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CALIFORNIA ACADEMY OF SCIENCES. 



chloroform, that is: (3) the least possible volume of solu- 

 tion, because, the more solution the more chloroform must 

 be given to obtain drops of sufficient quantity for a good 

 observation of color. 



The following table will record the results of this assay 

 in a better shape, + expressing increase, — decrease of color, 

 ? doubtful. 



It will be observed that the one dangerous calculation in 

 this titration was the fourth of No. 1, which brought me on 

 a not perfect observation too near to the result. I choose 

 intentionally this example for pointing out the danger of 

 adding too much from the burette on the observation of the 

 first fractional titration, when the second cup contains still 

 colorless liquid and offers no chance for comparison of 

 colors. The increase of color becomes easily fallacious 



