274 



Hartley — The Action of Heat on the Absorption Spectra and 



At 40°, tlie red rays, like bands of red light, have blended, and appear to have 

 retired to the upper part of the liquid where the layer is thinnest. The opacity of 

 the liquid has greatly increased by rise of temperature. 



At 85°, measurements were made at D, X 598; the rays were absorbed as far as 

 X 588, and then transmitted to 423. The red rays transmitted near B were only 

 very dimly seen. 



At 100°, measurements were made at X 581, and at the extremity of the 

 spectrum X423. A dark band was situated about X 581. 



Cohalt Bromide^ CoBr2'6H20. — Aqueous solution, saturated at 20° C, of a 

 purple colour. Thin wedge, gas-light. This solution absorbs moisture from the 

 air. It was found that 6'692 grs. of the hexahydrate CoBra'GHoO dissolve in 

 2*129 grs. of water at 16° C, or the salt is soluble in about one-third of its 

 weight of water. Another experiment gave 9'6819 grs. in 2*955 grs. of water, 

 the specific gravity of the solution being 1*6284 at 16°* 3 C. 



At 16" C. 



At 100° C. 



Eays transmitted from 



to 

 Absorption Band, 

 Spectrum ends at 

 Rays transmitted from 



to 



The liquid was almost opaque ; measurements made with difficulty. 



Cobalt Bro77iide, CoBr2*6H20. — Solution in alcohol, of a blue colour, 

 wedge cell, sunlight. ^ 



Rays transmitted from ..... 753 



\ 

 753 

 741 

 631 to 598 

 512 

 581 

 545 



Thin 



At 16° C. 



to 



741 

 631 to 598 



598 

 512 

 581 

 545 



Absorption Band, 

 Eays transmitted from 

 Spectrum ends at 

 At 100° C. . Rays transmitted from 

 to 

 Solution almost opaque. 



Cobalt B7-omide, CoBr2'H20. — Glycerine solution. Thin wedge cell. Purple 

 colour. 



At 16° C. . Rays transmitted from 

 but feebly to 

 Rather more strongly to 

 Feeble Absorption Band, 

 Rays transmitted from 

 to end of Spectrum at 

 At 100° C. . The solution is unchanged. 



Cobalt Bromide^ CoBrj-eHsO. — Dissolved in absolute alcohol. A freshly pre- 

 pared solution of a blue colour. Thin wedge. 



Thin wedge cell. 

 X 

 741 

 724 

 685 

 . 685 to 536 

 536 

 473 



