A NEW OR IMPROVED EXPLOSIVE COMPOUND
Year: 1876

page_text: LETTERS PATENT to Gustaf Fahnehjelm, of Stockholm, Sweden, for th
Invention of A NEW OR IMPROVED EXPLOSIVE COMPOUND."
66
DOLL
A
PROVISIONAL SPECIFICATION left by the said Gustaf Fahnehjelm at the
Office of the Commissioners of Patents on the 21st October 1876.
GUSTAF FAHNEHJELM, of Stockholm, Sweden.
COMPOUND."
"A NEW OR IMPROVED EXPLOSIVE
This compound has like most of the modern explosive compounds nitro-glycerine
as a chief ingredient, but is distinguished from them in that the second main
ingredient is wood charcoal. The wood charcoal serves not only to absorb and
retain the nitro-glycerine oil in a more complete manner than every other means,
but it also increases the explosive action considerably, inasmuch as the superfluous
hydrogen produced by the explosion is burnt to carbonic oxide or carbonic acid,
whereby the amount of gas is increased and a higher temperature is produced, thus
causing a much larger expansion of the gases of explosion. As the nitro-glycerine
however in order to be completely absorbed requires a much larger quantity of
carbon than the surplus hydrogen of the nitro-glycerine can oxidize, I add a
sufficient quantity of such salts, which by their detonation produce free hydrogen in
order that the combustion may be perfect.
The proportion of parts must be somewhat varied in this new or improved
compound which may be called new Sebastin, and the following have been found
suitable, viz. —
45 to 75 per cent. of nitro-glycerine.
15 to 30
"
5 to 25
1/2 to 5
1/2 to 5
"
"
"
of wood charcoal.
of nitrous or chlorous potass or natron.
of carbonic acid salts, and
of some neutral binding material to hold the com-
pound together and resist the influence of water.
The carbonic acid salts are only added in order to gain perfect security against
every appearance of free acid in the compound.
By experiments with this compound a greater explosive force and absence of
danger have been obtained than by any other nitro-glycerine compounds heretofore
applied.

page_text: SPECIFICATION filed in pursuance of the conditions of the Letters Patent, and
of of an Order of the Lord Chancellor, by the said Gustaf Fahnebjelm in the
Great Seal Patent Office on the 1st May 1877.
GUSTAF FAHNEHJELM, of Stockholm, Sweden. "A NEW OR IMPROVED EXPLOSIVE
COMPOUND."
In this new or improved compound nitro-glycerine forms the chief constituent
part as in the case of several other modern explosive compounds, the second main
ingredient is charcoal produced from a special wood, and selected and prepared in
such a manner as to be able to absorb and solidify the greatest possible quantity of
nitro-glycerine.
In order to render the combustion more complete and to augment the rapidity of
the explosion a small quantity of nitrate of potass or other suitable salt is added to
the mixture of the two ingredients above named.
I am aware of the existence of Patents for explosive compounds in which nitro-
glycerine and wood charcoal are mixed with explosive salts, and especially with
chlorate of potass, but in those compounds the salts are applied in large quantity
and serve as the chief base of the compound, while only a small proportion of nitro-
glycerine is added and only for the purpose of igniting and exploding the compound.
This new compound thus differs from the ordinary dynamite in which the nitro-
glycerine is absorbed by the infusorial carth, in that the solidification of the oil is
effected by the aid of an active base, namely, charcoal of a special kind, and it
differs from other explosives, firstly, by reason of the application of the charcoal of
a special kind, which is able to absorb from five to six times its weight of nitro-
glycerine; secondly, by reason of the proportions of the substances which will be
explained further on.
In the ordinary dynamite the infusorial earth cannot keep and retain the oil
absorbed under certain circumstances. When such a dynamite is exposed to changes
of temperature, and especially when it has become frozen, and then passes into the
pasty state again a part of the nitro-glycerine becomes separated from the mixture.
The danger resulting therefrom is not greatly to be feared if the nitro-glycerine is
absorbed by a charcoal of the kind used in the improved process here in question.
In order to produce a charcoal having the required qualities the carbonisation or
coking must be done in such a manner as to completely destroy the organic
substances, and to produce as porous a charcoal as possible. For this purpose I
select by preference young trees or striplings, or branches of poplar, hazelwood, or
aulder tree, and I burn them in an open fire.
When the wood has been consumed I do not put out the fire by means of water,
but I leave it to go out of itself. In this way I obtain a very inflammable and
very porous charcoal which can absorb more than five and approaching to six times
its weight of nitro-glycerine without any risk of the separation of the oil.
The charcoal is pulverized in a wooden mortar, but it should not be reduced to too
fine a powder, else it will not so completely absorb the nitro-glycerine.
The charcoal produced in the ordinary way or by closed fire is quite different as
regards absorbing power. Charcoal of fir tree may however be used and may
acquire nearly the same qualities, that is if charred a second time in a special oven.
By mixing the different kinds of charcoal a material may be obtained possessing
the required absorbing qualities, and an explosive compound may then be obtained
of the required power without loss of the necessary consistency, that is without
being too dry which is not desirable. The charcoal not only seves as the best
absorbent for the nitro-glycerine, but it plays also an important part in the com-
bustion. The nitro-glycerine in exploding decomposes into steam, carbonic acid,
nitrogen and oxygen. In the explosion of dynamite with inert base the oxygen
goes away without being utilized; but in the explosion of this new compound (the
new sebastin as I call it) a part of the absorbent charcoal is burnt by means of the
liberated oxygen, the quantity of gas is thus augmented, and also the developement

page_text: of heat, whereby again the tension of this gas is augmented. As however the
quantity of charcoal necessary for the complete absorption of the nitro-glycerine is
in all cases much larger than that which can reduce the excess oxygen produced at
the explosion into carbonic acid, I add to the compound a salt, which also by the
the combustion gives an excess amount of oxygen which may contribute to burn the
rest of the charcoal. For this purpose I use by preference nitrate of potass which
may be added without any risk, and which gives the explosive compound a very
much greater rapidity or vehemence and consequent force of explosion.
The composition of the new sebastin depends upon the cbjects for which it is to
be used, and the effects intended to be produced. The strongest compound (which
may be made without risk of the separation of the oil therefrom) may then be
composed as follows:-
No. 1.78 per cent. by weight of nitro-glycerine.
14
8
"
"
"
"
"
the wood charcoal.
nitrate of potass.
Another compound of less force may be compounded as follows:-
No. 2. 68 per cent. by weight of nitro-glycerine.
20
12
"7
"
"
>>
رو
"
the charcoal.
nitrate of potass.
Let the dynamic force of pure nitro-glycerine be represented by the number
2-884043,6, then the dynamic force of the new Sebastin, No. 1, as above will be
indicated by 2.416-575, and of the new Sebastin No. 2, by 1.933-079,4, while that
of dynamite No. 1 (consisting of 75 per cent. of nitro-glycerine, and 25 per cent. of
infusoral earth) will be presented by 1.674-694.
For the above qualities of new Sebastin the increased effect produced by the
greater rapidity of the explosion must be taken into account also. The increase has
not yet been measured, but is estimated at ten per cent.
The new Sebastin may also be compounded in other proportions of the constituent
parts, but the object being to produce explosive compounds of the greatest force
which it is possible to employ without danger, I only subjoin the following
proportions as margin or latitude :-
50 to 80 per cent. by weight of nitro-glycerine.
15 to 35
>>
"
32
5 to 20
"
"
"
the charcoal.
'nitrate of potass.
And having thus fully described and ascertained the nature of this Invention, and
the node of carrying the same into effect, I declare that I do not claim the com-
bination of nitro-glycerine and wood charcoal in general, but I claim,―
Firstly. The production of a solid compound of nitro-glycerine and a wood
charcoal prepared in the special mode or modes herein set forth, the nitro-glycerine
being the principal ingredient which is absorbed by the wood charcoal to the extent
of more than five and reaching nearly six times its weight without risk of this
compound parting with any of its oil as set forth.
Secondly. The addition to the said solidified nitro-glycerine of a quantity of
nitrate of potass or other suitable salt not exceeding twenty per cent. of the whole
mass for the purpose of rendering the combustion as complete as possible as
set forth.
In witness whereof, I, the said Gustaf Fahnebjelm, have hereunto set my hand
and seal, this Fifth day of April, in the year of our Lord 1877.