COMMUNICATION 1 OF MOTION IN MACHINES. 61 



#, as f 1, f % f 3, &c. will have made two revo- 

 lutions to e 1, e 2, e 3, &c. and if the cones were 

 fluted, or had teeth cut in them, diverging from 

 the centre a to the bases d c, e f (Fig. 7), they 

 would then become bevel-geer. The teeth at the 

 point of the cone being small, and of little use, 

 may be cut off at E and F (Fig. 7« and 8.) where 

 the upright shaft a b, with the bevel-wheel c d, 

 turns the bevel-wheel e f with its shaft b g, and 

 the teeth work freely into each other. The teeth 

 may be made of any dimension, according to the 

 strength required ; and this method will enable 

 them to overcome a much greater resistance, and 

 work smoother than a face-wheel and wallower of 

 the common form can possibly do ; besides, it is of 

 great use to convey a motion in any direction, or 

 to any part of a building, with the least trouble 

 and friction. 



The method of conveying motion in any direc- 

 tion, and proportioning or shaping the wheels 

 thereto, is as follows : Let the line a b fig. 9. re- 

 present a shaft coming from a wheel ; draw the 

 line c d to intersect the line a b in the direction 

 that the motion to be conveyed is intended, which 

 will now represent a shaft to the intended motion. 



Again, suppose the shaft c d is to revolve three 

 times, whilst the shaft a b revolves once; draw 

 the parallel line i i, at any distance not too great 

 (suppose one foot by a scale,) then draw the 

 parallel line k k at three feet distance; after which, 

 draw the dotted line w x through the intersection 

 of the shafts a b and c d, and likewise through the 

 intersection of the parallel lines i i and k k, in the 

 points t r and y, which will be the pitch-line of the 

 two bevel- wheels, or the line where the teeth of 



