RADIATION IN ABSOLUTE MEASURE. 
611 
Table VI.—Copper globe silvered and very highly polished for experiment of April 14; 
believed to be tarnished during experiment of April 17. (Apparatus, fig. 2.) 
April 14, 1890. Vacuum. 
Pressure at commencement about 10 M or 
12 M, coming down in 25 minutes 
to less tnan M, and kept so, though 
somewhat variable, by vigorous working 
of Sprengel. 
Temperature of bath surrounding enclosure, 
1.3°-3 C. 
Excess of tempei’ature 
of globe above tempera¬ 
ture of suiTOundings. 
Loss of heat per sq. 
centim. per second j^er 
1° C. of excess. 
240°5 
5-58 X 10-5 
2.33-4 
5-10 
227-2 
4-06 
222-3 
3-07 
218-7 
2-68 
211-4 
2 64 
208-4 
2-55 
205-7 
2-59 
202-9 
2-59 
198-2 
2-16 
195-9 
2-25 
193-6 
1-95 
191-5 
1-64 
187-7 
1-73 
183-9 
1-86 
179-9 
1-77 
176-6 
1-90 
174-9 
1-90 
167-9 
1-92 
164-5 
1-94 
161-2 
1-94 
April 17. Vacuum. 
Pressure 2 M. 
Considerably more at commencement. 
Temperature of bath surrounding enclosure, 
12° C. 
Excess of temperature 
of globe above tempera¬ 
ture of surroundings. 
Loss of heat per sq. 
centim. per second per 
1° C. of excess. 
254-5 
8-39 X 10-5* 
246-6 
8-21 * 
235-1 
7-35 
214-7 
7-28 
199-8 
7-18 
184-3 
6-98 
171-2 
6-87 
159-3 
6-66 
146-0 
6-57 
136-1 
6-31 
Vacuum unsatisfactory, improving by working pump. Surface of globe found to be tarnished at 
conclusion of this experiment. 
