462 E. L. Nichols—Character and Intensity of the 
TasLe VIII, 
Comparison of the sun’s spectrum with that of glowing pla- 
tinum. 
Region. Reading. Mean. 9°—a, Intensity. 
106°3 l 
8 1065 106°-4 90° 0” 1-000 
106-4 J 
99-0 ) 
9 98-4 | 99-0 72 36 091057 
99°6 | 
67-0 ) 
10 68-0 | 67-5 51 6 060570 
675 ) 
45°0 3 0-22185 
11 vid 44:5 28 6 
31-0 0°12380 
12 aot 37-0 20 36 
ae 07600 
13 ot 32-4 16 0 0 
20°0 0-05529 
14 eg 30-0 13 36 
275 
J 0°03457 
15 27-0 27°25 10 43 
ag’? : 002781 
- 25°8 26-0 9 36 
23-9 : 0-01300 
WW 24-0 ¢ 23°95 6 33 
42° 0-00951 
18 21:9 ¢ 22°0 5 36 
20-0 2 
. 000394 
19 aos 20-0 3 36 
rature. 
Jsing the values, in the column marked “calculated 
(Table V), I have constructed a table which gives for Interv: 
of 25°, from 1200° to 1900° (platinum thermometer), the inten” 
sities corresponding to the wave lengths between scale-divis- 
ions 8 to 19 in terms of the intensity of the spectral-region co? 
_ Tesponding to division 10 when the platinum was at 1900°. f 
_,, This value was chosen as the unit becanse the position OF 
oS division 10 could be simply and accurately defined. bie 
_ Tegion corresponds so nearly with line D, that it may be defined 
as the region ering on line D, on the side nearest the vine = 
This table (IX) which may be, not inaptly, termed Jsothermi = 
1s arranged i ae 
ed according to temperatures. 
