ELEVENTH ANNUAL YEAR BOOK — PART IV. 121 



tern of ventilation, maintains that sixteen parts are not too many. It is 

 hoped that experiments will be conducted which will establish a standard 

 of ventilation. 



The dilution of air may be secured by four different means: 



1. The process of diffusion. 



2. The action of winds. 



3. The difference in weight of masses of air of unequal temperature. 

 4.. Mechanical means. 



The first of these is made use of in the so-called cheesecloth window 

 ventilators. The observations of the speaker and the recent tests of the 

 Ontario Agricultural College, would both indicate that this is in no 

 sense a true system of ventilation. 



The action of the winds is made use of by means of the so-called Sher- 

 ingham windows — windows that drop back into the building between 

 cheeks, providing an opening at the top through which a current of air 

 may pass. Cowls or cupolas are designed to assist in the aspirating effect 

 of the winds in drawing foul air from the building. At best, the effect 

 of the wind is unreliable for ventilation because it is irregular. 



The heating of the air and its consequent expansion is the most suc- 

 cessful agent used at the present time to produce ventilation. This is ex- 

 emplified by the King system of ventilation. Long flues are provided 

 which lead from near the floor to the highest part of the building. In the 

 speaker's opinion, this is the most successful system in use. The success 

 of the system depend upon making the barn warm, the wall air tight, and 

 the flues large and straight. 



Mechanical or forced ventilation has not been used to any appreciable 

 extent in barn ventilation, but time will see its general introduction. It 

 is a positive means of ventilation. All the other means mentioned vary 

 so much with atmospheric conditions. There was a time when all build- 

 ings were ventilated by other means, but the modern structure has the 

 mechanical, the positive means of ventilation. 



The main difficulty lies in supplying power to operate the fan or pump 

 forcing the air into or from the building. The amount of power required 

 is extremely small, but it must be continually in operation. Time will, 

 however, solve the problem. 



One striking thing about farm building construction in the past is that 

 very little thought has been given to the matter of permanency or 

 durability. The materials which have entered into the construction of 

 farm buildings have been largely those most available and those with 

 which the local mechanics were the most familiar. 



Cement is coming into more general use, and its use is to be highly 

 commended. Concrete construction, when properly handled, is as dur- 

 able as any material we now have. Its use in farm buildings is not well 

 worked out. The methods used in the large reinforced structures of the 

 city are not well adapted to use in the country. 



Another material which, no doubt, is worthy of a more extended use, 

 is vitrified clay building blocks. These introduce no new methods in 

 building construction, they are cheap, and are manufactured quite gener- 

 ally over the state. 



