Letter on Covered Yards. 225 



reduced in size. In lately erecting a new set of buildings for 

 a farm of about 230 acres I found that co veering a farmyard 

 of 90 ft. by 55 ft. enabled me so to alter the arrangement of 

 the other buildings that, whilst giving entire satisfaction to 

 the tenant, the cost of the whole building was not sensibly 

 increased. 



" The chief value of my plan for roofing farmyards (described 

 by Mr. Moscrop) consists in the mode of obtaining a large pro- 

 portion of light without windows, ventilation without draught, 

 and both one and the other without expense. The principle of 

 ventilation is an entirely new one, and opposed to the general 

 theory on the subject. It is to admit the bulk of the ventilation 

 from above instead of below, and to secure a sufficient change of 

 air by having an uniform width of opening all round the upper 

 roof, so that there is always a current across the upper part of the 

 building though unfelt below. A small but sufficient opening 

 is left just above the heads of the animals to prevent any stagna- 

 tion taking place there. To any one who will take the trouble 

 of visiting one of my yards so constructed, I will undertake to 

 prove that this principle secures to its occupants complete 

 shelter without draught or smell, and a temperature scarcely 

 above that of the external air, which, until better informed, I 

 shall venture to call perfect ventilation. 



"I am, my dear Sir, yours faithfully, 



" H. S, Thompson. 



« Kirhy Hall, Feb., 1865." 



VOL. I. — S. S. 



