478 Dr. Playfair on Palmic Acid. 



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Hence the acid has altered in composition during saponi- 

 fication. A silver salt was now prepared in the manner pre- 

 viously described. 



0*3195 grm. substance left on ignition 0-0885 silver. 



0*1785 grm. substance, burned with oxide of copper, gave 

 0-3425 carbonic acid, and 0*133 water. 



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The silver salt is therefore of the same composition as that 

 made from the acid analysed before saponification. The only 

 alteration is in the assumption of an atom of water during the 

 separation from the soap, as will be seen from the following 

 theoretical composition : — 



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Hence the palmic acid procured by decomposing palmate 

 of potash differs only in its assumption of an atom of water. 

 Its formula is HO, C^ H 32 O s , the water being displaced by 

 oxide of silver during the formation of the silver salt. 



Palmate of Lead. — A solution of palmate of potash poured 

 into a solution of acetate of lead causes the precipitation of a 

 basic salt, which was analysed, but appears to be of no definite 

 composition. 



Palmate of Barytes. — This salt Mas made by precipitating 

 palmate of potash with chloride of barium, and washing the 

 precipitate first with water, then with alcohol. It is a white 

 powder with a soapy feeling to the touch ; it is insoluble in 

 water. 



0*391 grm. of the salt yielded 0*1275 sulphate of barytes. 



0*547 grm. salt, burned with chromate of lead, gave 1*164 

 carbonic acid, and 0*448 water. 



