202 Harttey—Zhe Action of Heat on the Absorption Spectra and 
A series of photographs of spectra was taken from CoCl,°6H,O in a saturated 
solution prepared at 20° C., but heated to 53° C. and allowed to cool. Cadett and 
Neall’s Lightning Spectrum plates were used, but they gave photographs with too 
little density. - 
The thinner part of the cell was observed and the coolest solution :— 
r 
Spectrum begins at . : : : : : : 656 
Rays transmitted to 6 6 . . : 560 
But there are three Absorption Bands visible between 
A 656 and 612. 
First band, feeble, . ‘ : : A : . 656 to 642 
Second band. : : ; : : : . 642 to 627 
Third band. F : ; : : og OY tho CID 
Great Absorption Band. : ; : : . 565 to 474 
Rays transmitted from . 0 : 0 : : 474 
to beyond. . : . . : 330 
The first, second, and third bands are degraded on the less refrangible side, 
as on Plate XVIII. 
The thicker layer of liquid examined :— 
r 
Rays transmitted feebly from . : . : 9 627 
to . . 2 . : 584 
Great Absorption Band. : : : ‘ . 584 to 436 
Rays transmitted from. : : : 5 : 436 
to beyond . . 6 ' : . 330 
The thicker part of the cell at or about 50° C.:— 
Spectrum begins feebly at : . 6 3 6 612 
Rays transmitted to : . 6 : . 584 
Great Absorption Band . ; : : . . 584 to 442 
Rays transmitted from . 6 : : 6 6 443 
to beyond . : . . . . 330 
The thinner layer of liquid at the lower part of the cell at 50° C. :— 
Xr 
Spectrum begins at . : 6 6 6 0 5 623 
and continues to . : 3 5 6 : 6 584 
There is evidence of an Absorption Band between . 6238 and 620 
And another Absorption Band between é . 620 and 612 
Great Absorption Band. : : ‘ : . 984 to 465 
Rays transmitted from. j : . : ; 465 
to beyond. c 0 ‘ : : 330 
Cobalt Chloride, CoCl,6H,O, dissolved in absolute alcohol.—The solution 
looked blue, but of rather a different tint to that of the hot aqueous solution ; it 
was also more transparent. The band of red light transmitted near C was dis- 
