly, when it is poured into moulds and allowed 

 to solidify. One of the most useful and recent improvements in soap- 

 making is that which enables the manufacturer to produce what is called 

 glycerine soap, which is characterised by the retention of the glycerine of 

 the fatty matter. Its manufacture only occupies a few hours, instead of 

 several days, as is the case with ordinary soap. It is prepared by employ- 

 ing 63 parts of fatty matter, 33 of water, and 5 of alkali, which are heated 

 to a temperature of between 350° and 400°, for two or three hours, 

 when the mass is entirely saponified, and then has only to run into 

 moulds to be ready for the market. But the most important discovery 

 connected with the saponification of fatty matters by means of alkali is 

 that recently made by M. Meges Mouries, for this gentleman has arrived 

 at the remarkable result of saponifying fatty matter in the space of twelve 

 hours, and, what is more extraordinary still, at natural temperatures. 

 If we connect this fact with the one that caustic soda is now manufactured 

 by tons, it appears highly probable that in a few years the fatty matters 

 of Buenos Ayres and Monte Video, instead of being sent to this country 

 as such, will be converted into soap there, and imported thence by us 

 in that form. M. Mouries has discovered that fatty matters are sus- 

 ceptible, under peculiar circumstances, of being brought into a globular 

 state, and that when in that state they present new and peculiar proper- 

 ties. Thus, for example, fatty matters, when kept in a damp condi- 

 tion, usually become rapidly rancid, whilst when in the globular 

 state they may be kept for a very long period without undergoing 

 that change. This peculiar state can be imparted to fatty matters 

 by melting at 113° and adding a small quantity of yolk of egg, bile, 

 albuminous substances, or, what is best, a solution of alkali, composed 

 of five to ten parts of alkali for every 100 parts of oil, at the same 

 temperature, agitating the whole for some time to bring the fatty 

 matter into a tdobular condition. If at this stage the action of the 



