ON THE PROCESSES FOR CLARIFYING LIQUIDS. C 25l 



Frefh cream is advantageoufly ufed to clarify fpirituou's Cream ufed to 

 liquors. One or two fpoonfulls for each French pint or 

 Englifli quart are fufficient to produce this effect, without 

 heat, in the courfe of a few hours. But as in this clarification 

 there always remains fome cheefy particles fufpended in the 

 fluid, on account of their great fubtilty, it is neceflary to 

 complete the procefs by fubfequent filtration* 



Laftly, there are fluids which, in order to become clear. Mere heat* 

 require only to be heated nearly to the boiling point. Thele 

 are principally fuch as owe their opacity to fubftances which 

 cannot be completely diflblved, unlefs the temperature of the 

 folvent be raifed confiderably above the natural ftate. Many 

 faline folutions are in this cafe, and thofe who are bufied in 

 chemical refearches have frequent opportunities of obferving 

 them. 



Mofl of the juices of plants newly exprefled may be partly Clarifies the 



clarified by heat. The chemiit is therefore in the habit of re-J uices tff***'* 



. . ... &c. 



curring to this method with refpect to the juices which, on 



account of their denfity and vifcidity, are not capable of being 



filtered. 



It frequently happens that a very /light degree of heat, ap- Vegetable albu- 

 plied to exprefled and filtered juices of certain plants, w iH men precipitated, 

 render them at once turbid ; in which cafe the flocculent mat- 

 ter that floats in the liquid fettles at the bottom of the vefleh 

 This fubflance was confldered by Rouelie the younger as the 

 vegeto animal matter of wheat; but I fhewed, in 1772, that 

 it is a fubftance fimifar to the white of egg : which proves 

 that we were authorized at that period to reckon the albumen 

 among the produces of the vegetable kingdom. 



I rauft infill: on an important obfervation, that in general Caution again 

 it is neceflary to feparate the magma which is formed in ^albumen! ° f 

 liquors clarified in albumen, particularly when in order to 

 concentrate thefe fluids it is neceflary to evaporate them by 

 boiling. Without this precaution we fhall fee the fame 

 magma diflblve, and the fluids become more turbid than they 

 were before the clarification. For a like reafon it is that 

 foups, which have not been flammed in time, always retain a 

 cloudy and unpleafant appearance. 



Though the ufe of albumen to clarify the juices of certain In what cafes 



vegetables is confiderable, it is not, however, exempt from finin ?^ tha i b , u * 

 ~ c , r . . . r , . men is hurtful, 



inconvenience. One or thele inconveniences is, that it 



Vol. L— April, 1802. S changes 



