140 , REPORT—1862. 
drawn off easily, and sealed hermetically bya lamp. The wire being soldered 
to the thick copper connectors, and the corks fitted into the tube, dry carbonic- 
acid gas was led through it for the space of about six hours, for the purpose 
of drying it perfectly, as well as of displacing the air contained in it; after 
which the small glass tubes were melted off at the points, when they have 
been previously drawn out. Tin caps, filled with melted marine glue, were 
then fitted over the corks and the ends of the tube, to prevent diffusion of the 
carbonic acid and air through the corks. The whole of the tin caps outside, as 
well as those parts of the copper-wire connectors which dipped in water of 
the bath in which they were placed whilst being tested, were covered with a 
thick coating of marine glue. 
The wires experimented with were as follows :— 
2, Silver: annealed -........, f Cut from the some piece; pure 
3. Silver: hard-drawn ....:... ees from the same piece, but different 
4, Silver: annealed ,...../... {from 1 and 2; pure. 
. Copper: hard-drawn ...... : 
é io annealed . grccitier syn orgie mag baka bat 1 
7. Copper: hard-drawn ...... Cut from the same piece, but different 
8. Copper: annealed.......... from 5 and 6; pure. 
9. Gold: hard-drawn ........ C ‘ 
10. Gold: annealed.....:....:. mi from the Same pices _ pure. 
11..Gold: hard-drawn.......... Cut from the same piece, but different 
12., Gold :,annealed.... .«.¢.2.-+s+ from 9 and 10; pure. 
13. Platinum: hard-drawn 
14. Platinum: hard-drawn F 
15. Gold-silver alloy : hard-drawn | Cut from same piece. Made by Messrs. 
16. Gold-silver alloy; hard-drawn { Johnson and Matthews. 
17. German silver: annealed .... Cut Homie, same, misee "giles 1am 
18. German silver: annealed.... Tapped ims sdomper connectors, and 
19°C danaey wil var AGE aIad used as normal wire with which the 
f ; rae rest were compared. 
‘*** | Cut from the same piece ; commercial. 
The reason why duplicates were made in each case was that, in case any of 
them should by any cause get damaged, the experiments might be continued 
with the duplicate. When being tested, they were placed in a large bath 
containing from 40 to 50 litres of water. By testing the wires at 20° it was 
found easy to keep that temperature in the bath, during the experiments, to 
0-1° or 0:2°. 
Up to the present time, that is to say, four months since they were first 
tested, the conducting power of the wires 1, 3, and 5 has altered, owing to 
becoming, in all probability, partially annealed. Wire 8 has also altered mate- 
rially, having decreased in conducting power 3:5 per cent.: this decrement may 
be possibly due to bad soldering. The differences found with the other wires 
are so very small, that it is impossible to say whether they have altered or not; 
for 0:1° or 0-2° will account for them. It was, therefore, thought better to wait 
for another two or four months before giving an opinion as to whether they alter 
or not; for as the wires are in tubes and only surrounded by carbonic acid, we 
can never be absolutely sure that the wire has exactly the same temperature 
as the bath, more especially when it is considered that each time the con- 
nexion with the battery is made the wire becomes somewhat heated. 
If, two or four months hence, they still show no difference in their con- 
ducting powers, it is proposed to expose the one set to variations of tempera- 
