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from the animals causing displacement of the lower air which, when 

 warmed, will ascend and be replaced by cool, fresh air entering by 

 ' A ' or ' B ' or by both or numerous similar openings. 



The impure air leaves the stable by outlet ' D.' 



O C are windows hinged at the bottom and held in position by 

 small chains from a to b. The windows may be of any desired 

 width or height. If very high it is advisable to have the lower half 

 stationary and the upper hinged thereto as in B. 



The outlet D E F for such a stable as mentioned, if single, 

 should be about two feet sqmare. If it is preferred to have two 

 outlets, as is probably somewhat better, then each outlet should be 

 1^ feet square. This outlet pipe D E F may be in the centre or 

 to one side. So far as satisfactory working is concerned, I may say 

 that we have had almost equally good results when the pipe took the 

 courses D E F, D E E' F' or D' E' F' provided always that the out- 

 let F or F' was 2 or 3 feet higher than H the apex of the roof. To 

 prevent in some measure the inflow of snow or rain, a cap G should 

 be constructed over the outlet pipe. If conveniently situated, D 

 might serve as an opening through which to drop bedding or feed. 



The amount of air to escape through the outlet is controlled 

 by the trap T which may be regulated by cords descending into the 

 stable. 



SYSTEM OF VENTILATION ' C/ THE RUTHERFORD SYSTEM. 



This system is no doubt fairly well known to most readers, but 

 a few descriptive paragraphs will probably not be out of place. It 

 is the system most commonly used here for the reason that it has 

 proven to be most simple of manipulation and affords the least 

 opportunity of being badly worked or blocked by cattlemen unwisely 

 anxious as to the comfort of their charges. 



This system requires that the air enter at or near the floor level. 

 The best plan of bringing it in is probably as shown on the left 

 hand side in the diagram where the single-headed arrows indicate 

 the entrance of the air and its passage through A C B under the 

 wall. When the air current enters the stable it has an upward 

 direction, which it retains in some degree, but, once free from the 

 confining passage, it spreads and takes usually the course indicated 

 by the single-headed arrow. 



