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VIII. An Account of some Endeavours to ascertain a Standard of 
Weight and Measure. By Sir George Shuckburgh Evelyn, 
Bart. F. R. S. and A. S. 
Read February 22, 1798. 
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§. 1. 
Having for some years turned my thoughts to the considera- 
tion of an invariable and imperishable standard of weight and 
measure, as being a thing, in a philosophical view, highly de- 
sirable, and likely to become extremely beneficial to the public, 
I had, so early as the year 1780, taken up the idea of an uni- 
versal measure, from whence all the rest might be derived, by 
means of a pendulum with a moveable centre of suspension, 
capable of such adjustments, as to be made to vibrate any num- 
ber of times in a given interval; and, by comparison of the 
difference of the vibrations with the difference of the lengths of 
the pendulum, (which difference alone might be the standard 
measure,) to determine its positive length, if that should be 
thought preferable, under any given circumstances ; by which 
means, all the difficulties arising in determining the actual 
centre of motion and of oscillation, which have hitherto so 
much embarrassed these experiments, would be gotten over. 
(§.2.) I made several computations of the probable accuracy 
that might be expected from such an experiment, and was sa- 
tisfied with their result. But, not seeing clearly how such a 
pendulum could be connected to a piece of mechanism, to 
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