VENTILATION. 
637 
and replace that which will be fast making its escape through 
the openings in the ridge. 
When a stable is newly erected this would admit of easy 
construction, otherwise the shafts w r ould have to be made in 
a similar way to those in one of the stables of the 16th 
Lancers, but brought down below the manger instead of 
terminating at the ceiling. Should the horses’ heads stand 
towards the centre of the building, without any other party 
wall, then I should suggest that they be constructed in the 
side walls. 
By these means, in a given area, I believe the noxious 
matters would be carried away, and a due supply of fresh 
air admitted. 
There are, however, times and seasons when any system of 
ventilation that we may adopt ceases to act, and air cannot 
be supplied without other adventitious aids. This is well 
known in mining districts, and what they call a “ fight;” 
which prevents the men from working, and obliges them to 
light fires in the main shafts. We should simply say the 
ventilation was stagnant. 
A similar result will explain several important facts ascer¬ 
tained by our president during a series of experiments 
carried out under his direction by First-class Veterinary 
Surgeon Collins. 
By their kindness I am enabled to show you a copy of 
them on this sheet of paper, and whilst you will find cir¬ 
cumstances detailed that in the perusal will strike your 
attention, you will also see how the different descriptions of 
ventilation seemed at certain periods to be passive, and at 
others acting in a contrary direction to what might have 
been anticipated. The whole tending to show that in those 
stables there is not sufficient area, that the intermural venti¬ 
lation is deficient in capacity, and is, from construction, not 
self-acting, but requires the aid of open doors and windows, 
and that the whole require what may be termed a circulatory 
medium. 
There is one circumstance connected with these experi¬ 
ments to which I wish particularly to direct your attention. 
If you will compare the differences of temperature in the 
three troop stables mentioned, viz., The troop stable with the 
ordinary ventilation; 2. The troop stable with the eight 
ventilators; 3. The troop stable with two roof ventilators; 
you will see that in some instances there is no difference in 
the temperature between them, and in others a difference of 
three or four degrees. 
This can only be accounted for by its bearing out the 
