VENTILATION. 201 
plan is, perhaps, the best. In this a large tube of iron is made to descend 
from the apex of the roof to the stable ceiling; and being divided into 
four tubes by iron plates, which rise above the top, the wind always 
descends through one or two of these tubes whenever there is the slightest 
air moving. Unfortunately, however, it happens that when it is most 
wanted, it is totally inactive—namely, in the hot, calm days of summer. 
Ventilation is always easy enough when there is a wind blowing; and, 
indeed, the difficulty then is to moderate it; but it is when there is no air 
moving that stables become so hot and close. I have known these down- 
current tubes tried in all sorts of places, including stables, kennels, work- 
rooms, cigar-divans, &c.; but I have always found that, without the power 
of moderating the down-draught by closing-valves placed at the bottom 
of the tubes, they are not only useless in calm weather, but highly dan- 
gerous in a wind. Now, horses have not the sense to close valves, when 
a wind rises in the night, and grooms are absent from 8 o’clock p. w. till 
6 a.M., during which time a whole stableful of horses may be chilled fo an 
alarming extent. Hence, if adopted, I should never venture to leave 
these ventilators open during the night, and this would take away from 
their efficiency sufficiently to forbid their use. I greatly prefer the valvular 
window which I have described at page 197, for the introduction of air, 
and a plain ventilating shaft, such as I shall presently allude to, for car- 
rying off the foul air. Failing the window from any cause, nothing is 
better than a latticed ventilator, like the following, which should be fixed 
[lll 
in the head wall, or in either of the side walls, near the head. The louvres 
should be moveable, so as to moderate the draught; and the usual plan is 
to make them open and shut by pulling a cord. The price is, for the size 
twelve inches by eight, 9s. 6d., or fourteen inches by ten, 13s. 9d. A 
small ventilator is sometimes required, like one or other of the annexed, 
which may be fixed in any part of the stable where air is wanted. These 
also open and shut, but they require the hand itself, or some intermediate 
agent, such as a shovel-handle, and cannot be arranged to move by a cord. 
The usual prices are as follows :— 
8. d. 
Square, to openand shut. . . . . Qinches by 9 inches 4 0 
Ditto ditto . . + . . 12inches by 12 inches 6 G6 
Ditto ditto . .'. ; . 5 inches by 15 inches > Ow 
Oblong, to open and shut. . . . . 18inchesby 4}inches . . 3 0 
Ditto ditto . . . . . l6inchesby 4} inches . 4 °0 
Large Round, to open and shut . . 22 inches BOA gee elvan 06 
