On a Dynamical Top, for exhibiting the phenomena of the motion of a system of invariable form about a fixed point, with some suggestions as to the Earth's motion

by James Clerk Maxwell

is a brass screw working in the upper part of the cone

, and capable of being firmly clamped by means of the nut

.

is a cylindrical brass bob, which may be screwed up or down the axis, and fixed in its place by the nut

.