146 THE ANTARCTIC MANUAL. 
area of axial section is the product of the diameter of the cylinder 
and its length, and the effective axial area (y) is the axial section 
multiplied by 0:84; g is proportional to the quantity of the sun’s 
rays, which strike the bulb in unit of time. The term of cooling, h, 
is given in seconds, and its reciprocal 7, 38 the fraction of the excess 
L 
of heat lost per second during cooling. 
Taste XIX.—Exampie or Caortmetric Use or THERMOMETERS FOR DETERMINING 
THE RapIANT HEAT WHICH THEY ABSORB. 
Designation of thermometer . A B A B A B 
Stationary temperature reached z | 210-25) 18°-5 | 29°15] 19°-1 | 22°°4 | 19°-2 
in sun’s rays . °C. 
Difference between stationary 
temperature and that of the 
air. 2. we wee 
ee aah wees OE Psatl| m | 2-110 | 0-678 | 2-406 | 0-788 | 2-408 | 0-808 
Loss of heat persecond . . n 10°00844 0: 00561/0- 00962)0-00657/0 - 009990 - 00673 
ei edire dial seationa {| p {0-00686.0-00590}0-00782!0-00691}0-00812 0-00706 
Uf 69:25 | 89:5 | 7°15 § 4°°1 | 79-4 | 42 
i = ae 
Ratio ps: Po = q 0°860 0°896 0°869 
Designation of thermometer . A B A B 
Stationary temperature reached k 93°°] 19°-6 990-4 19°°2 
in sun’s rays . 
Difference between ies 
temperature and that of the 1 8°°1 4°°6 7T4 4°°2 
li es ee Sk 
Corresponding excess of heat Y . . : 
foie sa} m| 2°734 0-885 2498 | 0-808 
Loss of heat persecond . . | n 0°0109 0:00738 0:00999 | 0:00673 
eee ee ere noe ofp | 0-00889 | 0-00775 | o-o0812 | 0-00706 
Ratio pa: pp= | q 0°872 0-869 
In Table XIX. five separate observations of the stationary tem- 
perature reached by the thermometers side by side are given. The 
temperature of the air was 15°°0 C. The excess of heat in each bulb is 
m =ld,or the water value of the bulb multiplied by the excess of its sta- 
tionary temperature above that of the air. The loss of heat per second 
n= - as was above described; p = ; is the loss of heat per second 
referred to unit area of effective axial section. It has been pointed 
out that g, the effective axial area, is the sectional area of the bundle 
of solar rays which strikes the bulb, and it is therefore proportional 
to the supply of radiant heat by the sun to the thermometer. But 
when the temperature of the thermometer in the sun has become 
