Small wheels fixed to heavy household furniture, as tables, sofas, etc. to admit of moving them with facility. The annexed engraving represents an improvement upon the common construction, by the introduction of small antifriction rollers, by which means the strain and pressure upon the central pin is removed, and the small wheel readily assumes the proper direction. It is the invention of Mr. Harcourt, of Birmingham. Fig. 1 is a side view of the castor, the upper or socket part only being in section; a a is a guide plate fixed round the central pin so as to revolve with it: this plate has circular holes made through it, in each of which is a little spherical ball, which rolls as it is carried round with the plate. Fig. 2 gives the plan of the guide plate a, which has three or more apertures for the antifriction rollers, and these rollers may be either spherical or cylindrical; for which reason two of them are shown in this diagram as spherical, and one as cylindrical.