138 BUTTER-MAKING. 
is an example of this latter class. These two methods of regu- 
lating the thickness and amount of cream are the most common. 
It cannot be done while the machine is in motion. By some 
this is considered a drawback. 
Other separators have a device whereby the amount of 
cream can be regulated while the machine is in motion. For 
instance, on the improved Danish Weston, there is a screw 
attached to the skim-milk discharge-tube, by turning which 
the end or point of the tube can be made to be closer or farther 
away from the center, thus regulating the relative amount 
of cream and skimmed milk, and the thickness of the cream. 
2. Rate of Inflow.—The rate of inflow of milk to the sepa- 
rator has a large influence on the relative amount of cream 
and skimmed milk. The greater the inflow to the separator, 
the more and thinner cream will be obtained, and with a dimin- 
ished inflow the less and thicker cream is obtained. This is 
due to the fact that at a given velocity of the machine the 
skim-milk discharge remains practically constant. So, if 
more milk is turned on, the only place where the discharge 
can increase is through the cream outlet; and if the inlet is 
diminished, the cream will diminish until a certain time, when 
the amount of milk, which runs into the machine, equals the 
amount discharged through the skim-milk outlet, and then 
there will be little or no cream. This is aptly illustrated 
by Wing: “If the milk is turned into the bowl at such a 
rate that .8 escapes through the skim-milk outlet, we shall 
have .8 skim-milk and .2 cream. If, now, we reduce the rate 
of inflow by .1, we shall get just as much skimmed milk as 
before, but only half as much cream; or, if the inflow is increased 
-1, we shall get the same amount of skimmed milk and one 
and a half times as much cream.” The completeness of sepa- 
ration will be the same so long as the separator is run within 
the range of its capacity. 
3. Speed.—The speed of the separator influences the rela- 
tive amount of the cream and skimmed milk only in so far 
as an increase in the speed of the bowl increases the capacity 
