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PROCEEDINGS OF THE AMERICAN ACADEMY 



Occluded Gas ix Clpric Oxide. — First Series. 



The series was discontinued because a new method had been de- 

 vised which was much less tedious and much more direct in its exe- 

 cution. According to the new method, the cupric oxide to be analyzed 

 was introduced into a tube shaped in the manner shown in Figure 2. 



Fig. 2. 



After the bulbs had been nearly filled with thoroughly boiled warm 

 water, the open mouth of the tube was connected with an air pump to 

 remove any mechanically adhering air. The water was usually allowed 

 to boil for several minutes under the reduced pressure. The air was 

 then readmitted, and the tube was entirely filled with pure boiled 

 water, being placed perpendicularly for the purpose. When the tube 

 had been returned to its usual position, acid was added through a fine 



