G.H. ROSENFELD.
INVENTION AND DISCOVERY.
RECORDING THERMOMETER.--This is a very interesting little machine,
especially so at this time of year when the temperature is a constant
subject for thought.
[Illustration: Thermometer]
It is a recording thermometer, and consists of a thermometer and a
recording disk. By means of cleverly arranged mechanism the rise and
fall of the mercury is used as the motor power, and registers the
changes in temperature on an indicator card. Other simple mechanism
works a rotary drum by which this indicator card is carried.
[Illustration: Pencil Sharpener]
PENCIL SHARPENER.--This is another helpful little contrivance, a pencil
sharpener. There are already numberless things of the kind, some of
which answer for a time, some not at all, and all being made for the
purpose of sharpening the pencil to a kind of regulation point. For my
own part I have always preferred a good sharp knife, or the simple
reason that I could then make exactly the kind of point suited to the
work to be done.
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