which modern discovery must progress.

Roberts, in South Africa, has done splendid work on the periods of
variables of the Algol type.

_New Stars_.--Extreme instances of variable stars are the new stars
such as those detected by Hipparchus, Tycho Brahe, and Kepler, of
which many have been found in the last half-century. One of the latest
great "Novae" was discovered in Auriga by a Scotsman, Dr. Anderson, on
February 1st, 1892, and, with the modesty of his race, he communicated
the fact to His Majesty's Astronomer for Scotland on an unsigned
post-card.[18] Its spectrum was observed and photographed by Huggins
and many others. It was full of bright lines of hydrogen, calcium,
helium, and others not identified. The astounding fact was that lines
were shown in pairs, bright and dark, on a faint continuous spectrum,
indicating apparently that a dark body approaching us at the rate of
550 miles a second[19] was traversing a cold nebulous atmosphere, and
was heated to incandescence by friction, like a meteor in our
atmosphere, leaving a luminous train behind it. It almost disappeared,
and on April 26th it was of the sixteenth magnitude; but on August
17th it brightened to the tenth, showing the principal nebular band in
its spectrum, and no sign of approach or recession. It was as if it
emerged from one part of the nebula, cooled down, and rushed through
another part of the nebula, rendering the nebular gas more luminous
than itself.[20]

Since 1892 one Nova after another has shown a spectrum as described
above, like a meteor rushing towards us and leaving a train behind,
for this seems to be the obvious meaning of the spectra.