According to the measurements of Maclear, Bessel, and
Struve, of the parallaxes and distances of three fixed stars of very unequal
magnitudes ('a' Centauri, 16 Cygni, and 'a' Lyrae), a ray of light requires
respectively 3, 9 1/4, and 12 years to reach us from these three bodies. In
the short but memorable period between 1572 and 1604, from the time of
Cornelius Gemma and Tycho Brahe to that of Kepler, three new stars suddenly
appeared in Cassiopeia and Cygnus, and in the foot of Serpentarius. A
similar phenomenon exhibited itself at intervals in 1670, in the
constellation Vulpis. In recent times, even since 1837, Sir John Herschel
has observed, at the Cape of Good Hope, the brilliant star [Greek symbol] in
Argo increase in splendor from the second to the first magnitude.*
[footnote] *In December, 1837, Sir John Herschel saw the star [Greek
symbol] Argo, which till that time appeared as of the second magnitude, and
liable to no change, rapidly increase till it became of the first magnitude.
In January, 1838, the intensity of its light was equal to that of 'a'
Centauri. According to our latest information, Maclear in March, 1843,
found it as bright as Canopus; and even 'a' Crucis looked faint by [Greek
symbol] Argo.
These events in the universe belong, however, with reference to their
historical reality, to other periods of time than those in which the
phenomena of light are first revealed to the inhabitants of the Earth: they
reach us like the voices of the past.
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