T. Russell— Calibration of Thermometers. 377 
final values of 0, the calibration corrections 4, given below 
are obtained by the formula 4,,,=4,+0, 
Correction, 
Ai 
32. 0:00 
42 = —0°01 
52 = +0°07 
62 = +004 
72 — +0°04 
82 = +0°02 
92 = +0°02 
102 = +0:04 
1i2°= 0°60 
122 =.+0°03 
_To get some idea of the accuracy of the determination, the 
differences of observed an omputed values of 0;—d, are 
putation then becomes more tedious. In calibrating, every 
series of measurements with a column ought to be repeated in 
‘ bration correction will not exceed +0°:01. 
The calibration of a thermometer by this method where 
any of the observations with a particular column are lacking 
: offers no special difficulty... When the observations are far 
from being as nearly complete as the example just pre 
sented, good results can nevertheless be obtained, but the com 
Measurements will be free of errors arising from change of 
temperature of the column, provided its temperature is rising 
1 
‘nvert the thermometer quickly and the connection between 
the mercury in the bulb and that above will be broken. In 
case the portion detached is not the length of a column re- 
quired move the mercury until it partially occupies the reser- 
Am. Jour. peau bess * eewes Vou. XXI, No, 125.—May, 1881. 
