476 
Covered Cattle Yards. 
seen a cheap and simple appliance used to obviate this occa- 
sional inconvenience — viz., pieces of half-inch board, about the 
width of the opening, suspended from the eaves between the 
piers by pieces of light chain. They are dropped when a storm 
occurs, and afford very effectual protection, and are readily looped 
up again out of the way when it abates. Seldom more than 
one side of the yard needs protection in this way at one time. 
Fig. 2 shows an ordinary queen-post truss, strong enough 
to carry a covering of slates or tiles. To get a ventilating 
opening high up in the roof, the queen posts are lengthened as 
shown, the clear space of a foot or fifteen inches thus obtained 
inducing a free current of air across the yard, and through its 
entire length, without any draught being felt below. The 
cm-rents from the gables are obtained, as shown in Fig. 1, by- 
leaving openings in them at the same level as the break in the 
Fig. 2. — Section of Hoof showing the late Sir II. 31. Thompson's 
Mode of Ventilation, covered with Slates or Tiles. 
roof and eaves openings. The spars on the upper part of the 
roof overhang the lower, and thus exclude rain and snow. 
The above embodies the principle of " roof ventilation " re- 
ferred to, of which the late inventor said that, " until he was 
better informed, he would take leave to call perfect." After many 
years of experience in the construction of Covered Yards, I have 
no hesitation in endorsing his assertion, and in no instance 
where it has been adhered to have I seen anything but the most 
complete success. 
I will now endeavour to set out the cost of the roof shown 
by Figs. 1 and 2, covered with slates laid in the ordinary way, 
and also covered with pantiles. 
Quantities and Prices of a Slated Roof on Sir H. M. Tliompsons 
Principle of Ventilation. 
Fig. 2.— (Close Slated). Fold Yard, 60' 0" x 45' 0" (inside). 
Yaiils Feet * '• '' 
218 run 0" x 3" framed tiebeams . . . . @ /6J 6 14 4 
524 „ 7" x 2£" framed ticbeams aud rafters and 
king posts „ /4i 9 16 ( 
