472 
Combating Lousiness 
allowed to enter the jacket, thereby warming the chamber and preventing 
undue condensation taking place inside; the air of the chamber is partly 
extracted by a steam jet and live steam at 20 lbs. pressure is allowed to 
enter it for 15 minutes. The steam is not allowed to escape, but a partial 
vacuum is again produced in the chamber and hot air, passing through a 
heated copper coil, combined with the heat from the jacket, dries the 
contents in about 15 minutes. As already indicated, the temperature of 
Fig. 24. Washington-Lyon Steam Disinfector. Size of chamber 2 x4 ft. Will admit a 
single mattress rolled up. This is “Model 13” as supplied to the War Office and referred 
to in table on p. 475. It is also made with a door at each end, or, when required, placed 
on a carriage. 
the steam in the jacket is higher than that within the chamber. The 
apparatus can be arranged to work as a current steam disinfector with 
saturated steam, at or slightly above atmospheric pressure, the pressure 
ranging from 1 to 20 lbs.; it can be used for hot-air disinfestation by 
heating the jacket only, steam not being admitted to the chamber. The 
steam may be derived from any suitable boiler (PI. XI, Fig. 7 and Text- 
fig. 24). 
