t happen again that an astronomer shall hear for a
half hour, the same hour struck by different clocks, as Delambre told me
he had often experienced. M. Chabrol, the Prefect of the Department of
the Seine, before he would introduce this useful change, required, as a
guaranty for himself, a report from the Board of Longitude: he was
fearful that the change might provoke the working population to
insurrection; that they might refuse to accept a mid-day or noon which,
by a contradiction in terms, would not correspond to the middle of the
day; which would divide in two unequal portions the time comprised
between the rising and the setting of the sun. But this sinister
anticipation was not realized; the operation passed without being
perceived." It is all important, on the railroads, that the clocks at
the different stations should be so regulated. Arago remarks that among
the ancients it would have been dangerous to announce the existence of
more than seven planets, owing to the "mysterious virtues" ascribed to
that number; to complete it the sun was counted among the planets. He
discusses the point--which is the first day of the week, and decides for
Sunday. He devotes a section to the question--"Will the period come when
the days will be equal between themselves, and have the same temperature
throughout the year?" He concludes, of course, in the negative. He
decides, also, that the nineteenth century began only on the 1st of
January, 1801. Particular interest may be attributed to the section on
the long series of ages which the ancients invested with the title "The
Great Year." The high names of Plato, Cicero, Seneca, Plutarch, should
not prevent us from regarding the opinions of antiquity on the relations
of the great year, with the events of every kind observable on the
earth, as among the crudest conceptions that have descended to the
moderns.

At the sitting of the _Academy of Sciences_ on the 24th ult., M.
AUGUSTIN CAUCHY read a memoir on the transversal vibrations of ether,
and of the dispersion of colors. He furnished a simple, and easily
intelligible mathematical theory of the various phenomena of light, and
particularly, the theory of the dispersion of colors. Lord Brougham read
a paper of his _Researches, Experimental and Analytical, on Light_. His
Lordship's ambition is to shine in optics, as in every thing else; but
you will see by a London paragraph that his researches have nearly cost
him his eyesight. Dr. A