OF ARTS AND SCIENCES : JANUARY 31, 1866. 91 



body, containing as it does eighty-nine per cent of chlorine, and only 

 eighty-five hundredths of one per cent of hydrogen, must be considered 

 as an extreme case, and does not prove the process a good one for 

 other classes of substances. 



The next step, therefore, was to determine whether the process would 

 be equally efficient in the analysis of substances rich in hydrogen, the 

 combustion of which would give rise to the formation of a large quan- 

 tity of hydrochloric acid. The substance selected for analysis, to settle 

 this question, was chloride of amyl. 



III. Experiments with Oxide of Zinc, as an absorbent of Chlorine in 

 the analysis of substances rich in Hydrogen. 



In these experiments, the oxide of zinc was employed in the same 

 manner as above described for the analysis of chloroform. The chloride 

 of amyl, which was the subject of analysis, was prepared in the usual 

 manner. Its boiling-point was 102°, 8 corrected. 



The following results of two analyses with oxide of zinc indicate 

 that this oxide combined with and retained some of the carbonic acid. 

 This result was not anticipated, as in the analysis of chloroform the 

 determination of carbon was uniformly slightly in excess.* 



The Results of these two analyses are as follows : — 



1. — 0.1922 gramme of chloride of amyl gave 0.3513 of carbonic 

 acid, 0.1854 of water, and 0.2528 of chloride of silver. 



* Since the above was written, I have observed, on reviewing my notes, — not 

 only of experiments with oxide of zinc, but also with oxide of copper, — that in ev- 

 ery analysis in which I made note of carbonization, or blackening of the asbestos in 

 the combustion tube, — which may sometimes occur from too rapid distillation of 

 the substance, or, what amounts to the same thing, a deficiency in the supply of 

 oxygen, — there was a loss in the determination of the carbon, and generally, also, 

 in that of the chlorine ; while the hydrogen would agree pretty nearly with the theo- 

 retical quantity. I am, therefore, at the present writing, inclined to suspect that 

 the carbonization may have had some connection with the deficiency in the carhon 

 determinations in these instances, although the blackening would readily and com- 

 pletely disappear so soon as a sufficiency of oxygen was supplied. This momenta- 

 ry blackening of the asbestos occurred in both of the analyses of chloride of amvl 

 with oxide of zinc, but, as already intimated, was not regarded at the time of serious 

 consequence, as similar phenomena in the analysis of hydrocarbons by my process 

 were generally attended with good results. It may, therefore, remain an open 

 question, whether the oxide of zinc may not serve a good purpose in the analysis of 

 substances of the class now under consideration. 



