and his words have been echoed by others not
less able than himself. "Abolish the observer, and substitute the
sensitive plate," is a sensational form of expressing the revolution in
observational astronomy that is taking place under our eyes; but, although
it suggests a vast amount of truth, it might leave upon the mind an
exaggerated impression inimical to the best interests of science.

The award of the highest distinction in astronomy, the gold medal of the
Royal Astronomical Society, two years in succession, to those who have
been most successful in celestial photography is no doubtful sign of the
great value attached to such work. Last year it was Mr. Common who
received the highest testimony of the merit due to his splendid
photographs of the nebula of Orion; and this year Dr. Huggins, who has
drawn much attention to celestial photography, by his successful attempts
to picture the solar corona in full daylight, has received a similar
acknowledgment of his labors in photographing the spectra of stars and
comets and nebulae.

An adequate idea of the progress astronomy is now making by aid of
photography can only be formed by a comprehensive view of all that is
being at present attempted; but a rapid glance at some of the work may
prepare the way for a more thorough investigation. A few years since, the
astronomers who had advanced their science by aid of photography were few
in number, and their results are soon enumerated. Some good pictures of
the solar corona taken during solar eclipses, a series or two of sun-spot
photographs, and a very limited number of successful attempts made upon
the moon, and planets, and star clusters, were all the fruits of their
labors. But now each month we learn of some new and efficient laborer in
this field, which gives promise of so rich a harvest.

Each day the sun is photographed at Greenwich, at South Kensington, in
India, and at the Physical Observatory of Potsdam, and thus a sure record
is obtained of all the spots upon its surface, which may serve for the
study of the periodicity of its changes, and for their probable connection
with the important phenomena of terrestrial magnetism and meteorology. In
France the splendid sun-pictures obtained by Dr. Janssen at the Physical
Observatory of Meudon have thrown into the shade all other attempts at a
photographic study of the most delicate features of the solar surface.

Dr. Huggins has shown that it is possible to obtain a dail