Dec. 1, 1804.] THE TECHNOLOGIST. 



ON CHEMISTRY APPLIED TO THE ARTS. 207 



in the same vessel. The distillation of fatty matters, first performed by 

 Mr. Wilson, and since carried by him to a state of perfection, is based ou 

 the fact that, whilst fatty matters, if distilled by direct heat, are com- 

 pletely decomposed, giving rise to the noxious vapours of acroleine, from 

 the destruction of the glycerine, &c, this evil is completely avoided in 

 distilling them by passing a current of superheated steam at a 

 temperature of between 550° and 600° through the mass of melted 

 fatty matters previously brought to the same temperature. By this 

 means the glycerine passes first without decomposition, and is then 

 followed by the fatty acids. In fact, the distillation proceeds with such 

 rapidity and regularity that a stranger might witness the distillation of 

 1,000 gallons in 24 or 36 hours, and all the time would probably sup- 

 pose that water only was distilling. The results are so perfect, that the 

 Jury at the Paris Exhibition of 1855 could hardly credit their genuine- 

 ness, and actually deputed Mr. Warren de la Rue to come from Paris to 

 verify the fact that the beautiful products exhibited were obtained in 

 many instances from very inferior kinds of fat. The glycerine only re- 

 quires redistillation to be fit for all purposes to which it is applied. As 

 to the acids, they are submitted to an intense cold pressure, which 

 separates the oleic acid from the stearic, margaric, or palmitic acids. 

 These are melted, and when near the point of solidification, the vessel 

 containing them is run on rails over the moulds, which are so arranged 

 that each frame contains 200 separate moulds, in which already the wicks, 

 prepared with borax or a salt of ammonia, are fixed. The only 

 remaining operation is to fill the moulds and allow the candles to cool. 



Oleic acid has recently been made available for several valuable 

 purposes : it has been largely employed in the manufacture of soap ; 

 but its most important application as yet is its use on the Continent, 

 and recently in England, as a substitute for olive oil in the greasing of 

 wool for spinning, the advantages of which are marked, as its removal 

 by alkalies in the scouring process is much easier, and its price lower. 

 Messrs. Laing and Wilson have recently taken out a pateLt for the 

 employment of oleate of ammonia as a mordant, and it increases in a 

 marked manner the beauty and brilliancy of the coal-tar colours on 

 cotton. 



It now only remains for me to refer to another interesting process 

 for splitting fatty matters into their elements, I mean that of Mr. Tilgh- 

 man, which consists in mixing fatty matters with one-third to one-half 

 of their bulk of water, and placing them in a vessel capable of resisting 

 a very high pressure. There they are submitted to a temperature of 

 550 deg. and 600 deg. Fahr., and under the influence of that heat and 

 pressure, the fatty matters are decomposed into glycerine and fatty acids. 

 M. Tilghman has also adapted an apparatus which enables him, by 

 means of coils of tubes, to keep up a constant stream of fatty matters 

 and water through the tubes surrounded by fire, by which means the 

 decomposition is rapidly and continuously carried on. 



