568 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[January 18, lfc73.. 
eerine in a very convenient and comparatively safe form. 
The observation that this substance could be exploded 
by detonation as readily (and even with greater cer¬ 
tainty) Rmixed with solid substances, which might be per¬ 
fectly inert in character, as when used in the liquid form, 
led him to the production of solid but plastic preparations 
of this substance, to which he gave the name of dynamite. 
The earliest of these supplied to the public, and the one 
which, in its present improved form, is superior to any 
other known nitro-glycerine preparation in point of 
safety in storage, consists of 75 parts of nitro-glyoerine 
held absorbed by 25 parts of a porous infusorial sili- 
cious earth, existing abundantly in Germany, and 
known as “ Kieselguhr.” This mixture was first sup¬ 
plied as a loose unctuous powder, from which the nitro¬ 
glycerine appeared to have a tendency to separate ; it 
is now converted by pressure into small cylindrical rolls 
or charges wrapped in parchment paper, from which, as 
far as the lecturer’s observation goes, the liquid does 
not appear liable to exudoj even upon prolonged expo¬ 
sure to elevated temperatures, though immersion in 
water will cause a separation of nitro-glycerine after 
some time. Many experiments were made in Paris 
during the siege, by MM. Girard, Millon, and Vogt, to 
ascertain what absorbent materials could be best ap¬ 
plied^ to the manufacture of dynamite, in the absence 
of Kieselguhr; precipitated silica or aluminia, sugar, 
and several other substances were found to be suitable 
media, but the material originally selected by Nobel was 
undoubtedly superior to all in its power of absorbing 
and retaining a very large amount of nitro-glycerine. 
The preparation of dynamite by Nobel was speedily 
followed by the production of other nitro-glycerine pre¬ 
parations, in some of which, such as Dualino, Horsley’s 
mining powder, and Glyoxiline, explosive substances 
are used as the media for absorbing nitro-glycerine. 
Nobel himself prepares a less violent form of dyna¬ 
mite by mixing nitro-glycerine in smaller pro¬ 
portions with powder, saltpetre, and resin or coal. 
A preparation which is perhaps intermediate in 
value between this and the “ Kieselguhr ” dynamite is 
manufactured by Messrs. Krebs, of Cologne, who have 
called it lithofracteur. As far as its composition has 
been made public, it is known to contain less nitro-gly- 
cerhm than Nobel's.ordinary dynamite; the absorbent 
material includes silicious earth and sand, saltpetre, coal, 
and sulphur. Some good practical experiments, made 
with this preparation at the Nantmawr and Breidden 
quarries, near Shrewsbury, satisfactorily demonstrated 
its safety in transport and use, when in its normal con¬ 
dition. In this, as in all other nitro-glycerine prepa¬ 
rations containing solid materials of inferior absorbent 
power to Kieselguhr, freedom from liability to a par¬ 
tial separation of the liquid can obviously be only se¬ 
emed at the sacrifice of explosive power, by reducin°* 
the proportion of the nitro-glycerine, and it is difficult 
to conceive that the consequent loss in power can be 
compensated for by introducing solid explosive materials 
less violent in their action than nitro-glycerine as com¬ 
ponents of the preparation. 
Nobel’s dynamite, though obviously inferior to the 
pure nitro-glycerine in explosive power, weight for 
weight, is still one of the most violent explosive agents 
now in practical use. In regard to power, it seems to 
be on an equality with compressed gun-cotton, and the 
results of experience in mines and quarries appear to 
wan ant the conclusion that in tne class of work where 
these agents can be applied to the greatest advantage, 
their power is about six times that of blasting powder? 
The advantages in point of saving of time and labour 
attained by the use of these violent explosive agents in 
tunnelling and other operations in hard rock are very 
important; they are also specially valuable in submarine 
operations, in the breaking up of large masses of rock or 
of large castings and forgings, in the rapid destruction of 
military works, bridges, and other structures, the clear¬ 
ing of forests, the removal of ice obstructions, etc.- 
Their special value is partly due to the comparatively 
small weight and bulk of the charges of gun-cotton or 
nitro-glycerine preparations required to perform the 
work (which in many instances could scarcely be accom¬ 
plished, even by extremely large quantities of gun¬ 
powder), and partly from the facility and expedition 
with which these explosives can be brought into opera¬ 
tion through the agency of detonation. Hard tamping 
or strong confinement is superfluous, and in many in¬ 
stances operations of demolition and disintegration may 
be effectually carried out, though with some waste of 
power, without any confinement wdiatever of the ex¬ 
plosive agent. 
Dynamite and similar nitro-glycerine preparations- 
possess two defects in common. One arises out of the 
poisonous nature of the liquid, which is readily absorbed 
into the system, producing severe headaches and other 
unpleasant effects, which, however, are said to diminish 
in severity and even to disappear by continued use of 
the material. Experience has scarcely been yet acquired 
regarding the ultimate influence upon the life of those- 
constantly engaged in manufacturing nitro-glycerine or 
using its preparations. The form in which dynamite is 
now furnished appears to reduce to a minimum the 
liability of those employing it to be injuriously affected.. 
The other defect arises out of the readiness with which 
nitro-glycerine freezes at a comparatively high temper¬ 
ature, especially when mixed with solid substances. Thu 
occurrence of several very serious accidents during 
manipulations with frozen nitro-glycerine, and the fact 
that the sensitiveness of a substance to explosion by a 
blow is in direct proportion to the rigidity of its particles,, 
favoured the conclusion that nitro -glycerine was specially 
dangerous when frozen; there is, however, no doubt that 
the substance is very much less sensitive to explosion by 
blow or concussion in that state—a fact which must be 
due to the greater expenditure of heat requisite for con¬ 
version of the solid than of the liquid into gas. The 
accidents with frozen nitro-glycerine and its preparations 
appear to have arisen from reckless handling in conse¬ 
quence of over-confidence in the safety of the material, 
and also from want of care or ignorance in carrying out 
the necessary operation of thawing the explosive agent 
before applying it in the usual manner. The necessity 
for thawing dynamite and similar preparations, which 
remain frozen even at 50° Fah., is a serious inconve¬ 
nience, which further experiment in the use and pro¬ 
perties of these materials may perhaps set aside. 
Plastic preparations of nitro-glycerine possess some 
advantages over compressed gun-cotton in several ordi¬ 
nary blasting operations. The application of a little 
pressure after the charge has been inserted will cause 
it to spread out and fill up any inequalities in the hole, 
and thus a larger charge may in some instances be em¬ 
ployed than if the rigid cylinders of compressed gun¬ 
cotton were used; the latter are also liable to become 
jammed or fixed when they are being pushed down a 
rugged or irregularly-shaped hole; if the miner then 
proceeds to force the charge home by powerful blows,, 
which, with reckless confidence engendered by the 
general safety of the material, he not unfrequently will, 
it may become ignited and must explode violently if' 
force is being applied at the instant of its igntion, as 
it is then in the position of a strongly-confined charge- 
Accidents in the charging of holes are obviously less- 
likely to occur with plastic materials. Dynamite has 
the additional advantage of being readily applicable in 
blast-holes from which water cannot be excluded, as the 
material resists penetration by water for a considerable 
period. To counterbalance these advantages, gun-cotton 
is perfectly innocuous, and its ready explosibility by de¬ 
tonation is not in any way affected by cold. When car¬ 
ried into the field for military purposes, compressed gun¬ 
cotton is very decidedly safer than nitro-glycerine pre¬ 
parations ; because if carts or packages containing the- 
