226 TESTIMONY OF CHABLES A. DOBEMUS. 



but if you will give me the book I can immediately refer to it ; he 

 speaks about looking at hydrometers when you buy them to see 

 whether they are correct or not ; I would like to quote from page 

 14 to the middle of the page : " In buying a hydrometer it is neces- 

 sary to see that the stem shall be as cylindrical as possible, and that 

 the divisions on the scale shall not equal each other, but be inversely 

 proportional to the specific gravities which are given by the 

 bounding lines of division ; that applies to all hydrometers." 



Q. Have you made any practical tests with milk, comparing it 

 after being transported or after some delay in the time of its 

 milking ? A. I have, sir. 



Q. What has been the result of those tests? A. It always 

 changes in specific gravity. 



Q. Can you assign any reason for it, or give any reason for it ? 

 A. I cannot positively assign any reason ; I believe the reason given 

 by authors is that some change takes place in the caseine of the 

 milk ; the fact, however, remains that the change does take place ; 

 that I have verified by my own experiments. 



Q. Now what is the effect of mixing an equal quantity of milk 

 of high and low specific gravity, one being rich in cream ? A. I 

 took three samples of milk bought ; one stood at 110 and the second 

 and the third which purported to be First avenue cream, stood at 92 ; 

 it was simply rich milk ; I took equal parts of the sample No. 1 and 

 sample No. 3, and I mixed them ; they were equal quantities of 

 milk at 110 and milk at 92 ; by calculation the resulting specific 

 gravity would have been 101 ; by actual experiment its specific grav- 

 ity was only 98, three degrees out of the way ; I then took sample 

 No. 2, which stood at 110, and mixed it in equal quantities with the 

 milk at 92, and the resulting specific gravity was in that case, not a 

 calculated specific gravity, but 99, two degrees out of the way, show- 

 ing, may it please your Honor, that when you mix equal quantities 

 of rich and fair milk that you cannot calculate the specific gravity, 

 because both of these samples which stood at 110 were mixed with 

 equal quantities of milk at 92 and they did not agree in getting a 

 resulting specific gravity, but one differed from the other and they 

 both differed by two and three degrees from the specific gravity by 

 average ; I made another sample which I also wish to refer to, for 

 fear the objection might arise in regard to milk being purchased 



