Silver—pale gold.
Bismuth—some parts yellow, others not attacked.
Silver—blue, white, yellow-orange.
Bismuth—blue, yellow, orange.
In the action of iodine on bismuth, the influence of the physical condition of metallic surface is very manifest. The crystaline texture of this metal may be perceived, and the difference of its hardness admits, to a certain point, of being measured by the difference of the color of the films that are formed on various points; while most parts are yellow, there exist others of an angular outline which remain still unattacked; the same difference is remarked in the other stages of the combination.
It is impossible to estimate the affinity between mercury and iodine by means of the colored films, because, on combining, these two substances merely cause a dirty white appearance on the surface of the latter. Their combining affinity appears to be considerable, for when exposed together with silver the action produced with both was red at the edges, little altered in color; on the rest of its surface a dull white film, in the midst of which were seen several dark spots, where the metal was apparently unaltered.
Bromine with Mercury and Copper.
1st. Mercury—gold color.
" Copper slightly darkened.
2nd. Mercury—blue.
" Copper dark red.
3rd. Mercury—green on some parts.
" Copper white.
After this the copper underwent its usual changes of color on prolonging the action of the vapor of bromine, but the color of the mercury suffered no further change.
Chlorine with Mercury and Copper.
Mercury—a slight film.
Copper no alteration of color.
Mercury—deep gold color.
Copper deep red on some parts, blue on others.
Mercury—red tinged with blue.
Copper blue, white.
Mercury—blue.
Copper same as before.
"With respect to the bromide and chloride of mercury, it is necessary to view them obliquely in order to perceive all the changes of color they undergo; for if looked at perpendicularly, there is seen on both a dull uneven film of white which reflects none of the above colors: consequently, to avoid any error, the copper must be inspected under the same angle.