AGRICULTURAL CHEMISTRY 



The small balance used for weighing materials in these 

 experiments is shown in Fig. 5. In case 5 grams of a 

 material are to be weighed, prepare counterpoised papers, 

 about 3 by 4 inches in size ; that 

 is, two pieces of paper of exactly 

 the same size to be placed on op- 

 posite sides of the balance. If 

 they do not weigh alike, remove 

 small pieces of paper from the 

 heavier pan, until the needle 

 moves nearly as many divisions 

 on one side of the scale as on the 

 other. Then place, with the for- 

 ceps, the 5-gram weight on the 

 Fig. 5. Balance. right-hand pan of the balance. 



Do not handle the weights with the ringers. By means of 

 the scoop or spoon provided for the purpose, add to the 

 paper in the left-hand pan of the balance, enough of the 

 material that is to be weighed to counterpoise the 5-gram 

 weight. If any of the substance has been spilled it should 

 be cleaned up at once. The weight should be replaced in 

 the weight box and the forceps returned to their proper place. 

 If the weights are lost, a charge is made to cover the ex- 

 pense of their replacement. No substance except a piece 

 of metal, as copper or lead, should ever be placed in direct 

 contact with the balance pan. Liquids are never weighed, 

 but always measured. Too much care and neatness can- 

 not be exercised in weighing. 



28. measuring Liquids. For purposes of measuring, 

 cylinders or graduates are employed (Fig. 6). A large 



