Light Science for Leisure Hours: A series of familiar essays on scientific subjects, natural phenomena, &c.Proctor, Richard A. (Richard Anthony)
Science
Light Science for Leisure Hours: A series of familiar essays on scientific subjects, natural phenomena, &c.
Proctor, Richard A. (Richard Anthony)
Science
It was supposed after the total solar eclipse of 1869 that the spectrum
of the sun’s corona exhibited the same bright lines as the aurora. But
recent observations show that the coincidence is not so close as had
been supposed, and, in fact, there is no evidence to show that the
lines are the same.
(From _Fraser’s Magazine_, February 1870.)
_THE EARTH A MAGNET._
There is a very prevalent but erroneous opinion that the magnetic
needle points to the north. I remember well how I discovered in
my boyhood that the needle does _not_ point to the north, for the
discovery was impressed upon me in a very unpleasant manner. I
had purchased a pocket-compass, and was very anxious—not, indeed,
to test the instrument, since I placed implicit reliance upon its
indications—but to make use of it as a guide across unknown regions.
Not many miles from where I lived lay Cobham Wood, no very extensive
forest certainly, but large enough to lose oneself in. Thither,
accordingly, I proceeded with three schoolfellows. When we had lost
ourselves, we gleefully called the compass into action, and made
from the wood in a direction which we supposed would lead us home.
We travelled on with full confidence in our pocket guide; at each
turning we consulted it in an artistic manner, carefully poising it and
waiting till its vibrations ceased. But when we had travelled some two
or three miles without seeing any house or road that we recognised,
matters assumed a less cheerful aspect. We were unwilling to compromise
our dignity as ‘explorers’ by asking the way—a proceeding which no
precedent in the history of our favourite travellers allowed us to
think of. But evening came on, and with it a summer thunder-storm. We
were getting thoroughly tired out, and the _hæc olim meminisse juvabit_
with which we had been comforting ourselves began to lose its force.
When at length we yielded, we learned that we had gone many miles out
of our road, and we did not reach home till several hours after dark.
Also the offending compass was confiscated by justly indignant parents,
so that for a long while the cause of our troubles was a mystery to us.
In reality, instead of pointing due north, the compass pointed more
than 20° towards the west, or nearly to the quarter called by sailors
north-north-west. No wonder, therefore, that we went astray when we
followed a guide so untrustworthy.
Public-domain text, read in full here on John Shaqi.
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