620 



The result of several comparisons of this method with that of drying 

 in a glass with frequent stirring showed that practically the same 

 results were obtained by the pumice-stone method in 2 hours as with 

 the other in 5 hours. 



To determine whether the water contained in a sample of butter is 

 entirely expelled by heating with pumice stone for 2 hours, clear, fil- 

 tered, and thoroughly dried butter fat was mixed with whey containing 

 3 per cent of common salt, the water content of which had been care- 

 fully determined. Samples of this mixture containing about 11 grams of 

 butter fat each were dried with and without the addition of pumice 

 stone. The sample to which pumice stone had been added was dried 

 to a constant weight and had given up the calculated amount of water 

 at the end of 2 hours, while that dried by itself required 6 hours. 



