For this purpose the water which has passed the
thermometer is made to fall into a funnel hung on the longer arm of a
balanced lever. With an ordinary flow the water stands at a certain height
in the funnel, and, while this is so, the lever remains balanced; but if
from any accident the flow is diminished, the level of the water in the
funnel descends, the other arm of the lever falls, and in doing so
releases two springs, one of which in flying up rings a bell, and the
other by detaching a counterweight closes a cock and stops the supply of
water altogether.
It will be seen that these instruments are not adapted for shifting about
from place to place in order to observe different temperatures, but rather
for following the variations of temperature at one and the same place. For
many purposes this is of great importance. They have been used with great
success in porcelain furnaces, both at the famous manufactories at Sevres
and at another porcelain works in Limoges. From both these establishments
very favorable reports as to their working have been received.--_W.R.
Browne, in Nature_.
* * * * *
[NATURE.]
THE TEMPERATURE OF THE SOLAR SURFACE.
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