Table I.— Emissivity in Air at 39'3 Atmospheres (16° C.).* 
rUTAVKI., Tulilo 1. 
I. 
Electro¬ 
motive 
.force in 
volts. 
II. 
Current 
in 
amperes. 
III. 
IV. 
Current 
reversed. 
Electro¬ 
motive 
force in 
volts. 
Current 
in 
amperes. 
Before t 
he electri 
0 cm-i-ent 
was start 
0-3800 
22-36 
0-3816 
22 • 39 
0-761.5 
31-02 
0-7693 
31-20 
1-122 
,36 - 32 
1-137 
36-45 
1-5-23 
40-85 
1-630 
41-10 
1-800 
43-93 
1-818 
44-07 
2-035 
46-40 
2-066 
46-52 
Ten min 
utes aftei 
the electr 
ic current 
Mean 
electro¬ 
motive 
force. 
VI. 
Mean 
eurrent. 
YII. 
Power 
dissi¬ 
pated in 
watts. 
VIII. 
Resistance 
of 
radiator 
in ohms. 
IX. 
(R — Rq) 
where 
R = actual 
resistance 
R„ = re¬ 
sistance 
at 0° C. 
X. 
Tempera¬ 
ture of 
radiator 
in 
platinum 
XI. 
Tempera¬ 
ture of 
radiator 
in Centi¬ 
grade 
degrees. 
XII. 
Tempera¬ 
ture of 
enclosure 
in 
Fahren¬ 
heit 
degrees. 
XIII. 
Tempei'ji- 
ture of 
enclosure 
in Centi¬ 
grade 
degrees. 
XIV. 
Tempera¬ 
ture 
difference 
* = (<,--4) 
where 
t, = temp, 
of radiator, 
4 = temp, 
of 
enclosure. 
XV. 
Power 
dissipated 
in watts 
per degree 
Cepti- 
gi’ade. 
XVI. 
Emissivity t 
in C.G.S. 
units. 
0-3808 
0-7664 
1-130 
1-527 
1- 809 
2- 046 
was stopped 
22-38 
31-11 
36-39 
40-98 
44-00 
46-46 
8-522 
23-81 
41-11 
62-57 
79-60 
95-01 
0-01701 
0-02460 
0-03105 
0-03726 
0-04111 
0-04402 
0-00684 
0-01443 
0-02088 
0-02709 
0-03094 
0-03385 
179 
377 
546 
708 
809 
886 
181 
396 
689 
790 
923 
1028 
69-5 
61-0 
62-5 
64-5 
67-0 
69-0 
71-0 
59-0 
15- 3 
16- 1 
16-9 
18-0 
19- 4 
20 - 6 
21-7 
15-0 
165-1 
378-1 
671-5 
771-0 
902-5 
1008-7 
0-05162 
0-06298 
0-07195 
0-08116 
0-08819 
0-09438 
XVII. 
Tempera¬ 
ture of 
water 
circula¬ 
tion at 
exit. 
XVIII. 
Tempera¬ 
ture of 
pressure 
gauge. 
0-003724 
0-004544 
0-006191 
0-006866 
0-006363 
0-006809 
15- 8 
16- 2 
16- 4 
16-8 
17- 2 
17- 9 
18- 2 
15-7 
18-3 
19-7 
XIX. 
Zero of 
pressure 
gauge. 
44 
83 
XX. 
Pressure 
gauge 
reading. 
45- 40 
46- 41 
45-85 
45- 95 
46- 10 
46-18 
46-28 
46-3 
XXI. 
XXII. 
XXIII. 
XXIV. 
XXV. 
XXVI. 
PiVi where 
Pressure 
Vi = original 
V., 
Ib 
Pi 
volume 
voinmo 
corrected 
corrected 
Tempera- 
Pi = original 
cal- 
for the 
for the 
tiiro of 
pressure at 
ciliated 
— UUl- 
weight 
deparUu-e 
standard 
temperature 
from 
of 
of air 
resist- 
given in 
column 
morcui-y 
from 
unco. 
column 
XX. 
column. 
Boyle’s 
XVIII. 
law. 
77-03 
1-97 
39-10 
39-85 
39-26 
17-3 
77-08 
1-96 
39-33 
40-08 
39-48 
— 
77-13 
1-89 
40-81 
41-56 
40-92 
— 
77-19 
1-87 
41-28 
42-03 
41-38 
19-0 
77-24 
1-83 
42-20 
42-95 
42-27 
— 
77-29 
1-82 
4-2-47 
43-23 
42-55 
- 20-1 
77-34 
1-80 
42-97 
43-73 
43-04 
— 
77-40 
1-99 
38-90 
39-64 
39-06 
18-3 
’ tor eacn column in tne loiiowing tames a siuiuar set uuaoi vauiuiio woio ..—..., -- x _ 
t The emissivity is numerically equal to the heat dissipated per sq. contim. of surface of the radiator per second per degree Centigrade temperature interval, the heat being expresse 
A = Current in amperes. S = sui'face of radiator. 
V = electromotive force in volts. ^ = 1 1 ' — tx — temperature of radiator — temperature of enclosure. • 
Ohs&t'mtims. 
in water-gramme-degrees (therms) or 
,, V X A . 
E., where 
The diameter of the bright platinum radiating wire was 1*106 millims. 
The length between potential contacts . . . . 9 * 498 centims. 
The superficial area.3 ■ 300 sq. centims. 
The resistance of the radiator was at 100 G. = 0*01398/ 
at 0“ C. = 0*010165 
Therefore the temperature coefficient = 0*00003822 
5l = 1-3759 
Rq 
The fundamental coefficient = — ^ = 0*003760 
lUOxvi 
Where Ei = resistance at 100° C.; R„ = resistance at 0' C. 
In the formula (t - Pi) = 6 [( 3 ^) - coefficient <J was 8 = 1-495. 
The temperature of the Clark’s cel! was 17-3; it was balanced at 1-4317 on the potentiometer. 
