378 
DR. J. P. JOULE ON A NEW DETERMINATION 
Table II., Part 2. — Experiments with Friction of Water and Brass. Weight, W, 
lifted, 18229'0 grains. Average proportion of metallic to total friction, ^ 3 . Time 
occupied by each experiment, 4L m . V=0 o, 077214 ; P = 277386. 
Mean 
Rise of 
Mechanical 
Number of 
Capacity 
Mean 
corrected 
equivalent, 
No. 
revolutions. 
of the 
calorimeter. 
temperature 
of the 
temperature 
of the 
Difference. 
temperature 
of the 
for 
radiation, &c, 
T. 
or 
RWP 
U. 
calorimeter. 
atmosphere. 
calorimeter. 
C T 
V 
1 
4898 
5 
84349 
7 
286 -242 
271 
743 
14-499- 
47-686 
48-898 
773 
94 
2 
4826 
5 
84242 
7 
288-94 
277 
634 
11 -306- 
47 -477 
48-223 
774 
09 
3 
4929 
75 
84191 
7 
296 -43 
298 
242 
1 -812 + 
50-046 
49 144 
776 
48 
4 
4839 
5 
84324 
0 
324 -9 
311 
823 
13-077- 
47 -288 
48 -278 
774 
80 
5 
4829 
5 
84270 
0 
336 -865 
312 
924 
23-941- 
46119 
48 -153 
775 
93 
6 
4734 
3 
84256 
0 
311 387 
303 
190 
8-197- 
46 -893 
47 342 
773 
74 
7 
4897 
5 
84234 
5 
320 1 
308 
110 
11 -990- 
4S -168 
48-996 
773 
84 
8 
5061 
7 
84295 
7 
306 -684 
303 
So7 
3 -347- 
50 -640 
50 -378 
777 
30 
9 
5091 
8 
84294 
0 
330 -182 
321 
677 
8 -505- 
50-237 
50 -922 
773 
88 
10 
5165 
9 
84250 
0 
330 -3 
328 
046 
2 -254- 
51 -800 
51 -805 
772 
38 
11 
5045 
2 
84302 
0 
307173 
309 
280 
2 107 + 
50 -820 
50 -374 
775 
28 
] 2 
4613 
66 
84292 
0 
315 95 
324 
655 
8 705 + 
47 250 
46 337 
770 
62 
13 
4733 
9 
84304 
0 
342 -25 
343 
864 
1 614 + 
48 -326 
47 081 
778 
11 
14 
4782 
17 
84284 
0 
335 -99 
333 
819 
2-171- 
47-771 
47 660 
776 
73 
15 
4834 
0 
84244 
0 
338125 
333 
930 
4 -195- 
48-225 
48-456 
771 
42 
Average 
■1 
318-101 
or 54° -76 
} - 
•• 
•• 
774 
57 
Instead of reckoning one-half of the revolutions which took place in the acts of 
starting and stopping the wheel, as was done in the case of Table I., I have eliminated 
them in the last and subsequent Tables by starting the wheel till the scales were 
raised for an instant and then immediately stopped it at some period in each experi- 
ment for determining radiation. The revolutions called r in the first part of the Table 
being subtracted from the revolutions called II + r in the second part, give the numbers 
used in calculating the equivalent. This latter plan obviated some slight error to 
which the former method was possibly liable. 
The irregularities in the values of R arise from the variations from time to time in 
the friction of the bearing which supports the calorimeter on the axis. In the subse- 
quent experiments I adopted a method which removed nearly the whole of the metallic 
friction. In fig. 1 , v and w represent two concentric vessels. The inner one has a lid 
surmounted by three uprights, such as that represented by fig. 5. When water is 
poured into the space between the vessels, the uprights are raised so as to press 
against the bottom rim of the calorimeter, thus relieving its weight on the axis. The 
arrangement was eminently successful in producing an almost absolute uniformity of 
motion. 
