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Proceedings of the Royal Society of Edinburgh. [Sess. 
angular aperture cut in the table. The masses M and L are movable, and 
can be clamped in any desired position, so that any required moment of 
inertia may be imparted to the pendulum. By raising L this can be increased, 
and the positions actually occupied were : M close to the lower plate, and L 
at a distance of 3J feet from it. Towards the end of the short steel rod, to 
which the pendulum is fastened by being passed through its middle point 
