The German pointer hunts very
slowly, but surely. It is not difficult to train this dog, but he
cannot be trained until he has reached a certain age.
* * * * *
LUNAR HEAT.
By Professor C.A. YOUNG.
One of the most interesting inquiries relating to the moon is that
which deals with the heat she sends us, and the probable temperature
of her surface. The problem seems to have been first attacked by
Tschirnhausen and La Hire, about 1700; and they both found, that even
when the moon's rays were concentrated by the most powerful
burning-lenses and mirrors they could obtain, its heat was too small
to produce the slightest perceptible effect on the most delicate
thermometers then known. For more than a hundred years, this was all
that could be made out, though the experiment was often repeated.
It was not until 1831 that Melloni, with his newly-invented
"thermopile," [1] succeeded in making the lunar heat sensible; and in
1835, taking his apparatus to the top of Vesuvius, he obtained not
only perceptible, but measurable, results, getting a deviation of four
or five divisions of his galvanometer.
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