Memoir on the Nature of fat SiibslaiiQes^ 31 



\varm water the grav paper, in which tlie butter had been com- 

 pressed ; then 1 made a ball or knot of it, which was submitted 

 to the action of the press, and there resulted an oil perfectly 

 fluid. We may also obtain a part of the oil of butter by pouring 

 it into a vessel furnished at its lower pai-t with an aperture 

 which is to be uncorked when the butter freezes : after some 

 time, and at a moderate temperature, a considerable quantity of 

 the oil flows out, which may be advantageo\:5lv used in the pre- 

 paration of certain dishes. The oil of butter obtained at a low 

 temperature is a liquid of a yellow colour, like most of the fixed 

 vegetable oils, of a smell and a taste peculiar to the butter. 1 

 had tried, but without success, to take off from this oil its co- 

 louring matter, by treating it with ether. The sulphuric acid 

 when properly employed seems to destroy this yellow colour, for 

 the oil becomes colourless, particularly after having been treated 

 with a little argil. 



One hundred parts of melted butter of a good quality made 

 during summer, yielded as a product at the temperature of 

 zero: 



Oil ,. GO 



Suet 40 



100 

 But these proportions are liable to variation, according to the 

 physical constitution of the cow, the nature of her food, and the 

 place where she is domiciled. Thus the butter v,hlch is brought 

 to us from the Vosges mountains is of a fine yellov/ colour; it 

 is much more oily and more esteemed than that which is pro- 

 cured in plain or low countries, which last is paler, firmer, and 

 contains more suet. This last substance is still more abundant 

 if the cows have beau fed upon dry forage ; when they furnish a 

 hard, compact butter, of a dull white and of an inferior qualitv. 

 One hundred parts of this winter butter from the Vosges yielded 

 at the temperature of zero. 



Oil 35 



Suet fjj 



100 

 We see by these respective quantities the enormous difference 

 between summer and winter butter : but if the proportion of sue' 

 and oil varies in the same animal, according to different circum- 

 stances, a fortiori, ought it to vary in the different kinds of ani- 

 mals which yielded it. To judge from its consistence, the but- 

 ter of cows and goats ought to contain a nmcli greater quantit / 

 of suet than that of sheep, asses, and mnres. That of vvoine;: 

 ^L'enis to be entirelv f'trmod of oil. 



