OF BROMINE AND OF IODINE MONOCHLORIDE. 
211 
increase in the number of bands in the green is observed, none of the bands from 5679-5 
to the end (5276-1) being visible at the lower temperature. No change in the position 
of the bands or lines common to the vapour at both temperatures is, however, observed 
on heating or cooling, so that in other respects, and as regards by far the majority of the 
lines or bands, no alteration is produced by heat. 
II. Absorption-Spectrum of Iodine Monochloride. 
Colour 
Wave-length. 
Wave-length. 
Red 
Orange 
Yellow ... 
6475-1 
6442-9 
6421-3 
6383-7 
6372-6 
6324-9 
6318-0 
6266-8 
6216-9 
6181-5 
6167-9 
6155-0 
6122-6 
6112-8 
6079-2 
6071-3 
6040-9 
6033-2 
6021-3 
6005-2 
5995-9 
5974-1 
5957-3 
5944-3 
5918-7 
5905-1 
5886-7 
5877-8 
5861-4 
5852-3 
5843-7 
5820-5 
5815-9 
Yellow ...< 
Green. 
5788-8 
5782-0 
5751-0 
5744-4 
5719-6 
5713-0 
5685-8 
5679-5 
5658-3 
5650-0 
5632-1 
5628-6 
5618-4 
5600-7 
5590-0 
5572-0 
5561-3 
5552-9 
5535-4 
5523-6 
5508-4 
5501-3 
5482-5 
5459-5 
5435-1 
5412-1 
5394-3 
5368-1 
5349-8 
5330-0 
5315-5 
5295*0 
5276-1 
f 
v.f. 
s. 
f 
• A careful comparison of the absorption-spectra of bromine and iodine monochloride 
shows that although a large number of bands are nearly coincident, the spectra, as a 
whole, are not identical either when the vapours are examined at low or at high tem- 
peratures, or when the length of the columns of absorbing gas is varied. Out of the 
66 lines mapped in each of the two spectra only two, viz. 6475-1 and 6372*6, appear 
to be truly coincident. The differences between the two spectra are seen, first, in the 
red portion, inasmuch as six bands are observed in the bromine beyond the last, 
6475-1, in the iodine monochloride; and, secondly, in the green portions, where the 
