For a roof, thick thatch affords a maximum of protection from both heat and cold; but it is inflammable; needs frequent repairs; and invites the visits of countless birds and rats. I prefer thick flat roofing tiles, especially those which contain a large proportion of iron, to either slates or pantiles; for they give better protection against the weather, and are more durable. Excellent tiles, which are marked "iron," are made at Broseley and Ruabon. A serviceable arrangement is to board the roof with I in. or 3/4 in. boards, which are then covered with roofing-felt securely nailed down, and finally corrugated iron is put over the felt. This, of course, does not look as well as a tiled or slated roof; but it is cheaper; is durable; and gives good protection against wet, cold, and heat. A simple corrugated iron roof will help to preserve a thatched roof over which it is placed; but by itself it affords very little protection against changes of atmospheric temperature. Great additional protection from outside changes of temperature, especially when the roof is directly over the horses, may be gained by constructing an inner roof of, say, 2 in. boards, at about 12 in. from the outer roof, so as to leave between the two a layer of air that will effectively help to prevent outside alterations of temperature from being too rapidly felt by the occupants of the building. The best theoretical arrangement for the roof of a stable is one by which the roof directly covers the horses without any interposing ceiling, against the presence of which there can, however, be no practical objection if the ceiling is not less than about 10 ft. (or 12 ft, if there are several horses) high, and if the stalls and boxes are provided with efficient ventilating shafts, besides good ventilation of the ordinary kind. When a ceiling is present, it is evident that the fact of the roof being made of a material which, like corrugated iron, is a good conductor of heat, is a matter of no consequence as far as the temperature of the stable is concerned;. for the overhead floor and the air contained in the room or rooms of the upper storey will give all the protection that is required in this respect.