Estimation of Solids not Fat. 65 



found to represent about the amount occupied by 

 the curved surfaces in the neck of the bottle, 

 due to the capillary attraction between the fat and 

 the glass. 



Cleaning the glassware. — Good results cannot be 

 secured unless the glassware is kept clean and 

 bright. This can easily be done with yevy little 

 trouble. As soon as the bottles are read, and while 

 they are still hot, the contents should be emptied 

 out. The hot acid and water will carry out with 

 it the larger part of the fat in the neck of the 

 bottle. The emptied bottle should then be rinsed 

 once in warm water and once in hot water containing 

 some alkali, either washing soda or any of the va- 

 rious washing powders, and then rinsed with either 

 warm or cold water until they are perfectly clean. 

 With these precautions no difficulty w^ill be expe- 

 rienced in keeping the bottles clean and bright. 



By the use of the lactometer in connection with 

 the percentage of fat, a close approximation to the 

 percentage of total solids, or solids not fat, may be 

 made. Numerous formulge for this purpose have 

 been devised. Their application is explained and il- 

 lustrated in Part A of the Appendix. 



