OP HOT-EOLLED AND COLD-EOLLED MALLEABLE lEON. 
275 
Order of 
position, or 
experiment. 
Xo. of bar. 
Order of 
position, or 
experiment. 
No. of bar. 
Order of 
position, or 
experiment. 
No. of bar. 
1 
1 
9 
3 
17 
5 
2 
7 
10 
9 
18 
11 
3 
13 
11 
15 
19 
17 
4 
19 
12 
21 
20 
23 
5 
2 
13 
4 
21 
6 
6 
8 
14 
10 
22 
12 
7 
14 
15 
16 
23 
18 
8 
20 
16 
22 
24 
24 . 
The bars, when on the equatorial plane, were struck in the order 1 to 24 of the “ Order 
of Position, or Experiment ; ” when on the dip plane, they were struck in the opposite 
order. They were always placed on the experimental stage under the compass in the 
order 1 to 24 of the “ Order of Position, or Experiment.” A printed skeleton form had 
been prepared, and the entries in it of the compass-readings were made without the 
shghtest risk of confusion. The lettered end of the bar was always in the first instance 
placed towards the east ; and, as soon as the compass-card was read, the bar was reversed 
in length, and its lettered end placed towmrds the west, and the compass-card was again 
read. The difference between these two readings (which has been carefully verified by 
examination, and by collateral formation and difference of sums of readings) is the 
number recorded in this paper. The zero, or card-reading when no bar was near, was 
usually taken at the beginning and at the end of each experiment, merely to enable me 
to detect erroneous readings, but no further use was made of it. 
In two instances in Experiment 13, the presumption of error of 5° (undetected at the 
proper moment) was so strong, and the uncertainty as to the side on which the error 
was made was so great, that I judged it best to omit them, and to multiply the result 
for four bars by f , in order to produce the result for six bars. 
The “ Diff. readings ” in the following Tables denotes the excess, with its proper alge- 
braical sign, of the compass-reading when the lettered end of the bar is East above the 
compass-reading when the lettered end is West, and is taken as measure of the inten- 
sity of magnetism of the bar. When the bars have been struck with the lettered end 
downwards, the “ Diff. readings ” is positive. 
Experiment 1, 1862, February 6, O'". 
The bars were brought from the painting-room, and were immediately tried. 
Hot-rolled 
Hot-rolled 
Cold-rolled 
Cold-rolled 
longitudinal. 
transTersal. 
longitudinal. 
transyersal. 
No. 
Diff. 
No. 
Diff. 
No. 
Diff. 
No. 
Diff. 
readings. 
readings. 
readings. 
readings. 
o / 
O / 
+ i 0 
+ 25. 20 
1 
+ 18 5 
7 
+ 5 15 
13 
19 
2 
+ 13 30 
8 
+ 7 40 
14 
+ 80 
20 
+ 14 5 
3 
+ 14 30 
9 
+ 7 45 
15 
+ 7 20 
21 
+ 18 20 
4 
+ 70 
10 
+ 7 30 
16 
+ 1 10 
22 
+ 12 50 
5 
+ 11 20 
11 
+ 6 50 
17 
+ 20 30 
23 
+ 6 20 
6 
+ 12 10 
12 
+ 3 40 
18 
+ 70 
24 
+ 17 30 
Sum... 
+ 76 35 
Sum... 
+ 38 40 
Sum... 
+ 45 0 
Sum... 
+ 94 25 
Total sum . . . 40'. 
2 P 2 
