WEIGHING OUT SAMPLES 



319 



Another reason why it is essential to weigh cream is the 

 presence in the cream of larger or smaller quantities of gas. 

 Naturally any cream which has been poured or stirred until it 

 contains a considerable amount of air or other* gas will occupy 

 more volume for its weight than it would if it had not been so 

 treated. 



The kind of scales to be recommended will vary with the 

 volume of work to be done. The finely adjusted Torsion balance 

 designed to accommodate two to four bottles at a time is exceed- 

 ingly sensitive and valuable when high-class work is to be done. 



Weighing Out Samples. — It is sometimes necessary to warm 

 the bottle of cream to make the cream flow more readily. A 



Fig. 109. — An inexpensive tester, yet one not to recommend for general farm use. 

 The samples cool too quickly in this and if a bottle were to break, the acid would be liable 

 Jo do injury. 



quantity of cream may then be drawn into the pipette and 

 allowed to flow into the test bottle on the scale, care being taken 

 that a quantity be added sufficient only to bring about an exact 

 balance. In doing this, care should also be taken that no drop of 

 cream falls upon the outside of the bottle or upon the platform 

 of the scale. When the sample has been weighed out it may 

 be set aside to be tested at any future time. The water only can 

 evaporate. It is best, however, to run out the samples while they 

 are still fresh. 



