Early in 1832 he discovered the induction of a current on itself, in a long helical wire, giving greatly increased intensity of discharge (Sill.
Hookes wheels with oblique or helical teeth are in fact screws of many threads, and of large diameters as compared with their lengths.
Crystals with a helical twist are not uncommon.
In wheelwork of this kind the contact of each pair of teeth commences at the foremost end of the helical front, and terminates at the aftermost end; and the helix is of such a pitch that the contact of one pair of teeth shall not terminate until that of the next pair has commenced.
Screws.The figure of a screw is that of a convex or concave cylinder, with one or more helical projections, called threads, winding round it.
Stepped and helical teeth have the desired effect of increasing the smoothness of motion, but they require more difficult and expensive workmanship than common teeth; and helical teeth are, besides, open to the objection that they exert a laterally oblique pressure, which tends to increase resistance, and unduly strain the machinery.
The pitch of a screw is the distance, measured parallel to its axis, between two successive turns of the same thread or helical projection.
Stepped and Helical Teeth.R.
To cause a body to move in this manner it is usually made of a helical or screw-like figure, and moves in a guide of a corresponding figure.
The relation between the advance and the rotation, which compose the motion of a screw working in contact with a fixed screw or helical guide, has already been demonstrated in 32; and the same relation exists between the magnitudes of the rotation of a screw about a fixed axis and the advance of a shifting nut in which it rotates.