164 REPORT—1896, 
The numbers are reduced from the table in the ‘Mémoires de I’In- 
stitut,’ tome xxi. p. 743, by assuming the mean specific heat of water for 
the calorimetric range of each experiment to be the specific heat of water 
as given in Rowland’s table for the mean calorimetric temperature of the 
experiment, and adding to the heat thus computed as that given out by 
one gramme of water in cooling from T° to the final calorimetric tempera- 
ture, the further amount which, upon an estimation based on Rowland’s 
data, would be given out on cooling to 0°. 
Some doubt has been thrown on the accuracy of the data quoted by 
Regnault in the table referred to. Ihave adopted Mr. Macfarlane Gray’s 
conclusion that the computations of the mean specific heat are correct, 
though the data are erroneously printed in Regnault’s papec. 
The results of the individual experiments are shown in the following 
table. In order to obtain a mean result a curve of differences (see figure) 
100 110 120 130 140 150 160 170 180 190 
Abscissee.—Air Temperatures (T.) 
Ordinates.—Differences (in Joules) between Total heat from 0° to T° and 4:2xT. 
between tctal heat at temperature T and 4:2 xT has been plotted, and 
the means of observations, collected into seven groups, have been taken 
and also plotted. These are indicated in the diagram by circular dots, 
the individual results being shown by crosses. 
Taste II.—Regnault’s Observations for the Total Heat of Water between 
0° C. and Various Temperatures (7') of the ‘ Air Thermometer’ above 
the Boiling -point of Water. 
(Reduced from Regnault’s and Row ae results. ea in ee ) 
Total Heat 
11691 | 492-46 | 491-02 | +1:44 
11854 | 498-76 | 497-87 | + :99 
120°39 | 50486 | 505-64 | — -78 
109-25 | 461-44 | 458-85 | 42:59 | 120°84| 50736 | 507-53 | — -17 
109-25 | 46094 | 458:85 | +2-09 | 12186 | 51272 | 51181 | + “91 
107-79 453°36 452°72 | + ‘64 
109°38 460°69 459-40 | +1:29 
‘ Nl | Total Heat | A 
av from 42xT Differ | Ak frm 42xT Differ- 
0° to T? | | 0° to T? ence 
I | i. 
4 | ° oe = 
107-70 |, 451-83 | 45234 | — ‘1 || 11660] 491°35 | 489-72 | +1°63 
| 
| 
| 
| 
107-90 | 45360 | 45318 | + 8 | 
| 
| 
| 
109°25 460 84 453°85 | +1:99 | lll 
110°80 465°76 465°36 | + ‘40 | ‘ 
111-51 467°60 468:34 | — ‘74 | 12891 5 
42°3 
113°86 47856 478-21 | + ‘35 || 180: 40! 548-07 | 547-69 | + 38 
