MARKET PREPARATION, TRANSPORTATION, STORAGE 275 



TABLE I 

 All corrections given below are to be subtracted from the Brix reading: 



TEMPERATURE (DEGREES "c") CORRECTION 



.46 



5 .40 



10 .31 



11 .27 



12 .23 



13 .20 



14 .16 



15 .13 



16 .08 



17 .03 



All corrections given below are to be added to the Brix reading: 



18 .03 



19 .08 



20 .16 



21 .23 



22 ,30 



23 .36 



24 .42 



25 .48 



EXERCISE V. The principle of refrigeration. 



Materials. Two glass beakers, small bottle of ether, 25 c.c. of water, 

 1-200 c.c. flask. 



Caution. Do not allow a flame of any sort in the vicinity of ether! 

 It is highly explosive! 



Procedure. 1 Pour the water into the flask and with this held 

 slanting in the hand, pour ether over the outside into the other beaker. 

 Then pour the ether from this beaker again over the flask into the first 

 beaker. Continue the process until the water in the flask is frozen. 



Ether evaporates very readily. When it does so it absorbs heat 

 from the flask. This causes the water to freeze. 



The same process takes place in a refrigerator plant except that in 

 this case ammonia which is very much cheaper than ether is utilized. 

 The ammonia extracts heat from a solution of salt and water and this 

 cold brine is then circulated through pipes which are located in the 

 cold storage-rooms. 



1 If the quantity of material available is small or if the room is close, this 

 had better be performed as an instructor's experiment. 



