704 Mr. button’s Calculations to ascertain 
Now 74A is = 1487*73892 
73B is =1468*04825 
The odd parts 55*773 
Sum 3011*56017 = the bafe unreduced. 
But a reduction of this mult be here made according 
to the ftate of the thermometer, and for the wearing of 
the brafs 5 feet ftandard (fee Phil. Tranf. vol. LVIII. for 
the year 1768, p. 313, See.). Now the difference 
between 62° and 62| being therefore 30x1*56 
x JSSSsfe x 1 = 301 I’S6 X 17^000 X | = 0*024 feet > is 
the fmall correction on account of the thermometer, 
and which being added makes the number become 
30.1 1*584 for the length of the bafe as reduced to the 
ftate of 62° of Fahrenheit’s thermometer. But the 
brafs rod had been x^th of an inch Shortened by wear- 
ing, and it was originally y^th of an inch fhorter than 
the Royal Society’s brafs ftandard yard, fo that it is now 
~dth inch fhorter than that ftandard in the length of 
3 feet, or y^l^th part of the whole ; therefore fubtraCt- 
ing the y^-i^th part, or *167 from the above quantity, 
there remains 3011*417 feet for the corrected meafure 
of this bafe, or the true length of the line rb". 
The above meafures, as far as to that marked * in- 
clufively, together with 10 feet 10) inches more, reach 
4 to 
