ather than absolute temperatures, it is
unnecessary, except in an approximate way, to standardize the
thermometers on the basis of absolute temperature. For calibrating the
thermometers, an ordinary wooden water-pail is provided with several
holes in the side near the bottom. One-hole rubber stoppers are inserted
in these holes and through these are placed the bulbs and stems of the
different thermometers which are to be calibrated. The upright portion
of the stem is held in a vertical position by a clamp. The pail is
filled with water, thereby insuring a large mass of water and slow
temperature fluctuations, and the water is stirred by means of an
electrically driven turbine stirrer.

The Beckmann thermometers, of which two are used, are so adjusted that
they overlap each other and thus allow a range of 8 deg. to 14 deg. C.
without resetting. For all temperatures above 14 deg. C., the standard
Richter thermometer can be used directly. For temperatures at 8 deg. C.
or below, a large funnel filled with cracked ice is placed with the stem
dipping into the water. As the ice melts, the cooling effect on the large
mass of water is sufficient to maintain the temperature constant and
compensate the heating effect of the surrounding room-air. The
thermometers are tapped and read as nearly simultaneously as possible. A
number of readings are taken at each point and the average readings used
in the calculations. Making due allowance for the corrections on the
Beckmann thermometers, the temperature differences can be determined to
less than 0.01 deg. C. The data obtained from the calibrations are
therefore used for comparison and a table of corrections is prepared for
each set of thermometers used. It is especially important that these
thermometers be compared among themselves with great accuracy, since as
used in the calorimeter the temperature of the ingoing water is measured
on one thermometer and the temperature of the outgoing water on another.

Thermometers of this type are extremely fragile. The long angle with an
arm some 35 centimeters in length makes it difficult to handle them
without breakage, but they are extremely sensitive and accurate and have
given great satisfaction. The construction of the bulb is such, however,
that the slightest pressure on it raises the column of mercury very
perceptibly, and hence it is important in practical use to note the
influence of the pressure of the water upon the bulbs and make
cor