136 THE ANTARCTIC MANUAL. 
table is based on the same gravimetric data, namely the weight of 
mercury and of glass (b and d). From these the volumes are calcu- 
lated, taking 13°596 as the density of mercury and 2°6 as that of 
glass, and they are given in lines g and 7 respectively. When the 
specific heat of a body is spoken of without further qualification, the 
water value of 1 grm. of the substance is meant. When we are 
dealing with volumes, we require to know the specific heat per 
unit volume, and that is the water value of 1 c.c. of the substance. 
TasLE XV.—CALORIMETRIO SPECIFICATION OF THERMOMETERS. 
Computation of the Water Value of the Bulb from Data supplied by the Maker. 
Maker of thermometer . Fastré | Baudin | Tonnelot | Chabaud 
18°003 | 30°20 3-781 | 25°09 
0°60 1:01 0°126 0-828 
3°075 2°43 0:599 2°58 
0°61 0°49 0°120 0-511 
1:21 1°50 0° 246 1°339 
Weight of mercury,grms. . . - . « 
Water value of mercury, grms. 
Weight of glass, grms. . 
Water value of mercury, grms. a $3 
Water value of bulb, grms. cte= 
“SM © QA oes 
Calculation of Water Value of Bulb and of its Specific Heat per Unit Volume. 
Volume of mercury, c.c. —— =|g | 1:37 2°221 0°278 1845 
Water value of mercury, grms. 0°4486g = | h | 0°615 | 0°996 | 0°125 0°828 
Volume of glass, c.c. ‘ a ia 1:18 0°935 0:230 0-990 
Water value of glass, grms. 0°51487 = | k 0°607 | 0°481 0°118 0°510 
Water value of bulb, grms. . h+tk=| 1 1°222 | 1°477 0°243 1:338 
Total volume of bulb,ec. . . gti= | m| 2°55 3°156 | 0°508 2°835 
Specific heat of bulb per unit vol. m= | ® 0°474 | 0°475 0°484 0°472 
Centesimal Composition of the Bulb by Volume. 
Mercury volumes percent... . . . . | .. | 53°75 | 70°3 54°7 65°1 
Glass volumes percent. . . . |. | 46°25 | 29°7 45°3 34:9 
Now the density of a substance, when the metrical system is used, is 
the weight of 1 cc, therefore the weight of 1 cc. of mercury is 
13°596 grms. and that of the same volume of glass is 2°6 grms. 
Multiplying 13-596 by 0°033, the specific heat of mercury, we 
obtain 0°4486, which is the water value of 1 c.c. mercury, or its 
specific heat per unit volume. Multiplying 2°6 by 0°198, we obtain 
0°5148 as the specific heat per unit volume of glass. If now we 
multiply the volume of mercury, g, by 0°4486 and the volume of 
glass, 7, by 0°5148, we obtain A and k, the water values of the 
