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40
an ordinary steam boiler, but having an outer casing or jacket,
with a space between. Into this space steam is admitted at a pressure
of 25 lbs. on the square inch, which corresponds to a temperature of
about 264°. This is for the purpose of thoroughly drying and heating
the chamber and its contents. The truck containing the articles
to be disinfected is placed in the interior chamber, the large doors
being opened for the purpose. These are then closed hermetically,
steam is admitted, and the process of disinfection commences. The
pressure is about 20 lbs., so that the steam must penetrate any
mattress, bed, or article of furniture that may be under treatment,
and the temperature of 260°, which is the heat of steam at that
pressure, is rapidly communicated to articles in the Chamber. The
form of apparatus shown the Special Committee, though upon the
same principle as that shown on p. 7, varied somewhat in detail.
Instead of doors at each end, closed by screw gear, a single hinged
door, fastened by clamps, was used. The clamps have since been
modified, and are worked by means of vice handles instead of spanners,
thus much reducing the time required to open and close the doors
This, though a considerably less expensive plan, requires more labour,
and is used at Mr. Lyon's own works, as it suits his particular puposes
better, and he has always plenty of help available. At the time of our
visit a registering thermometer was placed in the centre of a hair mattress
before the chamber was closed. After a few minutes the steam was
shut off, but the thermometer at the top of the apparatus remained
stationary at 260°; and this was due to the outside jacket, the great
object of which is to prevent condensation of the steam within the
chamber, for if such were to take place the articles placed therein for
disinfection would become wetted and spoiled. After being thus
treated for about half an hour, the steam was blown off, the chamber
opened, and the goods removed. The thermometer placed in the
centre of the mattress registered 259°.
The difficulty experienced in bringing every portion of the objects to be disinfected to
the temperature needful for purification in the old fashioned heated chamber, involves the
employment of a dry heat often injurious to such of the materials as are subject to its
influence.
Bedding, Blankets, &c., are the highest out-comes of the ingenuity of man to check the
circulation of heated air from one side of the fabric or object to the other. A hot bottle
placed in a bed retains its heat for hours or days, and no one would expect to receive
much or any sensible warmth on the outside of a bed containing such bottle, and yet in
the gas or hot-air form of disinfecting oven generally used we expect heated air to
penetrate every portion of the objects when they are all folded together. We expect it
not only to dislodge the air entangled with them, but to part with its own sensible heat,
and move away to allow fresh portions of heated air, to complete the process; we even
employ the same gases, i.e., hot air and cold air, between which there must be but little