C 68. ] 
XXXII. Comparifon between Sir George Shuckburgh and 
Colonel Roy’s Rules for the Meafurement of Heights with 
the Barometer ; in a Letter to Col. Roy, F. R. S. from 
Sir George Shuckburgh, Bart. F. R. S. 
Read ] INCE the printing of your ingenious 
heights with the barometer, I have been naturally led to 
a comparifon of your rules and obfervations with my 
own w ; and herein am not more pleafed than furprized at 
the general correfpondency of our refults, which carries 
with it the appearance of one and the fame feries of ex- 
periments, rather than of diftindt obfervations made with 
different inftruments, in different countries, and by dif- 
ferent perfons. That the ftandard temperature or zero 
on the fcale of the thermometer fhould be found by each 
of us to fall in the fame point to within one-third of a 
degree is, I think, truly furprizing; and I doubt not will 
evjnce to Mr. de luc the ftrong probability there is of 
(a) Vide Phil. Tranf. vol. LXVII. 
TQ COLONEL ROY 
SIR 
Welbeck Street, 
April 1776, 
memoir on the fubjedt of meafuring 
Vol. LXVIII 
4 P 
the 
