Relative Amount Skimmed Milk and Cream 1838 
slighter degree. Small-sized fat globules, viscosity of 
the milk, and coagulation of part of the casein by 
incipient fermentations, all tend to make separation 
more difficult; but in a majority of cases, unless the 
milk is so sour as to be coagulated, it may be completely 
creamed with a centrifugal separator, but will require 
a slower feeding (a reduction of 10 to 15 per cent will 
usually suffice), and a higher speed of the bowl, or both. 
Conditions affecting the relative amount of skimmed 
milk and cream.—The relative amount of skimmed 
milk and. cream is affected by the rate of inflow, 
by the speed of the bowl, by various special con- 
trivances upon the machines themselves, and to a 
slight extent by the temperature of the milk. In 
the ordinary machine the size of the skimmed milk 
outlet is fixed, and therefore at a given velocity the 
outlet will discharge a nearly uniform quantity of 
fluid. If then, the milk is turned into the bowl at 
such a rate that .8 of it escapes through the skimmed 
milk outlet, we shall have .8 skimmed milk and 
.2 eream. If now we reduce the rate of inflow 
by .1, we shall get just as much skimmed milk as 
before, but only one-half as much cream; or if the 
inflow is increased by .1, we shall get the same 
amount of skimmed milk and once and a half as 
much cream. If under the first conditions all of the 
fat was gathered into the cream, we shall have just 
as complete a separation as before, but shall simply 
get a cream containing a greater or less percentage 
of fat, provided that the increase of inflow has not 
increased the total amount above the capacity of the 
