he
clock-times were carried on entirely by the preceding rate of the
clock. The accumulated error at the end of this time did not exceed
0s'3.--Some difficulty was at first experienced with the Thomson
Electrometer, which was traced to want of insulation. This has been
mastered by the use of glass supporters, which carry some sulphuric
acid. The instrument is now in excellent order, and the photographic
registers have been perfectly satisfactory since 1879, February, when
the new insulators were applied.--From the annual curves of diurnal
inequality, deduced from the Magnetic Reductions, most important
inferences may be drawn, as to the connection between magnetic
phenomena and sun-spots. These annual curves shew a well-marked
change in close correspondence with the number of sun-spots. About the
epoch of maximum of sun-spots they are large and nearly circular,
having the same character as the curves for the summer months; whilst
about the time of sun-spot minimum they are small and
lemniscate-shaped, with a striking resemblance to the curves for the
winter months. The connection between changes of terrestrial magnetism
and sun-spots is shewn in a still more striking manner by a comparison
which Mr Ellis has made between the monthly means of the diurnal range
of declination and horizontal force, and Dr R. Wolf's 'relative
numbers' for frequency of sun-spots.--The records of sunshine with
Campbell's Registering Sun-dial are preserved in a form easily
accessible for reference, and the results are communicated weekly to
the Agricultural Gazette.--Prof. Oppolzer's results for the
determination of the longitudes of Vienna and Berlin, made in 1877,
have now been made public. They shew a remarkable agreement of the
Chronometric determination formerly made with the Telegraphic. It may
be of interest to recall the fact that a similar agreement was found
between the Chronometric and Telegraphic determinations of the
longitude of Valentia.--For observing the Transit of Venus of 1882,
the general impression appears to be that it will be best to confine
our observations to simple telescopic observations or micrometer
observations at Ingress and Egress, if possible at places whose
longitudes are known. For the first phenomenon (accelerated ingress)
the choice of stations is not good; but for the other phenomena
(retarded ingress, accelerated egress, retarded egress) there appears
to be no difficulty.--With regard to the Numerical Lun