January 25, 1373.] 
THE PHARMACEUTIC A.L JOURNAL AND TRANSACTIONS. 
585 
tainly dissolves the oxide of mercury, but it re¬ 
quires a greater degree of heat than the pure acid to 
affect tlie solution, while at the same time some of 
the oxide is invariably reduced to the metallic state, 
owing to the presence of some readily oxidizable 
impurities in the acid, or 'perhaps due to the oxida¬ 
tion of the acid itself. The amount of reduction is 
in direct proportion to the degree of temperature 
employed, as might have been anticipated, and was 
proved by a number of experiments : 
192 grains of oxide of mercury, corresponding to 
177‘7 grains of metallic mercury, heated with ten 
times the weight of oleic acid, gave the following 
reductions:— 
At 300° F. amount of reduced Hg . 175 grains. 
At 280° F. „ „ . 152 „ 
At 212° F. „ „ . 09 „ 
At 200° F. „ „ . 35 
Between 200° and 180° F. the amount of reduction 
varied between 20 and 40 grains, according to shorter 
or longer exposure to heat; but I have been un¬ 
successful in effecting a solution unaccompanied by 
reduction. This makes it necessary to estimate the 
strength of each fresh lot of solution. 
The strength of the preparation as prescribed by 
different physicians has varied from twenty per cent, 
to two per cent, of oxide of mercury, with variable 
quantities of morphia ; but of late a uniform strength 
of six per cent, of oxide of mercury and two per 
cent, of morphia is deemed sufficient for most pur¬ 
poses, and the following is the process which I 
employ for its preparation :— 
Expose the commercial oleic acid to a temperature 
of 40-50° F., and express the liquid portion, which 
is oleic acid,deprived of the greater portion of the ac¬ 
companying solid acids. Take of oleic acid, prepared 
as above, 1530 grains; oxide of mercury, perfectly 
dry, 192 grains. Bub the oxide in a mortar with 
some of the oleic acid to a smooth paste; add the 
remainder of the acid; place the mortar on a water 
bath, and promote solution by frequently stirring, 
taking care not to allow the temperature to exceed 
20Cffi F. 
As soon as all the oxide has disappeared, or rather 
as soon as the undissolved residue is of a pure grey 
colour, remove the mortar from the water bath and 
allow it to stand for twenty-four hours. Then pour 
off the clear solution into a tared capsule ; wash the 
residue thoroughly with ether, and add the washing 
to the liquid in the capsule. Expose the latter to a 
very gentle heat, until all the ether has evaporated, 
and weigh. The residue, after being properly washed 
and carefully dried (without heat), may be weighed 
as metallic mercury, which is in practice sufficiently 
correct. 
Supposing the weight of the obtained solution to 
be 1098 grains and the weight of the reduced mercury 
to be thirty grains (assuming therefore that there 
has been no loss incurred during heating and during 
the subsequent washing of the residue, whilst in 
practice a small loss always occurs), we first calculate 
the amount of Hg0 2 , to which the thirty grains Hg 
correspond:— 
Hg HgO a 
200 : 30 = 210 : 324 
The solution, therefore, weighing 1098 grains, only 
contains 159'0 grains of Hg0 2 or 9 4 per cent. 
This solution is now to be reduced to the 
strength of six per cent, by the addition of more 
oleic acid, until it weighs 2000 grains, but we also 
want two per cent, of morphia. The balance want¬ 
ing (2000 — 1098 = 902 grains) is obtained by dis¬ 
solving fifty-three grains of morphia in 909 grains of 
oleic acid and adding it to the first obtained solution 
of 1098 grains, making a dark brownisli-red liquid, 
of sp. gr. 0’975 at 00° F, and containing six per 
cent. (159‘G grains) of Hg0 2 , and two per cent. (53 
grains) of morphia. 
It is scarcely ever used for the purpose of pro¬ 
ducing the constitutional effects of mercury, but 
rather as a resolvent for articular anchylosis, and it 
has produced excellent effects in cases of chronic- 
articular rheumatism and in gout, by removing the 
stiffness and producing flexibility of the joint. 
After writing the above the author succeeded im 
obtaining a sample of oleic acid, which dissolved the- 
oxide completely, and, if previously separated by- 
cooling from the solid acids, did not producethe least 
reduction. He also found that a much lower degree 
of heat was sufficient to effect solution (100°-180° 
F.). A lot of oxide of mercury mixed with half its- 
weight of carbonate was employed in a few instances, 
and gave even better results than the oxide alone. 
The resulting product, made with this kind of oleic 
acid, was of the consistence of thin cream and of a 
light brownish-yellow colour. 
A sample of the English oleic acid, expressly im¬ 
ported by a friend, gave invariably a greater or 
lesser reduction, and so did all the other varieties 
tried, with the exception of the last. 
THE MORE IMPORTANT SUBSTITUTES FOR. 
GUNPOWDER. 
BY F. A. ABEL, F.R.S.* 
[Continued from page 569.) 
Although gun-cotton and nitro-glycerine mixtures ’ 
possess very important advantages over gunpowder in 
all applications where suddenness and violence of action 
are desirable, there are some directions in which they 
do not possess superiority over powder, and others in 
which they cannot replace it, irrespectively of its appli¬ 
cations to projectile purposes. In soft rock, in earth 
mines, and in some blasting operations, when it is de¬ 
sired to displace large masses of earth, rock, or stone, the’ 
gradual action of gunpowder gives it decided supe¬ 
riority. The more violent explosive agents produce 
great local effects ; the rock, if hard, is much shattered 
near the charge, and is also rent and fissured to consi¬ 
derable distances, but the displacing effect is generally 
inferior to that produced by the equivalent of powder, 
and always very much so in earth or soft rock. Decided 
advantages have arisen from a judiciously-combined ap¬ 
plication of gunpowder and gun-cotton or dynamite, the 
more violent explosive agent being used to prepare the 
way for gunpowder, which is afterwards applied to the 
removal of the material shattered by the first sudden ex¬ 
plosion. 
The degree of safety with which explosive agents may 
be manufactured is an important question connected with 
their extensive application. The fact that the manufac - 
ture of gun-cotton as now carried on involves not the* 
slightest risk of explosion up to the final stage, when 
the material has to be dried, distinguishes it from most 
other explosive agents. In gunpo vvder-manufacture 
liability to explosion exists throughout all operations 
from the point when the ingredients are mixed, and with 
regard to nitro-glycerine it appears that up to the pre¬ 
sent time occasional severe accidents during manufacture- 
* Read at the Royal Institution of Great Britain, on 
Friday, May 17th, 1872. 
