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ARTICLE XXI. 
4 An improved Pedometer defcribed. 
{With a Plate. } 
By Mr. L. TucweE tt, of Beverftone. 
SIR, 
OU will obferve under the article Perambu- 
lator, in the, Cyclopadia of Chambers, that 
its proper application is where for meafuring roads 
and large diltances, great expedition, and not much 
accuracy, is required !—This want of accuracy will 
be obvious enough to every infpector to arife from 
the too fmall dimenfions of its meafuring wheel; 
it too readily thereby, in its application, adapting 
iifelf to the cafual inequalities of the furface; and 
hence the defideratum of fome contrivance for ad- 
mitting a larger wheel for obviating the defect. 
This, fome years fince, was attempted by Mr. Edg- 
worth, whofe machine for the purpofe feems the 
moft fimple that can be conceived ; while, however, 
(fimplicity being in mechanics a criterion of ex- 
cellence, and probably from confidering, in addition 
to the above-mentioned defect in the old one, its 
too great complexity) he feems to have gone into 
the oppofite extreme, and, almoft through the 
whole of his own, to have facrificed utility to an 
unneceflary degree of brevity. 
Mentioning thefe matters to you fome time fince, 
and that I had, from the obvious utility of a perfect 
- machine 
