420 Dr. Gladstone on the Colour of Salts in Solution, 
matic spectrum shows the ulternate bands of light and darkness 
due to the permanganic acid; but I did not recognize those due 
to uranium in the blue space. This, however, is not to be won« 
dered at, since the permanganaies admit very little blue light, 
and the uranium bands never show themselves till the light has 
traversed a considerable amount of salt. See figs. 2 and 3. 
CARBAZOTATES. 
Carbazotic acid gives a prismatic spectrum almost identical 
with that of chromic acid, but the line of distinction between 
the transmitted and the absorbed portions is about midway be- 
tween 6 and F. 
Carbazotate of Copper is a yellow sait, but its spectrum differs 
from that of carbazotie acid by the gradual absorption of the 
red ray—the universal effect of copper in solution. 
Haloid Salts, 
Chlorine, bromine, and iodine are, as all know, highly-coloured 
bodies ; and their solutions in water are also coloured. Yet the 
acids which result from their combinations with hydrogen are 
colourless ; and their compounds with most metals, including all 
those of the alkalies and earths, are colourless likewise, whether 
in the solid or the dissolved condition. Yet, as will be seen 
from the following observations, the peculiar effect exerted on 
light by the dissolved halogen itself appears also in its compounds 
with gold, platinum, and palladium: it appears, too, in its com- 
pounds with copper, nickel, and analogous metals; but in these 
cases only when the solution is very strong, the chromatic effect 
of the halogen wholly disappearing as water is added. 
BROMIDES. 
Bromine-water is red, and gives the prismatic appearance of 
fig. 13. The light transmitted near F is very dull. 
Terbromide of Gold is intensely red in solution, and gives a 
spectrum identical with that of bromine. On comparing fig. 15, 
it will be seen that a compound of gold with a colourless acid 
transmits all the rays transmissible by bromine-water. The gold 
salt figured is the nitrate. 
Bibromide of Platinum is intensely red, and likewise gives a 
spectrum identical with that of bromine. Fig. 16 will show 
that the remark made above in reference to the gold salt, applies 
here likewise. 
Bromide of Palladium and Potassium also gives the ordinary 
bromine spectrum. 
Bromide of Copper gives a saturated solution of a deep green 
colour; it transmits the spectrum represented in fig. 17, which 
