45 



to determine what system would produce the most uniform re- 

 sults in securing purity and dryness of atmosphere without draughts 

 and with the least amount of attention. The results of these inves- 

 tigations have been very profitable, inasmuch as a highly satisfactory 

 system has been arrived at, and one that is not protected by patent 

 rights. It is simple in principle and inexpensive to install. It is 

 automatic in action and only slightly influenced by the rate or 

 direction of the wind. 



The system was invented and put into operation by Dr. J. G. 

 Rutherford, for a number of years Dominion Veterinary Director 

 General and Live Stock Commissioner, and is known as the ' Ruther- 

 ford' system. The principle upon which it works is that of an 

 ordinary stove the stable corresponding to the stove, the animals 



The Rutherford system of ventilation. Cross section of barn showing principle of system and how it 

 may be installed in a building already constructed. 



to the fire, the inlets to the front damper and the outlets for the 

 foul air to the stove pipe or chimney. So long as the walls, windows 

 and doors are fairly close, the animals raise the temperature and cause 

 the ventilators to work, and this in proportion to the requirements. 

 The greater the number of animals and the closer the stable, .the 

 more rapidly will the system operate. And this is what is needed, 

 not only for purity of air, but for uniformity of temperature as well. 

 In a close stable, the degree of foulness of atmosphere corresponds 

 with the temperature, as both are directly influenced by the radiation 

 and breath from the stock. The air warmed by the stock naturally 



