View report page

32
works of art of great value, are all articles difficult to treat
without injuring materially their value.
The strong assertions that have been made relating to
the harmlessness of formic aldehyde, seemed to show that
it might supplement or replace our sulphur process, and be
an especially valuable agent in those cases where, from the
intrinsic value or the delicate nature of the articles, it was
only possible to fumigate.
On Monday, the 12th April, the two top rooms of the
Shelter at the stone yard were prepared. Both rooms are
similar in construction, both having two windows, and both
having a fireplace in the same relative position.*
In each of these rooms were placed, on little bits of
linen, four cultures of diphtheria in gelatin, four of the
typhoid bacillus, four of the tubercle bacillus, and four of
anthrax. To judge of the damage to colours, if any,
unglazed paper was stained in the laboratory with aniline
dyes of known composition, viz., Orange 2 R., Rhodamine,
Mauve 5 B extra, and also some paper was stained with
Indigo-carmine, giving a light green tint.
The agent of the only autoclave for the production of
formic aldehyde at present in the market, attended and
evolved the gas in one of the rooms.
The apparatus for the evolution of formic aldehyde
consists of an autoclave, which will stand a high pressure ;
it is provided with a pressure gauge and a thermometer.
The chloride of calcium, saturated with the gas, is poured in a
silvered receiver, and a Swedish petroleum lamp is placed
underneath and lit. When the pressure gauge shows a
pressure of 40 lbs., then the gas is turned on and escapes
through a very fine copper tube.
The apparatus is usually placed outside the chamber
to be disinfected, and the copper tube is thrust through the
keyhole. It took pretty well an hour for the pressure to
get up to 40 lbs., and then the valve was turned on and the
*The Sulphured room has a cube of 1073 H. feet, the room tested
with Aldehyde, 1315.0 cubic feet.