88 PROCEEDINGS OF THE AMERICAN ACADEMY 



Its boiling-point was found to agree essentially with that assigned to 

 pure chloroform in Gerhardt's Iraite de C/iimie. When the usual tests 

 were applied, no impurity could be detected. 



Experiment 1. — A mixture of oxide of lead and asbestos was placed 

 in the anterior end of the combustion tube, between c and d, Fig. 2, 

 as previously described. As chloride of lead was supposed to bear a 

 pretty high temperature, without volatilization or decomposition, the 

 use of the air-bath was omitted in this experiment, and the oxide gen- 

 tly heated with a small flame from the combustion furnace. The com- 

 bustion had not proceeded far, when it became apparent, from deposi- 

 tion of minute drops of liquid on the sides of the vacant part of the 

 tube, — from b to c, Fig. 2, — that the combustion of the chloroform 

 was incomplete, although no doubt could exist as to the presence 

 of an excess of oxygen. This deposit of liquid, which, as already 

 stated, was supposed to be a chloride of carbon, was found to be dif- 

 ficultly volatile, suffering partial decomposition, and leaving on the 

 tube a brown deposit, which was not entirely removed by ignition in a 

 stream of oxygen. The high temperature employed to burn off this 

 deposit occasioned excessive heating of the posterior end of the mix- 

 ture of lead oxide and asbestos ; and this may have been the cause, to 

 some extent, of the excess in the determinations of carbon and hydro- 

 gen, although subsequent analyses indicate that the sample of chloro- 

 form under examination contained a larger percentage of these ele- 

 ments — particularly of the latter — than belongs to pure chloroform. 

 This experiment gave 11.47 per cent of carbon, and 1.87 per cent of 

 hydrogen. Theory gives 10.07 per cent of carbon, and 0.85 per cent 

 of hydrogen. The mixture of asbestos and oxide and chloride of lead 

 was removed from the tube, and treated in the usual manner with a 

 solution of bicarbonate of soda to obtain a soluble chloride. This op- 

 eration was found extremely tedious. Even after treatment for more 

 than two weeks, with occasional fresh portions of the bicarbonate and 

 frequent agitation, the decomposition of the lead chloride was still found 

 to be incomplete, and the operation was abandoned. As this is given 

 in the text-books as a good process for the separation of chlorine from 

 chloride of lead,* I am led to presume that in this case the excess of 

 heat employed gave rise to the formation of an oxychloride, which is, 

 doubtless, more slowly acted upon by the bicarbonate. This single 



* H. Hose, Ctiimie Analytique, iiew French edition, p. 801. 



