The spectrum of Coggia's Comet was examined
at every available opportunity last July, and compared directly with
that of carbon dioxide, the bands of the two spectra being sensibly
coincident. Fifty-four measures of the displacement of lines in the
spectra of 10 stars, as compared with the corresponding lines in the
spectra of terrestrial elements (chiefly hydrogen), have been made,
but some of these appear to be affected by a constant error depending
on faulty adjustment of the Spectroscope.--Photographs of the Sun have
been taken with the Kew Photoheliograph on 186 days; and of these 377
have been selected for preservation. The Moon, Jupiter, Saturn, and
several stars (including the Pleiades and some double stars) have been
photographed with the Great Equatoreal, with fairly satisfactory
results, though further practice is required in this class of work.--I
would mention a supplemental mechanism which I have myself introduced
into some chronometers. I have long remarked that, in ordinary good
chronometers, the freedom from irregularities depending on mechanical
causes is most remarkable; but that, after all the efforts of the most
judicious makers, there is in nearly every case a perceptible defect
of thermal compensation.
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