64 THE DAIKY OF THE FARM. 



Essentially, butter is composed of solid and liquid fats, 

 margarine and elaine, and in addition to these oils, there 

 may be present in very small and varying quantity, a 

 number of other substances, of fragrant, or, some of them, 

 of fetid odour. They are derived from changes produced 

 in the sugar of milk and in the oils of butter processes 

 accompanied by the absorption of the oxygen of the air 

 which are excited and maintained by the presence of the 

 cheesy part of the butter, which is here most liable to be 

 acted on by ferments, just as it is in milk itself. 



Cream forms a proportion of milk, varying according 

 to the richness of the whole fluid, and the poorness of the 

 remainder. And there are as many proportions between 

 the one and the other as there are instances in which the 

 point has been ascertained. 



The following is from a correspondent in Gloucester : 

 20 quarts of milk in hot weather yield If quarts of cream, 

 or about 9 per cent.; and one-fourth more, or 11 per cent., 

 in colder weather. In Mr. Williams' dairy, Co. Cork, the 

 average of the year's milk produced 12 per cent, of cream 

 12 pints of cream and rather more than 5 Ibs. of butter 

 per 100 pints of new milk. The average yield of Mr. T. 

 Scott's English dairies, quoted some years ago before the 

 Agricultural Society, was 1 quart of cream for every 12 

 quarts of milk, or little more than 8 J per cent, of a cream 

 yielding 15 ozs. of butter per quart. In Mr. Horsfall's 

 dairy, to which reference has already been made, the cream 

 did not exceed 6J per cent, of the milk. 



Some of the differences thus observed are no doubt 

 owing to original differences in the quality of the milk ; 

 but this last case is due to an extraordinary density of the 



