622 TESTING FOR BUTTER? AT 



greater than one-half grain or approximately 30 milligrams, when 

 the scale is loaded to capacity." 



Manipulation of Balance. .1. Level the balance each time be- 

 fore using. 



2. Adjust or balance the instrument immediately before weigh- 

 ing and make sure that its beam swings freely and does not "stick." 



3. Protect the balance from air currents. If resting on an open 

 bench have the nearest doors and windows closed. The setting of 

 the balance in a box large enough for convenient operation and with 

 the near side open is recommended. 



4. Use accurate weights only and be sure that they are clean. 



5. Don't release the balance with a jerk so that the pans strike 

 the rest ; release them easily and slowly and handle them gently when 

 they are moved. Careless and rough handling may damage spring 

 bands and dull knife edges. 



6. Don't try to use the balance when out of repair. 



7. Use painstaking care and reasonable judgment in all opera- 

 tions. 



SPECIFICATIONS FOR STANDARD NINE AND 

 EIGHTEEN GRAM WEIGHTS 



1. Weights shall be made of brass or aluminum. 



2. Weights shall have smooth surfaces and no sharp points or 

 corners. 



3. Weights shall not be covered with a soft or thick coat of 

 paint or varnish. 



4. All weights shall be clearly marked with their nominal value 

 i. e. 9 for nine gram weights and 18 for eighteen gram weights. 



5. The tolerance shall be forty milligrams for nine gram 

 weights and fifty milligrams for eighteen gram weights. 



Weighing the Cream Into the Test Bottle. The cream must 

 be weighed into the test bottle, not measured. This is necessary in 

 order to secure the correct amount by weight. Cream varies in 

 weight with its richness and its mechanical condition, and no one 

 measure will hold the correct amount of cream of varying richness. 

 The correct amount of cream by weight is 9 grams or 18 grams, 

 respectively. 



Set the cream test bottles on the scales and balance the scales 

 accurately. The cream is most readily transferred into the test 



