The Sun.
London, England, 1862-05-13 00:00:00

111 E EDINBURGH 2LIIE-GUIV.

The time-gun at Edinburgh Castle has now continued
for nearly a year regularly to announce the precise instant
of one o'clock Greenwich time, and it may now be regarded
as a completely successful experiment. As formerly noticed
in The Sun, the gun is discharged by a simple piece of
mechanism attached to a clock at the battery. This clock is
regulated and controlled by the clock of the Royal Obser-
vatory on the Calton-hill, which is carefully adjusted to
Greenwich time by astronomical observations made from
hour to hour. The two clocks are kept en rapport, so to
speak, by means of an electric wire suspended in one strain
over the valley between the Old and New Town, the dis-
tance from the Castle to the Calton-hill being about three-
quarters of a mile. Simultaneously with the audible signal,
a large time-ball on the summit of Nelson's Monument
drops. The flash of the gun and the fall of the time-ball of
course communicate the exact second, at whatever distance
the state of the atmosphere may render them visible, but
allowance has to be made according to distance for report
of the time-gun. Thus, on the top of Arthur Seat seven
seconds elapse before it is heard, and at the shipping ports
of Leith and Granton 11 or 12. On the Edinburgh and
Leith Directory map circles are traced showing the dis-
tances reached by the report at each successive second up
to 13 ; but as, notwithstanding the small charge of powder
employed (only 41b., not to render the effect too startling to
inhabitants residing near the Castle), the gun is audible at
even above 20 miles' distance in quiet weather, it has been
propose] to issue certain sheets of the Ordnance Survey
maps with five. second circles marked. According to a
paper lately read before the Royal Scottish Society of Arts
by Mr. Daniel Campbell, forester at Wemyss Castle, Fife,
shire, the report is distinctly heard along the opposite
shores of the Firth of Forth ; it penetrates to the centre of
the Fife peninsula, the clocks in Markinch, 21 miles dis-
tant, being regulated by the gun. A good deal of corro-
borative testimony has been obtained to the effect that the
report is even heard near Fifeness, and Mr. Hewat, the
originator of the scheme, states that he has heard it at Dun-
bar, on the south shore of the Forth, 28 miles from Edin-
burgh. Mr. Campbell, in his paper, proposed that railway
companies and town-councils should unite to plant time-
guns over the country in prominent situations, at probably
20 miles' distance from each other. This idea is somewhat
too far-sighted, but the success of the Edinburgh gun has
led to numerous proposals to establish audible signals else-
where, and various suggest'ons have also been made for the
improvement or m, dification of the mechanism employed.
The subject has been brought under the notice of the Tyne
Commissioners, and in the Clyde it has been suggested that
a time-gun should be fired from Dumbarton Castle, which
would conveniently give the signal to the Greenock ship-
ping. It may be mentioned that, apart from the abortive
trials of the first two days, the Edinburgh gun has failed in
only one, or probably two instances. The mechanical ar-
rangements have worked remarkably well, and probably the
only risk which cannot he effectually guarded against is a
defective fuze, but this is of very rare occurrence. The gun
is fired daily, excepting Sundays and days set apart for
public worship, such as the sacramental fast days and Good
Friday. By the inhabitants of Edinburgh the time-gun is
regarded as a great benefit ; and as the report is heard on
the streets, in places of business, or in public meetings, all
conversation is stopped for the moment till every one ascer-
tains that his watch is keeping time.

COUN2RI MARKI42IS'.

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COLCHESTER-MAv 10.

A good supply of wheat, but the business done was slow
at is per qr decline. Barley rather cheaper. Beans fully
as dear. No peas.
Wheat, white 58s 62s Beans,Mazagan..3ss 36s
red 56s 6os middle & small.37s 40s
Barley
Oats

IRD-MAY 9.

-day, which met with a slow
ay 2s per qr below late prices.

E'eas, Partridge 378 418
White 398 42s
Bonin ; . 4ls 44s
Dun 36s 40s
Ditto new —B —s
Beans, Tick, old 33s 38s
new 33s 38s
Harrow Ticks 37s 43s
new-35s 408
Mazagan 3ls 41s