The subject for consideration in this section is the covering of buildings for the purpose of protecting them from the weather. The wooden framework for supporting the covering material has been already described under Carpentry (pp. 340-6); there remain for discussion here the various kinds of material used for covering, and the methods of securing them in place. The first detail to be decided on is the "pitch" or slope to be given to the roof, and this will depend both on the nature of the covering material and the character of the climate. In the tropics, where rain falls in torrents, a flat pitch helps to counteract the rush of water; in colder regions the pitch must be such as to readily admit of snow sliding off as it accumulates, to prevent injury to the framework by the increased weight. The pitches ordinarily observed, stated in " height of roof in parts of the span," are as follows : - Lead, 1/40; galvanized iron or zinc, 1/5; elates, 1/4; stone, slate, and plain tiles, 2/7; pantiles, 2/9; thatch, felt, and wooden shingles, 1/3 to 1/2 The various methods of roofing will be discussed in order.