[ l6 4 ] 
=Iog. B -log. F— 32— -yj .6,75 
= log. B — log. b X 1 + ^ - 8 ~ 8 37 ’ 27 = 
f — 69.27 
478,38 
Where the 
~ Jog. B — log. b X 1 -f- 
anfwer will dill come out in French toifes, though 
adapted to Fahrenheit’s thermometer. To bring it 
out in Englifh fathom (or meafure of 6 feet) multi- 
ply the above expreffion by 1,06575, an d we dial! 
have iogTB — log. b X i + 1 x ’> o 6 S 7 S 
= log. B — log. b x 409,11 + F x =s 
= log. B — log. b x or in round numbers 
448,87 
= log. B — log. b X 
409 ■+- F 
449 
___ ___ __ _p A Q 
— log. B — log. b x 1 4 - — j which will 
449 
exprefs the height between the two dations in 
Englifh fathom. 
In the foregoing expredions, B and b, as has 
been mentioned before, fignify heights of the ba- 
rometer, at the lower and higher ftations, both 
corrected according to Mr. de luc’s directions,, 
for the difference of heat between a fixed tempera- 
ture, (namely -i.th of the interval between freezing 
and boiling water), and the prefent heat, indicated 
by the thermometer attached to the barometer at 
each ftation ; but it is not neceflary, to correct 
both barometers for the effeCt of heat, but only one 
for the difference of heat of the twoj which will 
be more convenient alfo on another account, be- 
cause the difference of heat, at the two ffations* 
will 
