Memoir on llie Nature of fat Substances. 39 



gree of heat, according to Bostock ; but this suet is less soluble 

 than wax, and than the white fat of whales in boiling alcohol. 

 The latter may, however, dissolve to make the liquor tuibid on 

 cooling. Boiling ether dissolves it better, and upon cooling a 

 precipitate is formed in large gelatinous flakes. 



Pure beef suet is white, although having naturally a yellow 

 colour when it is not purified, which makes it be supposed that 

 this colour is owing to oil: it has a greasier aspect than mutton 

 suet; it is besides more fusible, suice it is liquefied at 4G° R. 

 Thus it is less adapted for candles than pure mutton suet, which 

 jvhen obtained by some easy process will afford tlie means of 

 supplying the place of wax in some circumstances. 



In order to complete what I have said as to suet, I shall enter 

 upon some details respecting its singular metamorphosis into 

 several fat substances by the action of the acids and alkalies, 

 which will lead me to examine the results of saponification and 

 •rancidity. 



Action of the Sulphuric Acid upon Suet. 



Chemists have contented themselves with saying, that the sul- 

 phuric acid decomposes and carbonizes fat, particularly with the 

 aid of heat ; but it does not appear that they have examined 

 with care the results of this action. If we pour concentrated 

 sulphuric acid into melted suet, there is immediately formed by 

 agitation a true combination, in which the acidity basin a great 

 .measure disappeared. To one part of melted mutton suet was 

 added half a pint of sulphuric acid, and the combination, which 

 .was of a reddish colour, was diluted in a great quantity of boil- 

 ing water, which seized tlie sulphuiic acid and abandoned the 

 greasy matter. The latter, aiter having beea washed several 

 times, had not perfectly lo«t its weight, but it had acquired a 

 less firm consistence than the suet employed : the latter was in 

 fact transformed into a small quantity of oil, and into a substance 

 very analogous to wax. In order to isolate these two substances 

 from each other, the oleo-cirous mass, when well cleansed from 

 sulphuric acid, was melted^ and the half of its weight of alcohol 

 was added to it ; the union took place immediately with a 

 promptitude truly extraordinar\': upon cooling there resnlted .1 

 hard mass, which was folded in new linen ; by gradual pressure 

 the alcohol was expelled charged with oily matter, and the com- 

 pression was finished in gray ):/aper. The solid matter thus ob- 

 tained was not yet perfectly white, although treated several times 

 with alcohol ; but by means of warm ether, which also dissolves 

 it with extreme facility, we succeed much better in obttiining it 

 cf a perfect whiteness. This substance is dry, sonorous like 



C4 hard 



