90 



is on the plan of the Smith cooler, being made with corruga- 

 tions. The latter has small concentric rings, which tend to 

 delay the milk in its downward course. The upper tank is 

 a good deal smaller in proportion than the original McPher- 

 son. 



In order to get the full bene- 

 fit of the ice it is necessary to 

 have some kind of device for 

 stirring the ice or keeping the 

 cooling water in motion. Mr. 

 Brown, in his cream cooler, 

 Fig. 90J, provides a hand pump. 

 The cream runs in at a and out 

 at the bent tube, which may be 

 lowered to empty the can. In 

 handling milk or cream, pas- 

 teurized or unpasteurized, for 

 the market, too much stress can 

 not be laid on a quick and thor- 

 ough cooling, the nearer 34 

 the better. Where cold water 

 i s plentiful 

 coolers on the 

 Lawrence 

 principle, 



Fig. 90%. such as the 



"Star," Fig. 91, or The Reid (see Fig. 68), 

 and others are among the best of all coolers 

 and aerators combined, and if water is 

 scarce, the best system is to have a water 

 tank filled with crushed ice and circulate 

 that in the cooler. 



Fig. 91. 



AERATION. 



Meanwhile, if the combined coolers and aerators are not 

 available, cooling by aeration only is better than nothing, 

 although perhaps this may hardly be true when speaking 

 about preparing milk for city shipment. 



The simplest aeration is by lifting a dipper of milk 



