1058 
PROFESSOR W. N. HARTLEY ON 
Plate 10. 
Blowing’ commenced at 12 lirs. 45 min. p.m. 
“Blow” inteiTupted at 12 hrs. 49 min. 
Blowing re-commenced at 12 hrs. 55 min. 
h. 
m. 
s. 
h. 
m. 
s. 
1st exposure at .... 
.... 12 
58 
30 
to 
12 
59 
30 
2nd „ 
.... 12 
59 
30 
•tl 
1 
0 
30 
3rd „ „ .... 
.... 1 
0 
30 
1 
1 
30 
4tli „ ,, .... 
.... 1 
1 
30 
1 
0 
30 
Sth „ 
.... 1 
2 
30 
1 
3 
30 
6tli „ „ .... 
.... 1 
3 
30 
1 
4 
30 
7th „ „ .... 
.... 1 
4 
30 
1 
5 
30 
8tli „ „ .... 
.... 1 
5 
30 
1 
6 
30 
9tli „ „ .... 
.... 1 
6 
30 
1 
7 
30 
10th ,, ,, . . . . 
.... 1 
7 
30 
1 
8 
30 
11th „ ,, .... 
End of “ blow.” 
.... 1 
8 
30 
11 
1 
9 
0 
Spectra of the Bessemer Flame. 
Description of the Sp>ectrum of the Bessemer Flame, as 'photographed at Crewe, 
January, 1893, at the Steel Works of the London and North-Westei'n Raihvay 
Company. 
The lines of the alkali metals appear, and are, in fact, the only prominent lines 
during- the first period of the “ blow,” when the silicon is being oxidised and slags are 
in course of formation. During the second period, or the “ boil,” the flame exhibits a 
continuous spectrum of bright rays, overlying which is a number of bright bands; 
some of these appear to be degraded towards the least refrangible rays, others do not 
appear to be degraded, but are bounded by lines, or by very narrow bands, possibly 
by the sharp edges of bands. There does not appear to be any distinct fading away 
of bands in the direction of the least refrangible rays more than towards the blue. A.t 
the commencement of the “ boii ” the bands are not so numerous as afterwards, nor 
are the lines so strong and numerous as subsequently, excepting the lines of the alkali 
metals. It is noticeable that certain lines appear only at the commencement of the 
“ boil,” others do not appear until the end. There is no very great difierence between 
the spectra taken at the close of the “ boil,” and at the commencement of the third 
period, or “ fining stage.” But both in the second and third periods there are several 
lines which are short, and seen only at the base of the flame ; others are broad at the 
base of the flame, like bands, but towards the tip they attenuate into lines. By far 
the greater number of the lines in the spectra are iron lines; especially rich in these 
lines is the ultra-violet region. The prominent bands, for the most part occupying 
the region of less refrangibility than \ 3000, are due to metallic manganese. They 
