MANAGEMENT OF LIGHT HORSES. l6l 



constitute foul and pure air, afford great facilities for ventila- 

 tion. 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 warmer than the air. The foul air being lighter 

 than the pure air, the former rises, and this of course suggests 

 that the most efficient method of getting rid of it is to provide 

 an outlet at the top of the stable where the foul air will 

 collect. In principle, therefore, it is easy enough to ventilate 

 a stable, but in practice difficulties often present themselves. 

 Some stables are low and have lofts over them, and when this 

 is the case the employment of louvre boards the best means 

 of ventilation is impossible. Amateur ventilation often takes 

 the form of knocking holes in the walls here and there, with 

 the result that the horse stands in a perpetual draught. The 

 owner knows that ingress must be provided for the fresh air, 

 and an exit for the foul air ; but in making one and the other 

 a draught is created, and this will also be the case when there 

 is also ventilation from above, for as soon as the foul air has 

 escaped the pure air will come in at the openings and draw 

 down on the unlucky horses below. 



In order, therefore, to get a properly ventilated stable it is 

 necessary to have apertures at the roof to allow the foul air to 

 escape, and openings lower down to permit of the ingress of 

 fresh air, and how to do this without at the same time creat- 

 ing a draught is one of the difficulties against which he who 

 constructs a stable has to contend ; it is far easier to provide 

 for the escape of the foul air than for the ingress of the fresh 

 supply. With the aid of professional advice it is a compara- 

 tively simple matter to have a properly ventilated stable 

 where space allows of the length, breadth, and height being 

 just what they should be ; but, when buildings of all sorts of 

 shapes and plans have to be occupied, the difficulties are 

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