21,726. Patterson, W., and Oldham, O. Oct. 9. Undercutting &c.-Relates to a number of detail improvements in coal-cutting machines, more particularly those described in Specification No. 20,437, A.D. 1902. A single chain a is now used for the feed ; it is connected by swivels p to the carriage b and passes over sprocket-wheels e<1>, e<2> in the undercarriage d. The wheel e<1> is driven through worm gearing g, h and the worm is mounted in an eccentric bush which can be turned by a handle l to throw the worm h in or out of gear with the worm-wheel g. A bridge rest m on the carriage limits the tilting of the machine. The air passages q are cored out of the metal of the cylinders, and are covered by a plate r. The air-supply elbow pipe z is mounted so that it can be turned to either side. A two-way plug valve n, Fig. 6, is provided to connect either the oil inlet v or the air-supply pipe z to the cylinders at will. The cylinder ends are held by bolts and nuts without springs. The handles w are adjustably carried by brackets x.