90 
VARIETIES. 
curred by pursuing these directions. This circumstance appears more re- 
markable, when we are aware that all extraneous application of heat is 
superfluous. Iodine and iron exert so powerful an affinity for each other in 
the presence of water, as to combine with the greatest facility, generating a 
large amount of sensible heat ; at the same time it is only necessary then to 
to bring their particles constantly in immediate contact with eacli other, to fulfil 
this end to our entire satisfaction, and for this purpose, two practical points 
must be attended to, first, to rotate the flask containing the mixed substances 
briskly and diligently for some moments in the hand, until the deep red 
color of the solution disappears, and is succeeded by its olive-green pellucid 
and normal one, which, when tested, should be perfectly permanent to the 
action of amidine. And, secondly, to break down the iron turnings as small 
as possible, carefully freed from any adhering oxide, by which means a 
greater superficial extent is exposed to chemical action, and thus ensure 
rapidity of combination more easily. 
By careful attention to these apparently insignificant points, the prepara- 
tion, in its first stage, will be divested of much of its practical difficulty, and 
rendered easier of execution, while risk from decomposition will be entirely 
obviated. Care should be taken to filter the solution (after testing it) into 
the saccharine mass, which preserves the neutral iodide of iron so far as to 
preclude the possibility of change from any subsequent heat that may be 
employed. — Pharmaceutical Journal, November \ % 1850. 
Red Color for Paper Hangings, &c— It is proposed to employ the red 
chloride of chromium for the production of an intense red-violet color, pos- 
sessing metallic lustre, proper for printing or staining paper. 
This product is prepared, as is well known, by passing a current of dry 
chlorine gas over a mixture of powdered charcoal and calcined oxide of 
chromium, inclosed in a glass tube. Attention must be especially given in 
this operation to the fact that, by reason of the difficulty of volatilization of 
the product, the chloride prepared by a first operation remains mixed with 
the powdered charcoal. It is therefore requisite to submit this mixture of 
charcoal and chloride of chromium to a second operation, taking care to 
cover the bottom only of the glass tube with it, in which case the product 
will be sublimed in the upper part of the tube. The heat of an Argand 
lamp, the flame of which is brought gradually upon the tube, will suffice 
for the formation of the chloride, which soon appears in the form of bril- 
liant micaceous peach-colored spangles. The chloride is then ground in a 
mortar, and thickened with a mucilage of gum. On being laid upon paper, 
it will display its original color, and will resist the action, not only of acids 
and alkalies, but also the direct action of the solar rays. — Ibid, June 1, 1850, 
from Nation's Journal, April, 1850. 
