NEW OR IMPROVED PROCESSES FOR DESTROYING NOXIOUS INSECTS OR VERMIN BY MEANS OF GASES AND VAPOURS ISSUED FROM CERTAIN SUBSTANCES
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by Isidor Loeser at the Office of
the Commissioners of Patents, with his Petition, on the 17th
December 1875.
I, ISIDOR LOESER, of the Firm of Loeser Brothers, of Trier, Prussia,
and actually at Paris, France, do hereby declare the nature of the said.
Invention for "NEW OR IMPROVED PROCESSES FOR DESTROYING NOXIOUS INSECTS
OR VERMIN BY MEANS OF GASES AND VAPOURS ISSUED FROM CERTAIN SUBSTANCES,"
to be as follows :-
My Invention relates to new or improved processes for destroying
noxious insects or vermin by means of gases or vapours.
The Invention consists in the employment for the above purpose of
sulphurous acid gas produced by the means or from the substance
herein-after referred to. This gas when produced by the simple combus-
tion of sulphur gives but imperfect results owing to the slowness with
which the latter burns, as is well known, the gas losing in tension in con-
sequence of its low temperature. It is moreover requisite that the
gases should displace the air to a certain extent.
From the foregoing it follows that the gases should be produced as
quickly as possible, and the temperature raised to the greatest extent
possible, as on these results alone depend their power of penetration.

page_text: According to my Invention the gases are produced at a pressure of
not less than two and a half atmospheres, and deducting air pressure
exert a force of one and a half atmospheres, whereby considerable
penetrative power is obtained. This elevated temperature is obtained
by adding to the sulphur when in a state of combustion one-fifth of its
volume of nitrate of potash (Ka O Na³). In this manner the combustion
of the sulphur is much more speedily effected, and a considerable
production of gases takes place at a high temperature. The combustion
is produced in a very simple manner by mixing sulphur and saltpetre
both in a pulverized condition (together with another substance herein-
after mentioned) in a box made of strong sheet iron, which is placed in
the middle of the room where the operation is to take place and the
contents then ignited. The other substance to be employed in addition
to the above mixture consists of indigo, which by distillation produces
an intense disgusting odour unbearable for all kinds of vermin. As the
indigo should not be consumed but only brought indirectly in contact
with the fire, I apply it in thick layers as a coating for the box
above mentioned.
The three substances above mentioned completely suffice for the
destruction of all kinds of insect life, but in order to destroy the eggs of
bugs another ingredient is added which will have the effect, viz., iadine
vapors of which are generated from finely ground iodides added to the
mixture during its combustion. The sulphurous acid gas quickly fills
all the spaces in the chamber, carrying with it the vapors of iodine
which have been found by experiment to corrode the outer integument
of the egg, and thus render the development of the same impossible.
The fumigating operation should be continued for five hours, during
which time the room is hermetically closed, after which the vapors lose
their tension by cooling, and in order to neutralize any gases remaining
in the chamber after the same has been ventilated for about half an
hour, ammonia may be sprinkled on the floor which quickly evaporates,
and forms with the remaining acid salts which are carried off by the air
current.