- 
304 J. M. Silliman—Examination of the Bessemer F lame. 
f a grain, or thirty times that given for sodium. By the time 
the lithium line is established the red potassium line at 233° 
and occasionally the violet line at 135° appear, and the blue and 
green fields become divided into bands which are so rapidly 
resolved into bright and dark lines, that it is difficult to note 
the exact time of the appearance of each. The spectrum in 
creases to a dazzling brightness, and ati itself in both direc- 
tions until it reaches from 234° to 140°. 
During the third period the Leta becomes more brilliant, 
and ~ =n more distinct. Several new lines make their 
swept away with the others, and at other times en a 
visible. In either case the change i is very decided, and does 
not generally occupy more than three seconds. In ‘the course 
of my observations, “eal er ag lines have been detected, as 
- given in the table below 
Some of the lines given by Lielegg I have failed to _— but 
have detected others not given by him. 
Ist Period, 234, 35, 50, 135. 
24 Period, 234, 89, 43, 44, 443, 454, 46, 473, 48}, ri 52, 53, 56, 
64, 614, 62, 624, 63, 65, 664, 674, 70, 72, 120, 135 
3d Period, 234, 35, 43, ‘44, 444, 454, 46, 474. 484, a 514, 52, 53, 
56, 5 7, 614, 62, one 68, 65, 664, 67, 674, 70, 72, 
100, 102, aca 105, 108, 
Among the dark bands iia “— most intense occurred 
at 4446, 51-55, 56-58, 62-64 ; others were found at 33-845, 
364, 374, 384, 40, 68-72. 
Many of the dark bands were crossed by bright lines. 
I have repeatedly observed the dark band considered by 
‘ Roscoe to be a hydrogen absorption line, but have not noticed 
that its intensity varied with the dampness of the weather. 
Whether it is an absorption band or not can be determined by 
a series of observations continued through wet and dry hogee 
If this proves to be a hydrogen line, the Bessemer spectrum w 
be found — oo than is generally supposed. It has 3 
