THE Safety in Mines Research Board has issued papers Nos. 75 and 76, concerning gob fires, written by T. N. Mason and F. V. Tideswell (London: H.M. Stationery Office, 1933. 1s. net and 6d. net). The first of these deals with the possibility of explosions in sealed-off areas in non-gassy seams, and the second with the possibility of the revival of heating by in-leakage of air. The experiments were carried out in a special building arranged for the purpose at the Experimental Station at Buxton. This building consists of a central chamber 30 ft. square and 9 ft. high to simulate a mine goaf, circumscribed by an air-course approximately 6 ft. wide by 7 ft. high. The chamber and air-course are connected by doors 6 ft. square capable of being closed, and in one corner of the air-course there is a centrifugal blowing fan.