344 QUARTERLY JOURNAL. 



The general result of these experiments, confirmed by manj 

 similar trials is, that the largest quantity of buttter is produces 

 from the scalded or Devonshire cream ; the next in quantity froi 

 the method of churning the milk and cream together, when thej 

 have become slightly acid ; the third in quantity is afforded h\ 

 cream kept till it is slightly sour ; the smallest quantity is obtain! 

 ed from the sweet cream. We were unable to obtain butter froi 

 churning sweet milk and cream together ; and in several other sc 

 ries attempted it no more. 



In one series of experiments we used as much as 1 H English 

 pints of milk in each experiment ; but we then had to churn in 

 vessels of tinned iron ; and we did not find the results so uniform 

 as when operating on smaller quantities in glass vessels. 



Series 4. 



This series was intended to decide on the qualities of the butter 

 obtained by the four processes above detailed, as to keeping fresh. 

 These experiments were made, as those of the next series, on the 

 butter obtained in most of our experiments. No. 1 always remain- 

 ed, when exposed freely to the air, longer without any rancid taste 

 than any of the other kinds of butter. No. 3 and No. 4 were 

 nearly on an equality in this respect ; if there was any difference 

 it was in favor of No. 3. No. 5 became rancid more quickly that. 

 No. 3 or No. 4. 



Series 5. 



Equal quantities of butter obtained by the four processes wc 

 Salted with equal quantities of salt, then spread thinly on glaS 

 plates, and exposed to the air in a dry room. They were inspec 

 ted from time to time, and it was ascertained that the taint of 

 cidity always appeared in the following order, commencing wU 

 that which shewed it first : — 



In No. 5, or butter from scalded cream. 

 " No. 4, " " a mixture of sour milk and its crea 

 " No. 3, " *' sour cream. 

 " No. 1, " " sweet cream. 



The cause of this difference in their power of resisting dec 

 was believed to depend on the varying proportions of caseine, 

 curdy matter, in each. To determine this point another series c1 

 experiments was undertaken. 



Series 6. 



Two hundred grains of each kind of butter were kept liquifio 

 by a moderate heat, in glass capsules ; the oily matter was take 

 up by bibulous paper successively applied, as long as any oil 

 stain was perceptible ; the watery liquid which remained belo^ 

 the oily matter was evaporated, and the solid residue, after beinf 



