[ 297 ] 
TABLE III. 
equation for the temperature of the quicksilver. 
The numbers in the firft column 
are to be underftood to exprefs differ- 
ences of temperature, in the quick- 
filver of the portable Barometers at 
the two ftations, indicated by Ther- 
mometers fixed in the cafes of the 
Barometers, in degrees of Bird’s 
Fahrenheit. The fecond column 
gives the correfponding correftions 
of the difference of the tabular lo- 
garithms of the obferved heights of 
the quickfilver in the barometer, to 
be added or fubtrafted, according as 
the higher barometer hath been the 
warmer or cooler of the two. The 
numbers in the third column are the 
WWth parts of thofe in the fecond. 
The manner of ufing them is ex- 
plained in the general precepts. The 
fourth column gives the reduction of the obferved height of the column 
of quickfilver, in decimal parts of an inch, for the differences of tem- 
perature expeeffed by the numbers of the firft column, when the height 
of the quickfilver is 30 inches ; and the reduftion for any other height 
cf the qnickfilver may be thus found. Suppofe the height of the ba- 
rometer 30 dz a inches, in a certain temperature b, and this is to be 
reduced to the temperature l =h n. From the fourth column coll eft the 
number correfponding to n (by repeated entry, if need be). Call that 
number M. Then M dz — M is the reduftion. 
3 ° 
Degrees 
of Bird’s 
Fahrenh. 
Correction 
of Diff. 
Logarith. 
Fathom 
1 
45 2 
0,442 
0,003 
2 
9°4 
0,904 
0,006 
3 
1355 
J >3 55 
0,009 
4 
1807 
1,807 
0,01 2 
5 
2259 
2,259 
0,016 
6 
271 1 
2,711 
0,019 
7 
3 l6 3 
3> i6 3 
0,022 
8 
3614 
3 , 6 j 4 
0,025 
9 
4066 
4,066 
0,023 
10 
4 5 l8 
4 . 5 i 8 
0,031 
20 
9036 
9,036 
0,062 
30 
J 3554 
' 3.554 
0.094 
40 
18072 
18,072 
0,125 
5 ° 
22490 
22,590 
0,156 
60 
27108 
27,108 
0,188 
70 
31626 
31,626 
0,219 
Vol. LXIV, 
Qq 
TABLE 
