C 310 ] 



tion to try. However, I took it for granted, and 

 imputed it to the alcaline fait contained in the 

 compofition of the foap. Hence I conceived, 

 that fome chemical preparation of an oppolite 

 quality might produce as oppofite an effedl. I 

 could think of nothing fo likely to anfvver this 

 purpofe, and at the fame time fo innocent, as the 

 vegetable acetous acid. Accordingly, when the next 

 operation of churning had been going forward for 

 half the day, I caufed a little diftilled vinegar to be 

 poured into the churn, and the butter was produ- 

 ced within an hour afterwards. It has fince been 

 regularly made ufeof for this purpofe, and always 

 with the delired fuccefs. 



If the fuppofition be admitted, that the cream 

 of old milk (and fuch is milk for the mofl: part at 

 this feafon) contains much ftronger alcaline fait, or 

 at leaft more of it than new milk does, then the 

 effedl of the vinegar is readily accounted for on 

 the known principles of chemiftry. It is an ac- 

 knowledged property of alcalies to unite with oil 

 into a faponaceous mafs, and to render them inti- 

 mately mifcible with water. But it is likewife well 

 known to chemifts, that there is a nearer affinity, 

 (as they term it) a much ftronger eledlive attraclion 

 between acids and alcalies^ than between alcalies 

 and oils. Confequently, the acid, being mixed 



with 



