14 



A MOISTURE TESTER FOR GRAIN. 



satisfactory. Balances similar to the two types shown in figure 13, 

 which have a special scoop for emptying the weighed samples into the 

 distillation flasks, will meet all requirements. Such balances are 

 likewise much less expensive, less likely to get out of order, and more 

 easily operated than the delicate analytical balances commonly used 

 in chemical laboratories. 



Fig. 13.— Balances with a set of polished brass weights, 400 grams to 5 grams. Left, torsion balance; right, 



trip scale with agate bearings. 



Wliatever the type of balance used, it should rest on a firm support, 

 preferably a heavy shelf securely fastened to a solid wall of the build- 

 ing, which will greatly facilitate the keeping of the scale in balance, 

 which is absolutely essential for reliable work. 



SPECIAL POINTS FOR CONSIDERATION. 



(1) The moisture tester should be installed in a place where it will 

 not be exposed to strong air currents. 



(2) The tester can be equipped for burning alcohol or gasoline, but 

 gas is to be preferred whenever available. 



(3) The wire gauze with asbestos center should be kept in good con- 

 dition so that the flame will not plav directly upon the bottom of the 

 flask. 



(4) The bottom of the flask should be not less than three-eighths 

 of an inch above the wire gauze. 



(5) See that the column of mercury in the thermometer is contin- 

 uous; if broken it should be shaken down. 



(6) Adjust the thermometers in the rubber stoppers so that the 

 bulbs of the thermometers will be approximately four-fifths im- 

 mersed in the oil. 



(7) Keep a good supply of cold water running through the con- 

 denser tank. 



(8) Adjust the flame so that about twenty minutes are required to 

 reach the prescribed temperature. 



[Cir. 72] 



