Calculating the dimensions of worm gearing, by R. E. Flanders.--Hobs for worm-gears, by J. Edgar.--Suggested refinement in the hobbing of worm-wheels, by R. E. Flanders.--The location of the pitch circle in worm gearing, by O. E. Perrigo, J. Edgar and R. E. Flanders.--The design of self-locking worm-gears, by C. F. Blake.