Improvements in Explosive Compounds.
Year: 1889

page_text: Date of Application, 7th June, 1889
Complete Specification Left, 6th Mar., 1890-Accepted, 26th Apr., 1890
PROVISIONAL SPECIFICATION.
Improvements in Explosive Compounds.
I, WILLIAM BAXTER MCGAVIN, of Woodford Green, in the County of Essex,
IMPROVEMENTS
Gentleman, do hereby declare the nature of the said invention for
IN EXPLOSIVE COMPOUNDS" which invention has been communicated to me from
abroad by Ebenezer William McGavin, of Sydney, in the Colony of New South
Wales, to be as follows:-
According to this invention an improved explosive compound is prepared by
mixing pierate of potash, sawdust, nitrate of potash, nitrate of sodium and
sulphur.
The picrate of potash should be prepared as follows: Picric acid is dissolved in
boiling water and nitrate of potash in another portion of water, which should be
warm. These solutions while still warm are mixed, and the yellow picrate of
potash which is thereby precipitated is collected.
The freshly precipitated picrate of potash is then dissolved in boiling water and
the solution is caused to be absorbed by sawdust. The impregnated sawdust is
dried and powdered, nitrate of potash, nitrate of sodium and flour of sulphur
added, and the whole well mixed, and is then ready for use.
The powder may be used either as produced, that is in a state of fine division
or it may be granulated, or made into blocks, sticks, or bars as may be most
convenient for use.
In order to granulate it, the impregnated saw-dust should be taken before it is
dry and mixed with the other ingredients, and powdered or ground, care being
taken to keep it constantly and sufficiently moist.
The dough may then be granulated by passing it through sieves or otherwise,
or pressed or moulded into the shapes required.
The proportions of ingredients which I have hitherto found it most advantageous
nitrate of
to employ are approximately as follows: Picric acid 1 kilogramme ;
potash 2 kilogrammes.
Of the precipitated picrate of potash 1 kilogramme in 36 kilogrammes of water;
15 kilogrammes of sawdust.
Of the impregnated sawdust 10 kilogrammes, of nitrate of potash and nitrate
of sodium each 17 kilogrammes, and flour of sulphur 7 kilogrammes, but these
proportions or some of them admit of considerable variation and are not probably
those which further experiment may decide to be the best.
Dated the 30th day of July 1889.
NEWNHAM BROWNE,
Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Explosive Compounds.
I WILLIAM BAXTER MCGAVIN, of Woodford Green, in the County of Essex,
Gentleman, do hereby declare the nature of the said invention for "IMPROVEMENTS
IN EXPLOSIVE COMPOUNDS" which invention has been communicated to me from
abroad by Ebenezer William McGavin, of Sydney, in the Colony of New South
Wales, and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement:—
According to this Invention an improved explosive compound is prepared by
mixing picrate of potash, sawdust, nitrate of potash, nitrate of sodium and

page_text: The picrate of potash is prepared as follows:
One pound of the purest commercial or chemically pure crystalized picric acid
is dissolved in boiling filtered water, and in another vessel two pounds of purified
nitrate of potash are dissolved in warm filtered water, the two solutions whilst
still warm are mixed, whereby a yellow, precipitate is formed which is picrate of
potash.
The substance thus obtained is to be mixed with sawdust, nitrate of potash,
nitrate of sodium and flour of sulphur in the following manner and proportions.
Sawdust is next to be saturated with this precipitate in the following manner.
Take one pound of the above described freshly precipitated picrate of potash and
dissolve it in thirty pounds of boiling water, into which solution put fifteen
pounds of sawdust and when the sawdust has completely absorbed the liquid,
thoroughly dry it till every vestage of dampness has escaped.
This impregnated sawdust is to be mixed with the following ingredients vis ·
These ingredients are well mixed with the impregnated sawdust and the substance
is ready for use.
The sawdust before mentioned, preferably of hard wood, may be ground or
powdered wood, or ordinary saw dust, provided in either case that it and all the
other ingredients are reduced to a fine powder.
The product in its finished state should resemble meal or flour, but it may
however be granulated or made into small sticks or bars or be otherwise shaped
or moulded as next described in which state it is handier and more convenient
for use.
The process for granulating it or making it into moulded shapes or the like is
as follows:
After the sawdust has been impregnated as above described it is not allowed to
dry, but is mixed with the three last mentioned ingredients, viz, the nitrate of
potash, nitrate of sodium and flour of sulphur in a perfectly damp state, and it is
then either pounded for about an hour in a wooden trough, or ground in a mill
or the like.
During this process great care must be taken that the dough be kept sufficiently
damp that is to say, that it be not allowed to become anywise dry.
The dough having been thus pounded or ground, is then either granulated by
being passed through sieves, or pressed into sticks by means of a hand press, or
is otherwise shaped or moulded, and is then dried and ready for use.
The proportions above stated are those which have been found most advantageous,
but they admit of considerable variation, and are given by way of example and
in order that this invention may be fully understood, and are not intended to
limit the scope of the Invention to the exact proportions stated.
So far as I am aware my said explosive compound cannot be exploded by
percussion. The only method of exploding it known to 'me is to confine it, for
instance, as blasting powder is usually confined when it is stamped in a drill hole,
and to fire lit by means of an ordinary fuse in the same manner as common 'block
powder is fired.
Having now particularly described and ascertained the nature of the said Inven-
tion and in what manner the same is to be performed as communicated to.
me by my foreign Correspondent I declare that what I claim is.
4. The manufacture of an improved explosive compound of the materials and in the
manner substantially as hereinbefore described and set forth.
2. The production of an explosive compound by the combination of picrate of

page_text: potash with alkaline oxidizing substances such as nitrate of potash or soda together
with sulphur and powdered wood substantially as described.
3. The preparation of an explosive compound by the admixture of picrate of potash,
dissolved, and absorbed by sawdust or finely powdered wood, with nitrate of potash,
nitrate of soda, and sulphur, substantially as hereinbefore set forth.
4. The mixture in a dry state of sawdust when impregnated with picrate of potash
with nitrates of potash and soda and with sulphur and the preparation of the same for
the purpose of producing the improved explosive compound as described.
Dated the Sixth day of March 1890.
W. B. MCGAVIN.