152 Testing Milk and Its Products. 



tity of milk secured in the tube will always stand in the 

 ratio to that of the milk in the pail, of (J) 2 to 8 2 , 1 

 that is, very nearly 1 to 256; no matter how much or 

 how little milk there is in the pail, the sample will 

 represent T J-g- part of the milk. For composite sampling 

 of the milk of single cows, this proportion will prove 

 about right; if more milk is wanted for a sub-sample, 

 dip twice, or pour the milk to be sampled into a can of 

 smaller diameter. If the mixed milk from a number of 

 cows is to be sampled, a wider sampling can is used. By 

 adjusting the diameters of the tube and the can, any de- 

 sired proportion of milk can be obtained in the sample. 



For factory sampling, with a weighing can, 26 inches 

 in diameter, a tube three-quarters of an inch in diameter 

 will be found of proper dimensions. 



In using any one of these tubes, the size of the sample 

 is regulated by the amount of milk in the sampling can, 

 as the milk always rises to the same height in the tube 

 as iii the can. In all cases cylindrical sampling cans 

 must be used. 



182. The sampling tube will furnish a correct sample 

 of the milk in the can, even if this has been left stand- 

 ing for some time; it is better, however, to take out the 

 sample soon after the milk has been poured into the can, 

 as the possible error of cream adhering to the side of the 

 sampling tube is then avoided. 



183. The accuracy of the sampling of milk by means 

 of the Scovell tube was proved beyond dispute in the 



i The contents of a cylinder are represented by the formula 7Tr 2 h, r 

 being the radius of the cylinder, and h its height. The relation between 

 two cylinders of the same height, the radii of which are R and r, is there- 

 fore as 7TR 2 h to 7Tr 2 h, or as R 2 to r 2 . 



