86 TESTIMONY OF CHARLES F. CHANDLER. 



the surface it generally either attracts or is attracted by that sur- 

 face ; as a consequence when the lactometer is dropped into the 

 milk, the milk does not rise against the lactometer on a perfect 

 level ; but, on the contrary, climbs up the side of the lactometer a 

 certain distance, and covers a portion of the lactometer ; the con- 

 sequence is that when you look at the lactometer you are in doubt 

 as to exactly where the surface of the liquid cuts the scale on the 

 lactometer ; in some liquids the contrary takes place ; in the case of 

 mercury the liquid does not climb up the glass, but on the contrary, 

 there is a light depression, so that it would have the appearance of 

 my diagram when inverted ; that is called meniscus, and it makes a 

 difference in the case of milk of two or three degrees, whether one 

 reads what is actually visible ; it is all the same if they read it al- 

 ways in the same way. 



Q. Have investigators in natural science a personal rule of read- 

 ing scales of this kind ? A. It depends altogether on circumstan- 

 ces ; if the instrument is graduated so as to be read above the men- 

 iscus, that is the proper way to read it ; if the instrument is 

 graduated to be read on a line with the surface of the liquid independ- 

 ent of the meniscus, then that is a proper way to read it; the 

 lactometer is graduated to be read at the top of the meniscus ; I 

 read at the top of the meniscus ; Dr. Barker differed from me by 

 reading it below the meniscus. 



Q. How do you know ? A. He said so. 



Q. Now, Dr. Chandler, in examining a sample of commercial 

 milk yesterday before the Court and the jury, or cream perhaps it 

 was, or both, there were used four lactometers and the experiment 

 of the fluid in one instance was found far below 100 and in another 

 instance it was from 14 to 16 or 17 above ; I ask you have you tested 

 those four lactometers upon the scale and mark of Board of Health 

 100, so that in these several experiments of variation of from two 

 to three degrees at those very high and very low degrees upon the 

 scale were shown? 



(Objected to ; objection overruled ; exception.) 



A. I have tested them ; they were tested under my direction, 

 originally, and agreed exactly at the 100 point and approximately at 

 other points, sufficiently for all practical purposes as a test for 

 watered milk ; desirous to know how great a deviation there might 



