VENTILA TION. 6$ 



serviceable laid in this way for the roofs of smithies, as the 

 smoke also quickly passes through the interstices ; and in 

 washers' rooms and where a copper is used, the steam passes 

 rapidly away. 



Fig. 36. Fig. 37. 



In crowded localities, where structural arrangements render Down-cast 

 it impossible to obtain a supply of air direct through an external ventilation, 

 wall, it is necessary to use a down-cast ventilator, by means of 

 which the fresh air is driven down a vertical shaft into the 

 stable ; an arrangement of this kind, by Messrs. Boyle, is illus- 

 trated by Fig. 37. It is constructed on the principle of a wind- 

 sail, and the shaft can be recessed in the wall as a down-pipe, 

 or the ventilator affixed at the eaves, or, in a more ornamental 

 form, on the ridge of the roof ; or the extraction and supply 

 shafts could be carried up in one stack together with the flue 

 of the harness-room boiler, from which pipes for warming 

 the stable and coach-house are fed, and the whole of the 

 mechanical and automatic arrangements have one centre of 

 operation. 



It is a good plan, when there is an absence of through Through ven- 

 ventilation, to create a subsidiary circulation, by leaving a space ^i^^tion. 

 of about 4 inches between each partition and the wall -, this 

 would be kept up, without reaching the horse in the form of 

 a draught. Cavalry stables, built as a rule to accommodate 

 14 or 16 horses, with a couple of spare stalls in each stable, 

 have usually a space under the manger passing through the 

 partitions, and running from end to end of the stable, as shown 

 in Fig. 7, Plate 19, with a space also for ventilation below the 

 partition. The latter provision is considered by many as a 



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