A MOISTURE TESTER FOR GRAIN. 



SPECIFICATIONS FOR THERMOMETERS. 



In order to secure a high-class thermometer at a minimum cost it 

 has been found advisable to adopt a thermometer which can be used 

 for general laboratory work. The thermometer should be graduated 

 m whole degrees from 0° to 200° C, with the graduations etched on a 

 stem having a white background. The diameter of the stem of the 

 thermometer should be nine thirty-seconds of an inch, so that it Mall 

 fit properly in the No. 5, one-hole, rubber stopper. The length of 

 the mercury bulb should be approximately three-fourths of an inch — 

 not greater than thirteen-sixteenths nor less than eleven-sixteenths 

 of an inch. The total length of the thermometer should not exceed 

 13 inches. 



The manufacturers should be required to furnish certificates of 

 correction with all thermometers showing errors in calibration and 

 graduation exceeding one-half of a degree at 175° and 190° C. 



GRADUATED MEASURING CYLINDERS. 



The small graduated cylinders for measuring the moisture should 

 have a capacity of at least 25 cubic centimeters. They should be 



^ ,-..---^- carefully graduated in fifths, so that the readings 



" ' " can readily be made in tenths. When 100 grams 

 are used for the test, the number of cubic centi- 

 meters of water in the graduate corre- 

 sponds to the percentage of moisture 

 originally contained in the sample. If 

 only 50 grams are used, as is necessary 

 with some substances, the number of 

 cubic centimeters of water in the grad- 

 uate is equivalent to one-half of the 

 moisture percentage. 



In making moisture determinations a 

 small quantity of oil — usually less than 

 one-half of a cubic centimeter — is carried 

 over into the measuring cylinder and 

 collects on the surface of the water, so 

 that the readings should be made at the 

 bottom of the meniscus between the oil 

 and the water, as shown in figure 3. 

 Should the oil and the water not separate 

 readily, the graduated cylinder should be 

 whirled by rolling quickly between the 

 two hands. 



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3.i... 



Fig. 3.— Graduated meas- 

 uring cylinder, showing 

 20 per cent of moisture. 



Fig. 4.— Swab 

 or test-tube 



After each test the cylinders must be cleaner. 

 cleaned and dried, which can best be done with a swab or test-tube 

 cleaner having a small sponge attached to one end, as sho^oi in figure 4. 



[Cir. 72] 



