10 



BULLETIN" 744, U. S. DEPARTMENT OF AGRICULTURE. 



cents a hundredweight, would be $72. Frequently ice costs more than 

 the price named, which would add to the saving effected by an in- 

 sulated tank. While few dairymen would waste so large a quantity 

 of ice, the result indicates the economy of using a covered, insulated 

 tank. 



Four other tests were conducted with the same tanks under best 

 service conditions. All tanks were covered and sheltered. The gal- 

 vanized-iron, concrete, and wooden tanks each contained 1,000 pounds 



ioa 



o 



8A.M. 



Fig. 7.- 



2 -3 



/0:00A.M. 



a 



4-OOPM. 



4 S ~6 7 



/Soo/voorv ZooPM. 



TIM£— HOUK S . 



-Rise in temperature of water during 9 hours in 4 types of cooling tanks 

 All tanks uncovered and exposed to direct rays of sun. 



/<? 



of water at 51° F., a 100-pound block of ice, and a 10-gallon can of 

 warm milk; the cork-insulated tank contained the same quantity of 

 water and ice and two 10-gallons cans of milk. In each case the block 

 of ice was placed close to the can in order that the milk might receive 

 its immediate cooling effect. The water in the tank was slightly 

 stirred each hour, after which the temperature reading Avas taken. 

 The milk was not stirred during any of the tests; the results of the 

 tests are shown in figure 11. 



