676 PROFESSOR THOMSON ON THE ELECTRO-DYNAMIC QUALITIES OF METALS. 
Experiment VIII. February 23rd, 1854. 
Copper conductor reduced to two slips. 
1 
i 
1 
1 
(Current seven times six minutes in 
diiferences of temperature after 
By end next A. 
each direction.) Temperatures and 
;ight minutes of current entering 
By end next B. 
Diminutions of 
differences from 
middles to ends of 
periods. 
Periods. 
Ta* 
Tb- 
Tb-Ta = D. 
Ta- 
Tb- 
Tb-Ta = D'. 
D'-D. 
I. 
54*81 
56°*31 
1*50 
55*47 
56*88 
o 
1*41 
*09 
II. 
55*90 
57*32 
1*42 
56*37 
57*63 
1*26 
*14 
III. 
56*70 
57*99 
1*29 
57*16 
58*29 
1*13 
•16 
IV. 
57*49 
58*70 
1*21 
57*80 
58*91 
Ml 
*10 
V. 
57*80 
58*98 
1*18 
58*18 
59*20 
1*02 
•16 
VI. 
58*29 
59-80 
1*51 
58*37 
59*80 
1*43 
*08 
VII. 
58*27 
59*80 
1*53 
58*08 
59*50 
1*42 
*11 
Means for six periods... 
57*4083 
58*7650 
1*3567 
57*663 
58*888 
1*2283 
*1283 
Augmentation of differences during periods included *01 
Add average augmentation per half-period *0008 
Effect due to reversal of current 0"°1291> 
i in favour of Vitreous Electricity. 
54. The effect here shown is, as regards amount, unmistakeable, and it appeared 
quite to establish the conclusion I had not ventured to draw from the previous expe- 
riments on the copper conductor. As it was clear that diminution in the power of 
the conductor had now begun to augment its sensibility for the effect under investi- 
gation, I had it further reduced by cutting away from its breadth, above and below, 
between the heaters and the bends for the thermometer-bulbs on the two sides, and 
on the other sides of those bends as far as the coolers. An experiment was then 
made which led to the following results : — * 
Experiment IX. March 7th, 1854. 
Copper conductor diminished in breadth. 
(Current seven times six minutes in each direction.) Temperatures and 
Diminutions of 
differences of temperature after 
six minutes of current entering 
middles to ends of 
By end next A. 
By end next B. 
periods. 
Periods. 
Ta- 
Tb- 
Tb-T^=D. 
Ta- 
Tb- 
TB“‘TAi=D'. 
D'-D. 
I. 
58-61 
58*00 
1*39 
5^56 
58-98 
1*42 
-*03 
II. 
58*19 
59*69 
1-50 
58*74 
60*01 
1*27 
*23 
III. 
59*12 
60*70 
1*58 
59*61 
61*08 
1*47 
*11 
IV. 
59*91 
61*53 
1*62 
60*18 
61-75 
1*57 
*05 
V. 
60-50 
62-18 
1*68 
61 15 
62-53 
1*38 
*30 
VI. 
61-71 
63-02 
1-31 
61*87 
62*91 
1-04 
*27 
VII. 
61-07 
62-80 
1*73 
61*07 
62*62 
1*55 
*18 
Means for six periods... 
60-083 
61-653 
1*57 
60-4367 
61*8167 
1*38 
•19 
Augmentation of differences during periods included... *13 
Add average augmentation per half-period =*01083 
*20083 
