92 PROCEEDINGS OF THE AMERICAN ACADEMY 



Calculated. Found. 



Carbon Qo 60 56.3910 " 49.85 



Hydrogen Hu 11 10.3383 10.72 



Chlorine CI 35.4 33.2707 32.47 



100. 93.04 



2. — 0.1657 gramme of chloride of amyl gave 0.3314 of carbonic 

 acid and 0.1608 of water. 



IV. Experiments with Oxide of Copper, as absorbent of Chlorine in 

 the analysis of substances rich in Hydrogen. 



• 



In these experiments, for the reason previously stated, the oxide of 



copper could only be placed in the anterior end of the combustion tube, 

 where it might be maintained at a tolerably low temperature. After 

 two or three experiments, — which were but partially successful, — it 

 became apparent that the range of temperature Vithin which oxide of 

 copper could be made serviceable to absorb the chlorine was probably 

 rather limited. 



It was observed, for example, that at 150° to 160° even brown oxide 

 of copper, which had been but gently ignited, would fail to absorb 

 nearly all of the chlorine, and consequently the determination of the 

 carbon, -and sometimes that of the hydrogen, would be in excess. In 

 one experiment, in which the oxide of copper was kept at about 153° C, 

 its appearance had suffered no change, and it was found to contain only 

 8.29 per cent of chlorine, or only about one quarter of the theoretical 

 quantity. When a sufficiently high temperature is employed, on the 

 contrary, the posterior end of the column of oxide of copper and asbes- 

 tos has the appearance of being entirely changed into yellow chloride 

 of copper, the rest of the column remainingj for the most part, of its 

 original dark color. 



In another experiment, with the oxide of copper kept at a tempera- 

 ture of about 160°, only about fourteen per cent of chlorine was obtained. 



In both of these experiments the carbon determination was consid- 

 erably in excess, and in one of them the hydrogen also. The oxide of 

 copper employed had been strongly ignited. 



