372 
DR. J. P. JOULE OR A NEW DETERMINATION 
Thermal 
Temperature 
to which 
the brass was 
heated. 
T. 
Temperature 
Corrected 
Time 
Specific heat 
1 
capacity of 
in small vessel 
temperature 
occupied in 
uncorrected 
No. 
small 
vessel of 
before 
immersion of 
after 
immersion of 
transferring the 
brass to the 
for 
transfer. 
1 
water. 
VV. 
brass. 
T'. 
brass. 
T". 
small vessel, 
in seconds. 
(T" - T') W. 
(T-T") w. 
1 
4733-2 
901 -25 
174-78 
213-24 
5 
0-08964 
2 
4762-8 
900-58 
175-5 
213-8 
4 
0-08999 
3 
4747-0 
947-27 
213-26 
252-29 
3 
0-09032 
4 
4727-7 
952-13 
158-0 
200-56 
4 
0-09070 
5 
4750"3 
1030-46 
125-5 
173-52 
4 
0-0901 8 
6 
4724-6 
984-47 
210-36 
251-65 
3 
0-09019 
7 
4764-0 
1069-6 
197-95 
244-3 
4 
0-09065 
Average . | 
969-4 
or 104° -92 
179-34 
or 44° -08 
221-34 
or 47°'32 
J 3-86 
0-09024 
1 
4756-0 
894-49 
104-35 
14572 
30 
0-08903 
2 
47942 
985-82 
154-5 
197-44 
30 
0-08847 
3 
4717-4 
994-44 
165-33 
208-97 
30 
0-08880 
Average . | 
958-25 
or 104°-06 
141-39 
or 41°-16 
184-04 
or 44°' 44 
j 30 
0-08876 
From the above we may estimate the correction arising from the time of transfer in 
the first seven experiments at '00023, which, added to '09024, gives '09047 for the 
specific heat of brass at 76° compared with water at 40°. Regnault, in two trials, 
arrived at '0939, but this appears to be in reference to water taken as 1'008. When 
reduced to water taken as unity it becomes '09315, which still differs considerably from 
my result. The method of cooling used by Regnault in this instance does not appear 
to me to be capable of as great accuracy as the method of mixtures used by the same 
physicist for other substances. 
The interest I felt in this part of my subject induced me to try some experiments 
of a similar nature with copper sheet. It was tied in a bundle like the brass. Its 
weight w was 27 7 7 '9 grains. 
No. 
W. 
T. 
T'. 
T". 
Time of transfer. 
(T" — T') W. 
(T — T v ) w. 
1 
4734-5 
855 26 
199-3 
232-62 
6 
0-09121 
2 
4772-7 
900-58 
172-4 
209-57 
4 
0-09242 
3 
4738-5 
946-26 
218-85 
255-49 
5 
0-09048 
4 
4732-2 
948-07 
166-18 
206-18 
5 
0-09185 
5 
4786-3 
1030-46 
106-0 
152-48 
4 
0-09121 
6 
4749-0 
985-48 
197-02 
237-2 
4 
009180 
7 
4849-6 
1069-0 
103-35 
208-46 
4 
0-09152 
Average . | 
962 16 
or 104°-36 
16616 
or 43°-07 
214-57 
or 46° "80 
j 4-57 
0-09150 
1 
4749-9 
891-11 
106-6 
145-2 
30 
0-08848 
2 
4815-1 
985-14 
161-46 
201-14 
30 
0-08773 
3 
4768-0 
997-47 
170-35 
210-99 
30 
0-08869 
A verago . | 
957-91 
or 104° -03 
146-14 
or 41°-52 
185-78 
or 44°"58 
j 30 
0-08830 
