IMPROVEMENTS IN TREATING WOOD FOR ITS PRESERVATION AND INCOMBUSTIBILITY
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by William Edward Gedge at the
Office of the Commissioners of Patents, with his Petition, on the
11th June 1875.-A communication from abroad by Alphonse
Frédéric Richard, of Dax (Landes), France, Engineer.
I, WILLIAM EDWARD GEDGE, of No. 11, Wellington Street, Strand,
in the County of Middlesex, Patent Agent, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN TREATING WOOD FOR ITS
PRESERVATION AND INCOMBUSTIBILITY," a communication to me from abroad
by Alphonse Frédéric Richard, of Dax (Landes), France, Engineer, to
be as follows:-
This Invention relates to the preservation and incombustibility of
wood by the aid of crystallized chloride of sodium in solution in water,
at between 6 and 24 degrees by Beaumé's aerometer, and of a solution of
chloride of sodium and alum at between 4 and 27 degrees, either mixed
in variable proportions or employed separately.

page_text: stances, or solutions less efficacious and more costly, of the same or a
different nature hitherto used for the preservation of wood.
2°. The substitution of a mixture of chloride of sodium and alum in
variable proportions in solution at the above-mentioned degrees, or the
use of one of these two bodies in solution for the preservation and
incombustibility of wood.
After eighteen years of study and experiment the Inventor of these
improvements has discovered that chloride of sodium in the state of
refined salt or perfectly crystallized and dissolved in water, between
6 and 24° by Beaumé's aerometer, is the best and cheapest preservative of
ligneous substances. He has found that wood impregnated with a
solution of less than 6 degrees is not preserved from destruction by
general causes, but that, according to the purpose for which the wood is
intended, an injection between 6 and 24 degrees preserved it from every
attack. Further his experiments have proved that if the solution
exceeds 24 degrees by this aerometer, a useless increase of weight has
been given to the wood and an excess of material used in pure waste,
and that even at 20° woods are safe from all causes of decay and are
rendered incombustible. At 10 degrees no insect or perforating or
boring animal of whatever kind, whether land or marine, such as the
capricorn beetle, the tenebrio, or others of the same order, such as
teredos, can no longer attack it; therefore the solutions under 6 degrees
and those exceeding 24°, as well as those termed saturated or con-
centrated, that is to say, which can no longer dissolve a salt of the same
nature, and those not coming directly from solutions of crystals of
chloride of sodium, are not claimed by the Inventor as regards the use
of chloride of sodium alone, but those prepared as aforesaid between
6° and 24 degrees inclusively are absolutely claimed as of this Invention.
The application of this Invention extends to all woods to whatever
species they belong, to protect them from all the usual causes of
destruction, from combustibility, from the attack of larvae, nymphae,
land and marine boring animals, whether they be used in railway
sleepers, telegraph posts, mining struts or uprights for land or sea
works, fences, etc., etc., and whatever may be the origin of the chloride
of sodium used in the solution.
The Inventor insists particularly upon the use of chloride of sodium,

page_text: say, as much as it can be obtained manufactured cheaply in salt pits
and marshes, but always in the state of crystals, which are afterwards
dissolved in the graduated proportions above indicated, this being in
order to avoid as much as possible the presence of hygrometric salts,
such as chloride of magnesium, sulphate of magnesia, chloride of
potassium, etc., which are always associated with chloride of sodium in
its natural state, whether in the more or less condensed waters of the
sea, in rock salt, in salt springs, or in solutions of rock salt, and which
separate from the chloride of sodium only when it is crystallized, and
that they are left abandoned in the liquid, the residuum of the
evaporation commonly known as mother water. The parasitical or
foreign salts by their hygrometric properties invite atmospheric humidity,
which added to their inherent causes of deliquescence, thus become by
causing the melting of the chloride of sodium an element adverse
to the principle of preservation, that is to say, that they produce in
the heart of the wood an opposite effect to that which it is sought to
obtain. The long and frequent experiments made by the Inventor of
this process have permitted him to avoid this, and the result of his
process is that while giving to the wood a greater density he does not
increase its weight, excepting within absolutely necessary limits, and
that it remains dry, withdrawn as it is from the atmospheric influences
the action of which is so preceptible upon the deliquescent salts which
would be introduced into it with the chloride of sodium, if solutions
were employed other than those indicated by the above formula. In
some cases however I may render wood incombustible by the use of
solutions of chloride of sodium other than given in the said formula,
whether in graduation, composition, and from whatever source derived.