88 
DE. A. MATTHIESSE]S^ AjS'D DE. M. HOLZMAXX OX THE 
air. Thus copper, chemically purified, was fused with borax and chloride of sodium 
(the flux not quite covering the surface of the melted copper). The conducting power 
of this specimen was 
O IV^AHTl 
fa. 69-44 at 24-2'| 
l.h. 69-38 at 23-5169-37 at 23-9 
[c. 69-30 at 24-oJ 
This was then kept fused for several hours in a porcelain tube in a cmrent of hydro- 
gen ; it then conducted — 
II 
ia. 
'\h. 
87-20 at 18-8 
b. 85-50 at 19 
■01 
Mean. 
86-35 at 18-9 
This was next treated in the above-described manner in the tobacco-pipe, first for half 
an hour, and then for three hours, which caused the conducting powers to increase to 
the following values : — 
89-32 at ifo] . 
III. After half an hourJ^. 91-07 at 17-8 >89-57 at 17-4 
[c. 88-40 at 17-4) 
IV. After three hours . 
a. 92-63 at 18-0 
b. 93-36 at 19 
■^| 93 - 
•2J 
00 at 18-6 
Similar results were obtained with galvanoplastically precipitated copper, which had 
been fused in contact with air under a small quantity of borax and chloride of sodium. 
Means. 
II. No. 1, fused in a tobacco-pipe for half an hour, as 
above described 
III. No. 1, fused one hour in pipe 
IV. No. 1, fused for one hour and three-quarters in pipe 
V. No. 1, fused for three hours in pipe 
a. 
73-20 
at 
b. 
73-08 
at 
G. 
73-69 
at 
a. 
76-27 
at 
b. 
75-55 
at 
c. 
75-38 
at 
a. 
83-14 
at 
b. 
82-25 
at 
'a. 
90-36 
at 
b. 
91-00 
at 
a. 
91-92 
at 
.b. 
92-76 
at 
;- 8 | 
^-oJ 
82-70 at 16-9 
90-68 at 19-7 
92-34 at 18-3 
From the above experiments we see how difficult it is to reduce the whole of the sub- 
oxide ; a fact, which explains the reason why no good determinations as to the amount 
of oxygen present in copper have as yet been obtained. 
