ELECTEIC CONDUCTING POWEE OF PUEE COPPEE AND ITS ALLOYS. 
87 
with a carbonic acid gas apparatus, through the lower one passes a clay tobacco-pipe, to 
the stem of which is joined the bottle evolving hydrogen. The hydrogen is washed with 
Fig. 1. 
potash, nitrate of silver, and concentrated sulphuric acid, and the carbonic acid gas with 
bicarbonate of potash and strong sulphuric acid. The metal (about 8 grms. were taken 
for each experiment) was placed in the bowl of the pipe, and so fused in a current of 
hydrogen ; when fused, the hydrogen bubbled up through the melted metal ; thus by 
offering a fresh surface to the hydi’ogen, any suboxide that might be present was reduced ; 
and when making the copper alloys complete mixture was effected. When the hydro- 
gen had passed through for a certain length of time, the india-rubber tubing was dis- 
connected from the sulphuric acid bottle, and the fused Fig- 2. 
metal carefully sucked into the pipe-stem, forming, as 
shown by fig. 2, a ware which might, if necessary, be 
drawn finer. The carbonic acid gas was used to help 
to drive the air out of the muffle, as well as in some experiments which will be pre- 
sently detailed. 
In order to test the method, copper No. 3 was fused in the pipe, and kept so for 
about half an hour, when we found the conducting power — 
Mean. 
92-99 at 17°-5. 
In this manner we have been able to reduce the suboxide in the copper by degrees: 
all the alloys made were fused in this manner, only substituting carbonic acid gas in 
cases in which hydrogen could not be employed. 
e did not try to determine quantitatively the amount of suboxide present in the 
copper, as we know of no method which will give results which can be depended upon*. 
We shall only give the conducting power of copper that had been fused in contact with 
* Dick (Phil. Mag. June 1858) could not obtain any good results by any of the known methods. All 
the experiments which we have made agree with his, especially concerning the action of ammonia on copper. 
N 2 
a. 92-57 at 17-81 
d. 93-40 at 17-2J 
