4 CHAPTER 1. 



indraught will occur again. Hence the unpleasant sensation of cold 

 draughts coming down suddenly on the head, so often complained of in 

 rooms ventilated only from above. 



To provide against any such sudden change in the direction of the 

 current it is necessary to admit by another and lower series of apertures 

 a certain proportion of the fresh air required. 



It is not necessary that the lower apertures should be large enough to 

 admit a volume of air equal to that which is escaping above, because, if 

 the upper apertures are properly constructed, a considerable proportion 

 of air will be constantly and regularly not in sudden draughts entering 

 on the windward side, whilst the foul air escapes on the leeward side. 

 In addition to which a certain amount of air comes in through the 

 windows and under the doors, even though closed. 



There is, however, confessedly great difficulty in arranging apertures 

 for the admission of fresh air without causing an unpleasant draught in 

 some portion of the room or stable. In this lies the more difficult and 

 more neglected part of ventilation. No one likes the sensation of a cold 

 draught on their own persons, and horses also appear to dislike it almost 

 as much as human beings. 



It is well, however, to remember that horses, in this respect, unlike 

 men, rarely suffer in health from cold, unless they are heated at the 

 time, and excepting also those doing very fast work, the pores of whose 

 skins are consequently very open. Their food, however, goes less far, 

 their coats become less sleek, and the highest development of condition 

 cannot be attained when the animals are subjected to such discomforts. 



9. Amount of cubical space required by horses in stables. 



It has not yet been ascertained how much, or rather what is the 

 minimum quantity of fresh air required by horses in stables. In a state 

 of nature the horse, we know, enjoys perfect freedom of air and exercise. 

 He is, moreover, constantly exposed to all the vicissitudes of weather and 

 climate, for he does not, like many other animals, make cover or shelter 

 for himself. A " mare's nest " has become a proverb. 



We may, therefore, assume that in the domesticated state he ought to 

 have an abundant supply of fresh air, with regular exercise ; and further, 

 that he is not likely to suffer from any moderate amount of cold, although 

 no doubt the increased action of the pores of the skin, which results 

 from fast work and grooming, creates an increased degree of susceptibility 

 in these respects. 



Unfortunately we have but few statistics to guide us as to the quantity 

 of air required by horses iii stables. Some approximate idea may, how- 

 ever, perhaps be gathered from a comparison with that required for 

 human beings. 



The Army Sanitary Commission, after much investigation, have 

 recommended that a minimum space of 600 cubic feet should be allowed 

 for each soldier in a barrack room. Now, assuming that the capacity of 

 the lungs of a horse is six times greater than that of a man, we might 



