FROM THE PRACTICAL VIEWPOINT 



filled, the milk of course falls from the inlet pipe 

 at the top to the bottom of the tank, and afterward 

 onto the surface of the body of milk in the tank as 

 it fills up to the level of the outlet pipe. In conse- 

 quence there is considerable agitation of the liquid 

 and currents are created. This may cause the last 

 milk which enters the tank to be the first to be 

 discharged, and our holding time becomes a mat- 

 ter of uncertainty. If, however, the lower tank is 

 the first one filled, we are then sure that all the 

 milk in this tank is held for at least the time re- 

 quired for the other tanks to fill. 



This method of filling may be effected in either 

 of two ways: First, a pipe may extend along the 

 top of the tanks in such a way that by opening the 

 proper valves the milk may be directed into either 

 tank at will. Second, the pipe may be arranged 

 at the bottom of the series in such a way that 

 either tank may be filled, if the proper valves are 

 opened and closed. Both arrangements of pipes 

 are shown in Fig. 24. 



It has been found by tests that this form of 



holder never holds the milk for a period of time 



as long as that which is required for them to be 



filled. Depending upon the form of the tanks and 



119 



