144 SCIENCE AND PRACTICE OF DAIRYING. 



separators, the author obtained better results if he substituted, in the 

 above formula, for the square root of (m), simply (m). The above formula 

 was well suited for the three separators, which were almost exclusively 

 used up till 1888. As to whether it also suits the Alpha, the Balance, 

 and the Victoria separators in their present form, the author has not yet 

 been able to make investigations. 



In order always to obtain satisfactory results, the following points have 

 to be carefully observed in practice : 



(1) That the drum should always revolve at the prescribed rate; to 

 permit it to revolve more quickly may be dangerous (see 60), and if it 

 does not revolve sufficiently quickly there may be a considerable loss. 



(2) That the milk to be creamed every day should be of suitable 

 quantity, and should enter at as uniform a rate as is possible per hour. 



(3) That the milk during the whole period of creaming should possess 

 the proper temperature. 



(4) That the separator should always be in good order, and should be 

 carefully lubricated with good oil. 



71. The Supervision of the Revolving Rate of the Drum. For- 

 merly the rate of revolution of the drum was shown by an indicator, 

 which was either in permanent connection with the well of the 

 drum, or was pressed against the head of the well from time to 

 time, in order to show if the drum were revolving at the prescribed 

 rate. This indicator showed how many revolutions per minute the 

 drum made during the time of observation. For ordinary use, how- 

 ever, it is unnecessary always to know the exact number of revolu- 

 tions per minute. It is sufficient to know whether the drum is 

 revolving at the prescribed speed, or whether the speed is increasing 

 or diminishing. This is shown by the new indicator, devised by 

 Dr. O. Brown, of Berlin, which may be directly or indirectly placed 

 in all separators in a very simple way. As the success of creaming 

 is influenced, to a large extent, by the rate at which the separator 

 drum revolves, work should never be carried on without an indi- 

 cator. 



In the case of hand-separators, it is often sufficient to regard the 

 revolution of the handle as an indication of the prescribed number 

 of revolutions per minute. This may be effected without using an 

 indicator by utilizing the swing of a swinging pendulum, the 

 number of swings of which per minute correspond exactly with the 

 desired number of the revolutions of the handle. No doubt it is 

 certain, in the case of hand-separators, that the drum assumes the 



