Horses & stables / [Sir Frederic Wellington Fitzwygram].

  • Frederick Fitzwygram
Date:
1903
Catalogue details

Licence: In copyright

Credit: Horses & stables / [Sir Frederic Wellington Fitzwygram]. Source: Wellcome Collection.

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    words, of maintaining in their due proportion the proper constituents of the air. But in a closed room or stable there are no means by which she can carry on her restorative processes. Hence the need of ventilation. It is absolutely necessary to maintain or restore the proper constituents of the air, if we wish for health for ourselves or our horses. 6. Natural facilities for ventilation. Fortunately the peculiar properties, or rather the state of the gases which respectively constitute foul and pure air, afford great facilities for ventilation. Heat causes all matters to expand, some more and some less; but gases under the influence of heat expand very rapidly, and to a very great degree ; and as they expand, they of course become lighter. As a general rule, foul air in a stable is also heated air. It is only necessary to breathe on the hand to feel that our breath is generally wanner than the air. And besides the breath a certain amount of heat is given off from the bodies of all living animals. Carbonic acid gas, though at equal temperatures heavier, is nevertheless, when heated, as it is when first given off from the lungs, lighter than pure air. 7. Escape of foul air. The lightness of heated foul air at once affords the key for getting rid of it. It is only necessary to provide the means of exit in the highest part of the stable, and it will escape by its own inherent lightness. In fact we may get quit of it without any trouble. But, on the other hand, supposing that the foul air has no means of escape, what becomes of it ? It has risen to the top of the stable, because being heated it is lighter than the surrounding air. It will escape if it can, but if we deny it the opportunity of doing so, it must remain in the stable. It then gradually cools, and as it cools descends and becomes mingled with the air of the stable, and is in due course again presented to the nostrils to be breathed. Although we cannot see this movement of foul air in a room or stable, it may easily be shown by experiments with coloured gases. 8. How the place of the foul air is supplied. But supposing the foul air to have an exit above, how is its place, how is the vacancy caused by its escape, to be supplied by fresh air? If there are no apertures except those above, it is clear that by the continued ascent and escape of heated foul air a tendency to a vacuum will be created in the stable. It is well known that the pressure of the atmosphere is equal to 14 lbs. per square inch. When, then, even a tendency to a vacuum has been created, the pressure of the air on the outside is sufficient to overcome the upward current of heated air; and cold, fresh air will rush in at intervals to supply the vacancy. When the vacancy is supplied, the upward current and escape of heated air will be resumed until another tendency to a vacuum is created, when a similar
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