376' Dr. Ure’s new experimental researches 
Let us take a thermometer, the calibre of whose stem is 
perfectly uniform, and whose scale is exactly divided. Let 
it have a range from zero to the 656th degree, at which 
mercury boils, by the accurate experiments of Creighton. At 
32 0 , let the mercury stand at the bottom of the ivory scale, 
where of course the graduations commence. The bare part 
of the instrument is consequently the plunging limit, in most 
chemical researches on the temperature of liquids. Immerse 
the bulb in common oil, or oil of vitriol heated to 212 0 ; * 
part of the whole included mercury, will now ascend above 
that part of the stem plunged in the liquid. The part actually 
exposed to the heat, and by whose expansion the column on 
the scale is supported, is only of the initial mass. Augment 
the heat of the oil till the instrument indicate 392 0 ; we know 
that there remains now, under the immediate influence of the 
heat, f §■ nearly of the original weight of mercury ; and finally, 
at 572 0 , only about rest in the immersed part of the stem 
and bulb. 
■£2 or jV parts may be considered as no longer subjected 
to the power of caloric. If the thermometer stem were 
recurved near the bulb, the mercury in the stem placed hori- 
zontally would be cold ; and this proposition would be almost 
exactly true. 
Now, since the calibre and divisions are uniform, the 
capacity of the tube from the point marked 212 0 , to that 
marked 3 92 0 ; and again from this, to that opposite to 572°, 
is in each equal to its capacity from 32 0 to 21 2 0 . Hence 
these three equal capacities are tilled by the expansions of 
the three unequal quantities of mercury 62, 61 , 60. At the 
# A minute fraction less ; but we need not complicate the statement with it. 
