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

7IIE EDINBURGH TINE-GUN.

The time-gun at Edinburgh Castle has now continued
for nearly a year regularly to annoufice the precise instant
of one o'cloak Greenwich time, and it LW now be regarded
as a completely successful experiment. A s formerly noticed
in The Sun, the gun is discharged by a frimple piece of
mechanism attached to a clock at the battery. This clock is
regulated and controlled by the clock of the licrs'al Obser-
vatory on the Calton-hill, which is carefully adjusted to
Greenwich time by astronomical observations mode from
hour to hour. The two clocks are kept en rapport, so to
speak, by means of an electric wire suspended in one &train.
over the valley between the Old and New Town, the dis-
tance from the Castle to the Calton-hill being about threct.
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 dilstance
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 beeii
propose 1 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, rife.
shire, the report is distinctly heard along the opposAo
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 tho
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 suggestions have also been made for the
improvement or mr 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 ia
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
defective fuze, but this is of very rare occurrence. The gull
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, ail
conversation is stopped for the moment till every one ascer-
tains that his watch is keeping time.

COUNTRY MABEL 2 AS'.

.),,

COLCHESTER—MAY 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
red 56s
Barley
Oats

62s Beans, Mazagan 3ss 368
60s middle & small 37s 408
42s Peas, white 38s 42s
—s gray 38s 42e

CIIELMSFO
A good supply of wheat to
trade, and may be quoted full
All Spring corn firm.
Wheat, old white...24s 57s
new ..43s 6461

old red.... 23s 49s

new 48 608
Barley 30s 39s
Chevalier ..... 3Us 420

Grinding 24s 32s
Malt.... 61s 67s
Chevalier 64s 69s
Oats 23s 30s