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VII. An account of the comparison of various British Standards 
of linear measure. By Capt. Henry Kater, F. R. S. &c. 
Read January 18th, 1821. 
The Commissioners appointed to consider the subject of 
Weights and Measures, recommended in their First Report 
“ for the legal determination of the standard yard, that 
“ which was employed by General Roy in the measurement 
“ of a Base on Hounslow Heath, as a foundation for the Tri- 
“ gonometrical operations that have been carried on by the 
“ Ordnance throughout the country/' In consequence of this 
determination, it became necessary to examine the standard to 
which the Report alludes, with the intention of subsequently 
deriving from it a scale of feet and inches. 
On referring to the Philosophical Transactions for 1785, it 
may be seen in “ an Account of the Measurement of a Base 
“ on Hounslow Heath," that a brass scale, the property of 
General Roy ( and now in the possession of Henry Browne, 
Esq. F. R.S.), was taken to the apartments of the Royal Soci- 
ety, and being there, with the assistance of Mr. Ramsden, 
compared with their standard ( both having remained together 
two days previous to the comparison), the extent of 3 feet 
taken from the Society's standard, and applied to General 
Roy’s scale, was found to reach exactly to 36 inches, at the 
temperature of 65°. 
It afterwards appears that points, at the distance of 40 
