intended for the Conveyance of Fresh Provisions. 763 
Fig 3. — End elevation of Waggon 
slmcing Filter -box open. 
Fig. 4. — Section through middle 
of Waggon. 
shows the longitudinal section, that the pipe which conveys the 
air from the filter-box is placed on an incline, so that the con- 
densed moisture runs back into the trough alread}' described. 
The air, on its return journey, passes into a drying chamber, 
shown at d, Fig. 2, filled with chloride of calcium. Any 
moisture which has escaped the condensing influence of the 
ice is here absorbed. The air thus dried and cooled finds 
its way into the meat-chamber by a number of holes in the 
sides of the drying chamber ; being dry and cold it is heavy, 
and as it falls gives up some of its cold, or rather absorbs some 
of the heat of the meat. This causes the air to rise, and when 
it impinges on the sides of the ice-chamber, all moisture taken 
up is condensed, and escapes by channels provided for the pur- 
pose. The air again descends, and then it passes through the 
chamber by a series of fallings and risings until it reaches an 
aperture at the bottom of the opposite end, which communicates 
with an external tube, which leads up to the roof and terminates 
in a revolving cowl. The action of the air is partly illustrated 
by the direction of the arrows in Fig. 2. Either wind or the 
motion of the train causes the cowl to revolve ; and even with- 
out this the higher temperature of the external tube w ould cause 
the cold air to rush out. Thus a thorough circulation of air is 
secured. 
Across the van are nine iron beams, made of two bars placed 
with a space between, through which the hooks slide. The 
chamber is made, as far as possible, air-tight, the doors being 
closed upon india-rubber linings. Colonel Mann is not an advo- 
cate for a very low temperature. He considers the great point 
