478 
Covered Cattle Yards. 
It will be seen from sketches A and B that there is a free 
space for admission and emission of air between every slate, 
2^ inches wide by the thickness of the slate, which, in the aggre- 
gate's something very considerable, and, being distributed evenly 
over the whole roof, there are no draughts, and is another cheap 
way of getting roof ventilation. The weight being much less — 
something over one-fourth — than in ordinary slating, the roof- 
trusses may be placed farther apart, thus resulting in a less 
costly form of structure. 
Those who have yards covered in this way speak very 
favourably of them, and, as will be seen below, the cost is mode- 
rate, and leads one to think that, as the plan becomes better 
known, it will be more widely adopted. 
Quantities and Prices for Hoof covered with Oj>en Slating. 
Fold Yard GO' 0" x 45' 0" (inside). 
Yards Feet £ «. d. 
— 186 run 9" x 3" framed tiebeams (long lengths) . . @ /6J 5 0 9 
— 258 ,, 9" x 3'' framed principal rafters and king 
posts /5 5 7 6 
— 84 „ 3^" x2i" framed struts , /2 0 14 0 
— 376 „ 7'"' x 2 V purlins /3£ 5 9 8 
— 141 „ 9" x 2|" pole plates „ /4 2 7 0 
— — No. 34* squares, 2^" x 2\" common rafters, at 16" 
"centres " „ 9/ 15 10 6 
— 47 run 5" x 1\" ridge /2 0 7 10 
— 184 „ 3" x 1" tilting fillet „ /l 0 15 4 
— — No. 6 wrought-iron f" bolts . . . . „ 1/6 0 9 0 
— — ,, 3 cast-iron pillars and fixing . , . . „ 30/ 4 10 0 
17 — run cast-iron mid-gutter . . . . . „ 2/6 2 2 6 
31 — „ 5" half-round cast-iron eaves spouting and 
holdfasts 1/6 2 6 6 
1 4 — „ 3" circular cast-iron down piping . . . „ 1/3 0 17 6 
— 40 sup. rough plate glass and fixing , 1/ 2 0 0 
383 — „ slating with seconds "Welsh grey slates, 
14" x 8", a space of 2\" being left between 
each slate 1/8 31 18 4 
31 — run blue Staffordshire ridge „ 1/3 1 18 9 
£81 15 2 
The cost of covering the yard by this mode is 81/. 15*. 2c/., 
being at the rate of 5s. h\d. per yard roofed over. 
Board Itoof. 
Fig. 4 illustrates a form of roof that has obtained consider- 
able notoriety within the last few years. It consists of a covering 
of boards from | to 1 inch thick, laid on purlins of 7 inches by 
2^ inches, spaced from 4£ feet to h\ feet apart. These rest on 
principal rafters placed from 14 to 1G feet apart, their scantling 
