eas 
A ee 
DF Ie eee 
New YorK AGRICULTURAL EXPERIMENT STATION. 157 
divisions of micrometer scale, would pass at one and one-third 
inches per hour, is as follows: 


Divisions of mi- 
crometer. ... 
Number of diam- ‘ 
OBULOEN SM c wea | e 100. 
eee | 
5 | Mel eee 2. | 2.6.) 8. | 8,5) Seni Be Ne, 
25. | Dy OLAS Tae COM a 









66. 50. | 40. an 28. 

The actual diameters in fractions of an inch, represented by 
these several divisions of the micrometer scale, are as follows : 


Divisions of Fractions of Divisions of Fractions of 
micrometer scale. one inch. micrometer scale, one inch. 
5 .0000473 3.5 .00038311 
1.0 .0000946 4.0 .00038784 
EVD .0001419 4.5 .0004257 
2.0 .0001892 5.0 .00047380 
2:5 .0002365 5.5 .0005203 
3.0 .0002838 6.0 . 0005676 

Now, since the resistance which these globules meet with in 
rising increases with the square of their diameter, while their 
ascensional force or buoyancy increases as their volumes, or as 
the cubes of their diameters, we may readily conclude that the 
larger globules are those first to reach the surface, and that if 
any fail to do so, it must be the smaller globules which the 
microscope should show in the skim-milk. 
By means of the separator the centrifugal force increases the 
difference between the weight of the milk globule and the milk 
serum in which it is suspended, and since this difference thus 
increased will depend upon the size of the globules, it follows that 
the skim-milk from the separator should also show that the 
smaller globules only were left behind in this operation; and such . 
we find to be the facts whether the skim-milk is obtained by 
setting or by the centrifugal. 
Upon December 29, 1891, the American Holderness cow 
Nellie 6th, one month in milk, gave milk which by the Cooley 
system of setting and by the Baby separator yielded skim-milk of 
the following composition as determined by microscopic examina- 
——————— ty 
