A wheel and axle may be combined with a screw, as shewn in the contrivance of fig. 61. When the handle is turned, the screw-thread on its axle sends the cog-wheel forward one tooth for every revolutio [...]
A lever and an inclined plane may be combined together into a screw-press, the incluned plane being coiled up into a spiral or screw-thread (fig. 59). For every complete revolution of the lever, the [...]
