Iron tower 13

Flat-roofed con­crete building 15

Steel tower

Grey circular gra­nite tower, black lantern 117

A red fixed light on flagstaff at North pier"' head prohibits entry or departure of ves­sels.

Eclipse 2.5 sec; Visible from 179°, through south, to 269°. In line with Castle Cornet breakwater light (No. 460) 220°, leads-through Little Russel.

Flash 1.0 sec; eclipse 1.5 sec; flash 1.0 sec? eclipse 1.5 sec; flash 1.0 sec; eclipse 4.0 sec; Red from 185° to 191° white thence to 011°; red thence to 081°; obscured else­where.

Blast 1.0 sec; silent 2.5 sec; blast 1.0 sec; silent 2.5 sec; blast 1.0 sec; silent 22.0 sec

Also shows a red identification light giving a group of flashes corresponding to the Morse letter G ( ). Both lights nor- mally shown only for a few hours after sunset during the winter months.

Flash 9.0 sec Visible from 294°, through north to 237°. The following signals are made at this light-house to summon as­sistance to any vessel in distress or diffi­culties. By Day or Night:— Two explo­sive rockets fired at short intervals. Reply: By day. — Red flag followed by one or more explosive sound signals. By night.— Rocket throwing white stars on bursting, or one or more explosive sound signals throwing white or green stars on bursting.

One stroke every 15.0 sec; explosive signal one report every 5.0 min.

Flash 2.0 sec. white from 095 thence to 173°; white thence thence to 268°; white thence to scured elsewhere.

to 112°; to 230°; 273°;

60

12

484

Circular concrete tower 9

White octagonal iron tower 30

ALL BEARINGS ARE TRUE, FROM SEAWARD

red red ob-

For hydrographic purposes a light is characterised as flashing or occulting solely according to the relative durations of light and darkness, and without any reference to the apparatus employed. At short distances, and in clear weather, flashing lights may show a faint continuous light.

Period is the interval between successive commencements of the same phase, i. е., in a flashing light the interval between the commencement of one flash and the commencement of the succeed­ing flash, and in occulting, alternating, and group flashing lights, &c, the time occupied by the exhibition of the entire system of changes included in the same phase.

The durations of light and darkness given in the column for remarks are, as a rule, those for which the apparatus was designed. In practice they are subject to some degree of fluctuation, owing to slight variations in the working speed of the apparatus. The duration of a flash may also appear to be less than normal when seen from a great distance, and haze has the same apparent effect.

ELEVATION and HEIGHT.—The elevation given in column 6 is measured between the centre of the lantern and the level of mean high water springs. The height given in Column 9 is that of the structure, measured from top to base, except in the case of lights in French territory, where the heights of structures are given from the focal plane to the ground.

VISIBILITY. —The distances from which the lights are visible in clear weather are calculated in nautical miles as seen from a height of 15 feet above the sea, the elevation of the lights being in all cases taken as above mean high water springs.

Under certain atmospheric conditions and especially with the more powerful lights, the glare of the light is visible considerably beyond the radius given, which is calculated for the focal plane of the light.

THE POWER OF THE LIGHTS, whenever obtainable, is given in units of 1,000 candles. Thus, the. figure 22 means 22,000 can­dles, 2/10* means 200 candles.

CAUTION.—The power of light should always be considered when expecting to make it in thick weather. A weak light is easily obscured by haze, and no dependence can be placed on its being seen.

It should be remembered that lights placed at a great eleva­tion are more frequently obscured by clouds than those near the sea level.

The power of a light whose candle power is not given can be estimated in some cases by noting how much its visibility in clear weather falls short of the range due to the height at which it is placed. Thus a light placed at 200 feet above the sea, and recorded as visible only 10 miles in clear weather, is manifestly of little brilliancy, as its height would permit it to be seen over 20 miles if of sufficient power.

The Bearings are true, and in degrees from 000^Q (North) to 359° measured clockwise, and are given from seaward; the limits of sectors and arcs of visibility are invariably arranged from left to right.