CHAPTER V. 



Discussing Comparative Reading of Cream Test 

 Bottles. 



Note. — For convenience in illustrating the per 

 cent on the graduation is numbered from top down, 

 instead of the usual way, from the bottom up. 



78. Basis of comparison. Assuming that the read- 

 ing of the actual fat column of any cream test bottle 

 is .2 per cent lower than the actual per cent of fat 

 in cream, due to .2 per cent of fat remaining in the 

 bulb of the bottle ; we will take the method of read- 

 ing the milk test bottle as a standard for compari- 

 son. The average creameryman reads the tests at 

 about 130° F. The meniscus is about .2 per cent on 

 the reading of the test, which is equal to the .2 per 

 cent of fat left in the bulb of the test bottle. 



79. Comparing the Reading of 30 per cent, 9 in, 

 cream bottle with a milk test bottle. Fig. I. The 

 average depth of the meniscus of the 30 per cent 9 

 in. cream test bottle, Fig. II, is between .4 — .5 per 

 cent. Reading this bottle to the extreme top of the 

 fat column, the reading will be from .2 to .3 per 

 cent too high. The curvature of the bottom of the 

 fat column is greater than the curvature of the fat 

 column in the milk test bottle. Fig. I. 



By reading the fat column in the cream test bot- 

 tle, Fig. II., from the extreme bottom to the extreme 

 top, the reading will be about .4 per cent too high. 

 According to the variation in the eveness of the bot- 



299 



