MISCELLANY. 
155 
usual method of employing the hop is volatilized for the greater part, 
may be obtained by distillation with water; 1 cwt. of hops would af- 
ford 3 oz. If, then, in brewing, extract were to be employed instead of 
hops, and the oil added when the beer is filled into the fermenting vats, 
the brewer would save all the expense of store-room for hops, avoid all 
the risks of the hop trade, could not easly be cheated, would be able 
to determine with greater certainty the quantities necessary to be added, 
and would require less hops, from the saving effected in the quantity of 
oil. The expense of obtaining the extract and oil from I cwt. of hops 
would not amount to any great deal, and by this a fourth of the hops 
would be saved on account of the oil ; so that when the price of hops 
stood at 120 florins per cwt. there would be a clear saving of 25 florins 
on the hops alone. A butt of beer would require about 2 oz. of extract 
and 11 grs. of oil. — Polytech. Central Blalt. 
[Another advantage of this extract, should it be found to answer, 
would be that the English brewer might import extract from America, 
from which country it is impossible to import hops, owing to their 
bulk. — Chem. Gaz.] 
Preparation of the Red Iodide of Mercury {Iodine lied) as a Paint. — 
M. Heller recommends the following method for obtaining a good iodine 
red. Commercial crystallized iodide of mercury is pounded and dis- 
solved in a boiling solution of sal-ammoniac (1 part of sal-ammoniac 
to 1| water). The iodide of mercury is conveyed into the boiling so- 
lution as long as any dissolves ; the hot solution is then decanted and 
allowed to ctoo], upon which the iodide of mercury again separates. It 
is deposited in - very beautiful purple-red crystals on the sides of the 
glass. Frequently these crystals appear at first of a pale yellow, ow- 
ing to the dimorphism of this salt ; but soon after the cooling of the 
liquid they become as beautifully red as those which directly separate 
of this colour. If the solution of sal-ammoniac was too concentrated, 
the sal-ammoniac is frequently deposited in white crystals along with 
the red ones ; this does no harm, as they may easily be separated by 
washing with water, to which they dissolve, while the latter are insolu- 
ble. When the cold liquid has been allowed to stand for half a day, 
the separation of crystals has terminated ; the liquid is then poured off, 
the crystals are washed, separated by means of a glass rod from the 
sides of the vessel, and dried. They are not pulverized, but are pre- 
served whole, and whenever wanted for use a small quantity is ground up 
with gum or oil. The colour of the crystals is net-so yellowish-red as 
the commercial powder, the well-known iodine-red, but more of a pur- 
ple-violet. The bright red colour is acquired when the crystals are re- 
