620 TESTING #OR 



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creanl to "oil off." This precaution is especially necessary with thin 

 cream. 



Cream Test Bottles. Use standard 50 per cent 9-gram short- 

 neck, or standard 50 per cent 9-gram long-neck, or standard 50 per 

 cent 18-gram long-neck cream test bottles. The divisions on each of 

 the three standard cream test bottles represent .5 per cent, 1 per cent 

 and 5 per cent. The 5 per cent divisions bear a figure to the left of 

 the graduation. 



Cream Test Balances. Only high-class balances which are in 

 satisfactory operating condition should be used. The reliability of 

 the cream test balance depends in the first place on its sensitiveness 

 and capacity. Experiments conducted with different types of cream 

 testing scales by Hunziker, Spitzer and Ogle 1 showed the following 

 results and conclusions : 



1. Results of tests of 4623 cream samples made in commercial 

 creameries show that where the one-bottle balances were used, 96.43 

 per cent of the tests checked with the retests within .5 per cent, while 

 the best performance of the twelve-bottle balance yielded only 80.43 

 per cent of tests that checked with the retests. 



2. Balances with a sensibility reciprocal of .01 to .03 grams 

 produced tests, 98.2 per cent of which checked with the retests, and 

 the average variation between duplicate tests was .119 per cent. 



3. Balances with a sensibility reciprocal of .1 gram yielded only 

 36.1 per cent of tests which checked with the retests, and the average 

 variation between duplicate tests was .993 per cent. 



4. The condition, care and manipulation of the cream test bal- 

 ance greatly influence its sensitiveness, reliability and length of use- 

 fulness. 



5. The general adoption of standard cream test balances with 

 a sensibility reciprocal of thirty milligrams would materially augment 

 the reliability of cream tests. 



6. Preference should be given to small capacity balances. 



7. Balances, with a graduated beam which carries a traveling 

 poise are less reliable than those with a beam of equal arms, balanc- 

 ing in the center and requiring the use of separate weights. 



8. Balances of simple principle and construction are generally 

 superior under average commercial conditions, retain their sensi- 

 bility reciprocal longer and are more durable than balances of more 

 complex principle and construction. 



1 Hunziker, Spitzer and Ogle, Cream Testing Scales, Purdue Bulletin 189, 

 1916. 



