152 SCIENCE AND PRACTICE OF DAIRYING. 



number of the separators in use ought to be taken into account. In 

 every well-conducted dairy, exact details ought to be noted daily and 

 entered into suitable tables, with regard to all the more important condi- 

 tions, and also with regard to the success of the work. By means of 

 such details, which permit of the slightest irregularities and their causes 

 being clearly traced, the work attains a high measure of efficiency. The 

 nature of these details may be best illustrated by the table on p. 151. 



If, for example, in the week under discussion, 12,132 kilos, of milk 

 have been treated and 450 kilos, of butter obtained, there would be used 

 for every -kilo, of butter 26 -6 kilos, of milk, or for every 100 kilos, of milk 

 3*75 kilos, of butter. The quantity of butter (B) which, under ordinary 

 treatment, can be obtained from milk, with an average fat percentage (/), 

 can be found by the following simple formula : 



B = ri6x/--25; e.g. B = 1'16 x 3'4- -25 = 3'69 kilos. 



Since, in point of fact, 375 kilos, of butter were obtained from 100 

 kilos, of milk with 3*45 percentage of fat, the success of the yield is 

 thoroughly satisfactory. By means of the formula given, one can calcu- 

 late, therefore, provided the average percentage of fat in the milk, which 

 has been churned, and the yield of butter per 100 kilos, of milk is known, 

 whether the yield comes up to the required standard or not. 



77. The Forces which are brought into Operation in the Action of 

 Separators. In dairies in which 1000 kilos, of milk and more have 

 to be treated daily, separators are worked only by steam. It may 

 be generally affirmed that the application of steam pays, if, on an 

 average, 300 kilos, of milk are daily treated. If a smaller quantity 

 of milk has to be treated, hand-separators may be used, if it be not 

 possible to form a branch of a co-operative dairy company. In 

 smaller separating dairies, that is, in those in which 300 to 1000 

 kilos, of milk are creamed, it is doubtful whether steam or winch or 

 the application of some minor motor petroleum or hot-air machine 

 is best. There are cases in which the winch is very suitable. 

 On the whole, however, steam is cheaper, which can be easily 

 demonstrated if the expenses are exactly estimated, and if it be 

 taken into account that in the case of the winch the cost of 

 an attendant and one or two horses is incurred. Even the best 

 winches do not yield their impelling power as regularly as is 

 required for the driving of separators. Steam-engines are most 

 suitable for dairies in which separators are worked by power, for 

 the reason that both motor power and heat are already there 



