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IV. Corrections applied to the Great Meridional Arc , extending 
from latitude 8 ° 9 ' 38 ", 39 , to latitude 18 0 3 ' 23", 64, to reduce 
it to the Parliamentary Standard. By Lieutenant Colonel W. 
Lambton, F. R. S. and Corresponding Member of the Royal 
Academy of Sciences at Paris. 
Read January 9 , 1823. 
I have recently received from Captain Kater a printed 
paper from the Philosophical Transactions for 1821, giving 
an account of his experiments in examining and comparing 
the different standard scales. I have read with great atten- 
tion and satisfaction the whole of his results, and am glad to 
find that the Commissioners for considering the subject of 
weights and measures, have adopted Mr. Bird's scale of 
1 760, as by that means there is now a universal standard of 
comparison, which applies to the French metre, and to all 
the measures used on the Continent. 
From Captain Kater’s results it appears, that my standard 
scale requires a multiplier of — ,000018 to make it agree 
with the above scale of Mr. Bird ; and that Ramsden's bar, 
used in the Trigonometrical Survey of Great Britain, re- 
quires the multiplier -j- ,00007. That is to say, with respect 
to a measurement on the meridian, the degree depending on 
my brass scale must be multiplied by, 000018 and the pro- 
duct subtracted from the measure given by the scale, to re- 
duce it to what it would have been, had it been measured by 
