Modern instruments and methods of calculation : a handbook of the Napier Tercentenary Exhibition (1914)
Horsburg, E. M. (Ellice Martin), Napier Tercentenary Exhibition (1914 : Edinburgh, Scotalnd) · London : G. Bell · leaf 250
to its plane and passing through itscentre. The cylinder, which is not in contact with the disc, can rotate aboutits axis, which is parallel to the plane of the disc. The sphere is always incontact with the disc and the cylinder, and can roll along, keeping in contactwith both and not making either… … Fig. i. As a planimeter, the instrument evaluates an integral of the form f(6)d0, but Lord Kelvin 3 pointed out that it can be utilised to evaluate an integral of the form \J{Q)<p{Q)d9 in the following manner:—Suppose a point in the circumference of the disc whose radius is R receives an…
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer02inte-159-67.webp)
