ABSORPTION SPECTRA AND CHEMICAL CONSTITUTION, 339 
Similar colour effects are produced by evaporating the solution of these 
salts, particularly of the sulphate. There are three hydrates formed, and 
eventually two hydrates and an anhydrous salt. 
Ueber die Wandlung der Spectren verschiedener Farbstoffe.* 
By Hermann W. VOGEL. 
Tt is a known fact that absorption spectra of one and the same 
substance dissolved in different liquids do not always show the absorption 
bands in the same position. According to Kundt’s law the broadening or 
shifting of the bands towards the red occurs owing to the greater 
dispersion or refraction equivalent of the solvent liquid, and this law holds 
good in very many cases. But there are cases where, on a change in the 
liquid solvent, there is no shifting towards the red, but on the contrary, 
towards the violet. In other instances even where the solvent liquid has 
no chemical action upon the dissolved substance, the whole character of 
the spectrum changes. A case in point is purpurin, which shows two 
beautiful absorption bands on F, the 6 group, and E, when dissolved in 
alcohol, but these bands are not seen in anaqueoussolution. Naphthalene 
red shows very different absorption spectra according as it is dissolved in 
alcohol, in water, in resin, or is solid, or used to colour paper. The curves 
representing the absorption in the several cases are different. Coloured 
gelatine behaves in a similar manner to the solid substance. 
Ueber die Verschiedenheit der Absorptionsspectra eines und 
desselben Stoffes.2 By HERMANN W. VOGEL. 
He refers to the researches on uranium salts made by Morton and 
Carrington Bolton, and gives the spectra of a number of inorganic 
coloured substances, 
Ueber die Verschiedenheit der Absorptionsspectra eines und 
desselben Stoffes.2 By HERMANN W. VOGEL. 
The substances examined were corallin and fuchsin in alcohol, water, 
and in the solid state, and the absorption bands were found to be the 
same in the solution, and but slightly shifted towards the less refrangible 
end according to Kundt’s Jaw. Curves are shown in the original paper. 
The solid substances showed somewhat different bands from the solutions, 
not so strong in the case of fuchsin, and lying nearer the green. He 
examined also indigo vapour in thick and thin layers, in the solid state, 
and in solution. He compared the spectrum with that of anilin-blue in 
water and alcohol, cyanine, and methyl-violet both solid and dissolved 
in alcohol. 
_ He dissolved purpurin in carbon disulphide, but could not see he 
bands described by Stokes.‘ 
The following conciusions were drawn from Vogel’s work : 
1. There is a remarkable difference between the spectra of a single 
substance in the solid, in the liquid or dissolved, and in the gaseous 
1 Ber. vol. ii. p. 622, 1878. 
* Ber. vol. ii, p. 913, 1878. 
* Ber. vol. ii. p. 1363, ‘ Absorptionsspectra organischer Kérper,’ 1878. 
* J, Chem. Soe. vol. xii. p. 21. 
