300
plat incur wire is drawn through, it. This sv ter. is immersed in .. ;J or
and the variations in the electrical resistances measured.
figure are shown, also, the mercury switches imbedded, in paraffin or
making connections and the telescope and millimeter scale. I" . -
ratus for temperature measurements is extremely complex, the ' ' :-
fit consisting of the following pieces of apparatus:—
Telescope and scale;
galvanometer with special suspension,
Three resistances running from
0.1 to 50 ohms
0.1 to 5000 ohms
0.1 to 10,000 ohms
A normal resistance of 10 ohms;
A complicated compensation apparatus;
A platinum thermometer.
Conferring with the officials of the Physikalisch**-Tech ;/.e
Eeichsanstalt, Prof. Fischer has succeeded in assembling this app ran;;.,
for the electrical measurement of temperature, which gives most
fully satisfactory results. The rise it - .ith a acc :
l/sooo of a degree Centigrade. Consequently, the whole system is
adjusted as to give a rise of only one degree, thus eliminating i a
marked manner any tendency for a cooling correction.
The general appearance of the bomb calorimeter room is snewr. m
Fig. 96. In the further corner, surrounded by a cardboard or asbe;■’■a
box, is the galvanoineter. One side of the protecting sue air has a ‘
through for the beam of light to pass in and out. On the "loor a
calorimeter vessel with a pulley system on a standard above, V e ystem
being actuated by an electric motor near the window. When i t opera* ! p
the central part of the calorimeter chamber is closed. The water mantle
is constructed of copper. On the table at the left are the three re¬
sistances and the compensation apparatus. This is covered and not
shown in the photograph. The apparatus on the two tables at the right
is used for another research and is of interest only in tha+ the telesc ge