38 QUESTIONS AND ANSWERS 



3. Bottles with capacity of 9 grams of cream 

 and 9 c. c. of acid and a scale showing the percent- 

 age direct as high as 50 per cent. 



4. Bottles with scales showing the percentage 

 direct, to 50 per cent for 9-gram samples, and 

 with bodies large enough so the cream may be 

 diluted with water before adding the acid. 



What advantages has a g-gram cream bottle 

 over other forms when the graduations on it 

 show the percentage direct and its body holds 

 about 50 c. c? 



1. Accuracy is increased, because a neck of 

 smaller diameter and a finer scale may be used. 



2. In reading the percentage direct any error 

 is not doubled as occurs with the ordinary bottle 

 when the sample is divided and the observed read- 

 ing is doubled. 



3. The smaller diameter of the neck reduces 

 the error due to the difficulty of making proper 

 allowance for the space occupied by the meniscus. 



4. The size of the body allows the addition of 

 9 c. c. of water before adding the usual amount 

 of acid, thus diluting the cream and preventing the 

 acid from attacking the fat, as often occurs when 

 equal volumes of rich cream and acid are mixed. 



5. Richer cream may be tested, as the bottle 

 may be graduated to give readings of 50 per cent. 



How does the graduated portion of the neck in 

 cream test bottles vary? 

 I. It varies in capacity, some bottles being 

 graduated from zero to 50 per cent and others from 

 zero to 30 per cent, etc. 



