474 
Covered Cattle Yards. 
my experience as to this is not singular, but could be confirmed 
by that of many others. 
On numerous large estates in different parts of the country 
Covered Yards are accomplished facts, and on many others the 
improvement is being gradually carried out, so that no special 
pleading is required to further the adoption of the system. 
Their increase now chiefly depends on the power of the laud- 
owner to supply them, and, given this power, the choice of 
covering material, suitable design, and efficient construction at 
an economical rate, is a problem ever-recurring for solution. I do 
not pretend to have discovered a key to this problem, but, by illus- 
trating the various modes of roofing now existent, detailing 
cost, principles of construction, and the merits of each, I hope to 
be able to place such data before those interested as will enable 
them to compare, and so to solve it for themselves. 
In the construction of Covered Yards the first essential to 
be kept in view is to secure 
Efficient Ventilation. 
When this is wanting, cattle kept in them cannot thrive 
well, and one of the chief advantages derivable from their use 
is marred. The object of cover is to shelter, but not to tender, 
and, in order to this, plenty of air must be forthcoming, but so 
admitted as not to impinge on the cattle, or create draughts — 
both being prejudicial to their health. Experience has proved 
that this can be best attained by openings at eaves height of the 
building to let the air in, while a break high up in the roof 
induces a through current and draws off the heated foul air from 
below. 
This is known as " roof ventilation" (in contradistinction 
to " wall ventilation," which allows a free current of air to enter 
the yard over low end or side walls at a height little above that 
of the animals kept in it), and was an invention of the late Sir 
Harry Meysey Thompson, and fully described by me in the 
paper referred to. 1 It would be needless repetition to detail it 
again, but, the principle being a correct one, it will be briefly 
described, and a design of roof on that system given, as suitable 
to carry a covering of slates or tiles. 
Covering Materials. 
The materials used for roof-cover of Cattle Yards in 1 865 
were chiefly slates and pantiles. The latter have been very exten- 
1 Vol. I. Part I. 2nd Scries, p. 88. 
