Chapter IV: Front Matter (4)

+--------------------------+-----------------+-----+----------+-----------+----------+-------------+-------+----+--------+--------------------------+----------+--------+---------+-------+---------------------------------------------------+
| | | P | | | | | C | V | C | | | | | | |
| | | e | | | | Ratio of | u | o | a | | | | | | |
| | | r | | Candle- | Focal | Angular | r | l | r | | | |Elevation| Year | |
| Name. | Characteristic. | i | Duration | power | Distance | Breadth of | r | t | b | Electric | Lamps. |Engines.| above | Estab-| Remarks. |
| | | o | of Flash.| (Service | of Lens. | Panel to | e | a | o | Generators. | | | High |lished.| |
| | | d | |Intensity).| |Whole Circle.| n | g | n | | | | Water. | | |
| | | . | | | | | t | e | s | | | | | | |
| | | | | | | | . | . | . | | | | | | |
+--------------------------+-----------------+-----+----------+-----------+----------+-------------+-------+----+--------+--------------------------+----------+--------+---------+-------+---------------------------------------------------+
| | | | | Standard | | | | | | | | | | | |
|UNITED KINGDOM-- | |Secs.| Secs. | Candles. | mm. | | Amps. | | mm. | | | | Feet. | | |
| Souter Point | Single flash | 30 | 5 | | 500 | 1 : 8 | .. | 40 | 17 | Holmes machines, | Serrin | Steam | 150 | 1871 |Fixed light apparatus, with revolving vertical |
| (Durham) | | | |\ C n | | | | | | alternating (400 revs.) | | | | | condensing lenses in eight panels. |
| South Foreland | Single flash | 2.5| .35 || a o d | 700 | 1 : 16 | .. | 40 | 26 | do. | Serrin | Steam | 374 | 1904 |Lens elements only; 97° vertical angle. |
| (Kent) | | | || n t e | | | | | | | | | | | (This apparatus was in use at St Catherine's, |
| | | | || d t | | | | | | | | | | |1888 to 1904, and replaced the two fixed electric |
| | | | || l o e | | | | | | | | | | |lights established in 1872.) |
| Lizard | Single flash | 3 | .13 || e f r | 700 | 1 : 4 |145 for| 40 | 50 and | De Meritens alternators | Modified | Oil | 230 | 1903 | Mercury rotation; vertical angle, 139°. Replaced |
| (Cornwall) | | | | > - f m | | | 50 mm.| | 60 | (600 revs.) | Berjot- | engines| | | the two fixed electric lights erected in |
| | | | || p i i | | |carbons| | fluted | | Serrin | | | | 1878. |
| St Catherine's | Single flash | 5 | .21 || o c n | 700 | 1 : 4 |145 for| 40 | 50 and | do. | do. |2 Steam,| 136 | 1904 |Mercury rotation; vertical angle, 139°. |
| (Isle of Wight) | | | || w i e | | | 50 mm.| | 60 | | | each 50| | | |
| | | | || e a d | | |carbons| | fluted | | | h.p. | | | |
| Isle of May | 4 flash | 30 | .4 || r l . | 700 | 1 : 8 | 220 | 40 | 40 | do. | Berjot- | Steam | 240 | 1886 |Fixed light apparatus, with revolving vertical |
| (Firth of Forth) | | | || l | (Fixed | | | | | | Serrin | | | | condensing lenses. |
| | | | |/ y |apparatus)| | | | | | | | | | |
|FRANCE-- | | | | | | | | | | | | | | | |
| Dunkerque | 2 flash | 10 | .2 to .4 | 3,500,000 | 300 | 1 : 12 | 30 | 45 | 14 and |2 De Meritens alternators,| Improved | 2 Semi-| 193 | 1902 |Twelve panels in groups of two. |
| (Strait of Dover) | | | | to | | | and | | 18 | each of 5.5 k.w. | Serrin |portable| | | (This apparatus was in use at Barfleur, 1893 |
| | | | | 6,500,000 | | | 60 | | | (550 revs.) | | steam, | | |to 1902.) |
| | | | | | | | | | | | | each 30| | | |
| | | | | | | | | | | | | i.h.p. | | | |
| Calais | 4 flash | 15 | .75 | 900,000 | 300 | 1 : 24 | 60 | 45 | 18 | do. | French | do. | 190 | 1883 |Fixed light apparatus, with revolving vertical |
| (Strait of Dover) | | | | | | | | | | | Service | | | | condensing prisms. |
| [Les Baleines (1882) | | | | | | | | | | | pattern | | | | |
| similar] | | | | | | | | | | | (1902) | | | | |
| | | | | | | | | | | | | | | | |
| Cap Gris-nez | Single flash | 5 |.10 to .14| 15,000,000| 300 | 1 : 4 | 60 | 45 | 18 and | do. | do. | Steam | 233 | 1899 |Twin optic, mercury rotation. |
| (Strait of Dover) | | | | to | | | to | | 28 | | | | | | (This light superseded a triple-flashing electric|
| | | | | 30,000,000| | | 120 | | | | | | | |light, with intermediate red flash, of the Calais |
| | | | | | | | | | | | | | | |type, established in 1885. The first installation |
| | | | | | | | | | | | | | | |of the electric light at this station was in 1869.)|
| La Canche | 2 flash | 10 |.10 to .14| 15,000,000| 300 | 1 : 4 | 30 | 45 | 14 and | do. | do. | do. | 174 | 1900 |Twin optic, mercury rotation. |
| (Strait of Dover) | | | | to | | | to | | 18 | | | | | | (This light superseded a fixed electric light |
| | | | | 30,000,000| | | 60 | | | | | | | |established in 1884.) |
| Cap de la Hève | Single flash | 5 |.10 to .14| 10,000,000| 300 | 1 : 4 | 60 | 45 | 18 and | De Meritens alternators | Improved | do. | 397 | 1893 | Mercury rotation. |
| (Havre, English | | | | to | | | to | | 28 | (550 revs.) | Serrin | | | | (The first installation of electric light at this|
| Channel) | | | | 20,000,000| | | 120 | | | | | | | |lighthouse was in 1863.) |
| [Île d'Yeu in the Bay | | | | | | | | | | | | | | | |
| of Biscay (1895) | | | | | | | | | | | | | | | |
| similar] | | | | | | | | | | | | | | | |
| Créac'h d'Ouessant | 2 flash | 10 |.10 to .14| 15,000,000| 300 | 1 : 4 | 60 | 45 | 18 and |2 De Meritens alternators,| French | do. | 225 | 1901 |Twin optic, mercury rotation. |
| (Ushant) | | | | to | | | to | | 28 | each of 5.5 k.w. | Service | | | | (This light superseded a double-flashing |
| [Barfleur (English | | | | 30,000,000| | | 120 | | | (550 revs.) | pattern | | | |electric light, similar to that now at Dunkerque, |
| Channel) 1903, La | | | | | | | | | | | (1902) | | | |established in 1888.) |
| Coubre (Bay of | | | | | | | | | | | | | | | |
| Biscay) 1905, and | | | | | | | | | | | | | | | |
| Belle Île (Bay | | | | | | | | | | | | | | | |
| of Biscay) 1903, | | | | | | | | | | | | | | | |
| similar] | | | | | | | | | | | | | | | |
| Penmarc'h (Phare | Single flash | 5 |.10 to .14| 15,000,000| 300 | 1 : 4 | 30 | 45 | 14 and | Two-phase Labour alter- | do. | do. | 197 | 1897 |Twin optic, mercury rotation. |
| d'Eckmühl) | | | | to | | | and | | 18 |nators (810 to 820 revs.) | | | | | |
| (Finistère) | | | | 30,000,000| | | 60 | | | | | | | | |
| Planier | Single flash | 5 |.10 to .14| 15,000,000| 300 | 1 : 4 | 30 | 45 |14 to 18| De Meritens alternators | do. | do. | 207 | 1902 |Twin optic, mercury rotation. |
| (near Marseilles) | | | | to | | | to | | | (550 revs.) | | | | | (This light superseded an electric light estab- |
| | | | | 30,000,000| | | 60 | | | | | | | |lished in 1881, showing a group of three white |
| | | | | | | | | | | | | | | |flashes separated by one red flash of the Calais |
|ITALY-- | | | | | | | | | | | | | | |type.) |
| Tino | 3 flash | 30 | 1.25 | Undeter- | 700 | 1 : 24 | 50 | 50 | 15 | do. | Berjot- | do. | 384 | 1885 |Eight panels of three lenses each, no mirror. |
| (Gulf of Spezia) | | | | mined. | | | 110 | | 25 | (830 revs.) | Serrin | | | | |
| | | | | | | | 200 | | 35 | | | | | | |
|AMERICA-- | | | | | | | | | | | | | | | |
| Navesink | Single flash | 5 | .08 | About | 700 | Nearly 1 : 2| Max. | 50 | 23 | Alternating dynamos | Modified | Oil, | 246 | 1898 |Mercury rotation. Bivalve of 165°. |
| (Entrance to New | | | | 60,000,000| | | 100 | | | (800 revs.) | Serrin | each | | | |
| York Bay) | | | | | | | | | | | (Ciolina)| 25 h.p.| | | |
| | | | | | | | | | | | | | | | |
|AUSTRALIA-- | | | | | | | | | | | | | | | |
| Macquarie | Single flash | 60 | 8 | 5,000,000 | 920 | 1 : 16 | 55 | 50 | 15 | De Meritens alternators | Serrin | Gas | 345 | 1883 |16-panel revolving apparatus, with 180° fixed |
| (Sydney, N.S.W.) | | | | | | | 110 | | 25 | (600 revs.) | | | | | mirror. |
+--------------------------+-----------------+-----+----------+-----------+----------+-------------+-------+----+--------+--------------------------+----------+--------+---------+-------+---------------------------------------------------+

TABLE VII.--_Typical Non-Electric Lighthouse Apparatus._

+----------------+-------------------+--------------+-------+--------+------------+---------+-------------+-------------+------------------+----------+-------+----------+-------------------------------------------------------------+
| | | | | | Candle- | | Ratio of | | | | | | |
| | | | | | Power in | | Angular | | | Service | Height| | |
| Name. | Locality. | Character- |Period.|Duration| Standard | Focal | Breadth of | Illuminant. | Burner. | Candle- | above | Year | Remarks. |
| | | istic. | | of | Candles |Distance | Panel to | | | power | High | Estab- | |
| | | | |Flashes.| (Service |of Lens.|Whole Circle.| | |of Burner.| Water.| lished.* | |
| | | | | | Intensity).| | | | | | | | |
+----------------+-------------------+--------------+-------+--------+------------+---------+-------------+-------------+------------------+----------+-------+----------+-------------------------------------------------------------+
| | | | Secs. | Secs. | | mm. | | | | | Feet. | | |
|Casquets | Channel Islands | 3 flash | 30 | 1.5 | 185,000 | 920 | 1 : 9 | Incandescent| "Matthews" 3-50 | 3300 | 120 | 1877 |Dioptric holophote, 126½° vertical angle; 3 sides of 3 |
| | | | | | | | | petroleum | mm. dia. mantles | | | | panels in each. |
| | | | | | | | | vapour | | | | | |
|Eddystone | South Devon | 2 flash | 30 | 1.5 | 292,000 | 920 | 1 : 12 | do. | do. | 3300 | 133 | 1882 |Biform apparatus, lens elements only, 92° vertical angle; |
| | | | | | | | | | | | | | 6 sides of 2 panels each. |
|Bishop Rock | Scilly Isles | 2 flash | 60 | 4.0 | 622,000 | 1330 | 1 : 10 | do. | do. | 3300 | 134 | 1886 |Biform apparatus, lens elements only, 80° vertical angle; |
| | | | | | | | | | | | | | 5 sides of 2 panels each. |
|Spurn Point | Yorkshire | Single flash | 20 | 1.5 | 519,000 | 1330 | 1 : 6 | do. | do. | 3300 | 120 | 1895 |Lens elements only, 80° vertical angle. |
|Lundy Island | Bristol Channel | 2 flash | 20 | .33 | 374,000 | 920 | Nearly 1 : 4| do. | do. | 3300 | 165 | 1897 |Mercury rotation, 4-panel bivalve. |
| | | | | | | | | | | | | | [St. Mary's Isle, Northumberland (1898), is similar.] |
|Pendeen | Cornwall | 4 flash | 15 | .25 | 190,000 | 920 | 1 : 8 | do. | do. | 3300 | 195 | 1900 |80° vertical angle lens, 2 sides of 4 panels each, mercury |
| | | | | | | | | | | | | | rotation. |
|Roker Pier | Sunderland | Single flash | 5 | .10 | 175,000 | 500 | Nearly 1 : 2| do. | "Chance" 55 mm. | 1200 | 83 | 1903 |Mercury rotation; univalve 164° in azimuth, with 164° |
| | | | | | | | | | dia. mantle | | | | dioptric mirror in rear. |
|Bell Rock | Near Firth of Tay | Red and white| 60 | .50 | 392,000 | 920 and | White about | do. | "Chance" 55 mm. | 1200 | 93 | 1902 |Combined hyper-radial and first-order light with back |
| | |flashes alter-| | | | 1330 | 1 : 9 | | dia. mantle | | | | prisms in white and mirrors in red. Revolves in 60 |
| | |nately every | | | | | red about | | | | | | secs. |
| | | 30 secs. | | | | | 1 : 2.2 | | | | | |[Holy Island, 1905 (Lamlash), similar, flash every 15 secs.] |
|Kinnaird's Head | Aberdeenshire | Single flash | 15 | .50 | 881,000 | 920 and | 1 : 2.2 | do. | do. | 2150 | 120 | 1903 |Composite apparatus; panels of 1330 mm. and 920 mm. |
| | | | | | | 1330 | | | | | | | focal distance; 2 faces. |
|Tarbet Ness | Dornoch Firth | 6 flash | 30 | .50 | 89,000 | 700 | 1 : 12 | do. | "Chance" 55 mm. | 1200 | 175 | 1892 |6 panels (lens) of 30° with 180° mirror. |
| | | | | | | | | | dia. mantle | | | | [Douglas Head (Isle of Man) similar.] |
|Sule Skerry | West of Orkneys | 3 flash | 30 | 1.0 | 378,000 | 1330 | 1 : 9 | do. | "Chance" 85 mm. | 2150 | 113 | 1895 |Equiangular lenses. |
| | | | | | | | | | dia. mantle | | | | |
|Pladda | South end of Arran| 3 flash | 30 | .50 | 597,000 | 1330 | 1 : 6 | do. | do. | 2150 | 130 | 1901 |3 equiangular lens panels with mirror in rear; side panels |
| | Island | | | | | | | | | | | | eccentric. |
| | | | | | | | | | | | | | [Hyskin Rocks (1904) similar.] |
|Tory Island | Co. Donegal | 3 flash | 60 | 3.0 | 17,000 to | 1330 | 1 : 6 | Coal Gas | Wigham, 108 jets | 2300 | 130 | 1887 |Triform apparatus, vertical angle of lenses 65°; 6 sides, |
| | | | | | 326,000 | | | | (maximum) | (max.) | | | one revolution in 6 minutes. The single flash from |
| | | | | | | | | | | | | | lens is divided by eclipsing burner into 3 flashes. |
|Fastnet | Co. Cork | Single flash | 5 | .17 | 750,000 | 920 | 1 : 4 | Incandescent| Irish pattern | 1200 | 160 | 1904 |Biform apparatus; 4 panels of 90° vertical angle and 90° |
| | | | | | | | | petroleum | 50 mm. mantle | | | | in azimuth; mercury rotation. |
| | | | | | | | | vapour | | | | | |
|Kinsale | do. | 2 flash | 10 | .25 | 460,000 | 920 | 1 : 6 | do. | do. | 1200 | 236 | 1907 |Biform apparatus, 3 sides each of 2 panels; vertical |
| | | | | | | | | | | | | | angle 96°; mercury rotation. |
| | | | | | | | | | | | | |[St. John's Point, Co. Down (1908) similar, period 7.5 secs.]|
|Howth Bailey | Dublin Bay | Single flash | 30 | 1.0 | 950,000 | 920 | 13 : 32 | do. |Irish pattern 3-50| 3300 | 134 | 1902 |Bivalve apparatus; panels of 147° in azimuth and 122° |
| | | | | | | | | | mm. dia. mantles | | | | vertical angle; mercury rotation. |
| | | | | / 1.0 | 70,000 | 920 | 1 : 8 | Oil | 6 wick | 480 | 164 | 1891 |\ |
| | | | || .50 | 180,000 | 920 | 1 : 8 | Incandescent| / 30 mm. dia. | 400 | 164 | 1895 | |The old first-order apparatus has been utilized in all |
|Chassiron | Bay of Biscay | Single flash | 10 || | | | | oil gas | | mantle | | | | | cases. |
| | | | || .70 | 360,000 | 920 | 1 : 8 | Incandescent| | 55 mm. dia. | 1300 | 164 | 1902 | | |
| | | | | \ | | | | acetylene | \ mantle | | | |/ |
|Cap d'Antifer | English Channel | Single flash | 20 | 1.0 | 400,000 | 1330 | 1 : 6 | Incandescent| French pattern | 2150 | 394 | 1894 |Mercury rotation, hyper-radial apparatus with reflecting |
| | | | | | | | | petroleum | 85 mm. mantle | | | | prisms. This is the only apparatus of this focal |
| | | | | | | | | vapour | | | | | distance on the French coast. |
|Île de Batz | Finistère | 4 flash | 25 | .37 | 200,000 | 920 | 1 : 8 | do. | do. | 2150 | 223 | 1900 |Group-flashing apparatus; 4 panels of 45°, with 180° |
| | | | | | | | | | | | | | mirror in rear; mercury rotation. |
|Ar'men | do. | 3 flash | 20 | .38 | 200,000 | 700 | 1 : 5 | do. | do. | 2150 | 94 | 1897 |Mercury rotation; 3 panels, mirror in rear. |
|Villefranche | Mediterranean | Single flash | 5 | .38 | 250,000 | 700 | 1 : 4 | do. | do. | 2150 | 229 | 1902 |Mercury rotation. |
|Île Vierge | Finistère | Single flash | 5 | .38 | 500,000 | 700 | 1 : 4 | do. | do. | 2150 | 252 | 1902 |Twin optic; mercury rotation. |
|Kennery Island | Bombay | 2 flash | 10 | .25 | 250,000 | 920 | Nearly 1:4 | do. |70 mm. dia. mantle| 1400 | 153 | 1902 |Mercury rotation; bivalve apparatus; 2 double-flashing |
| | | | | | | | | | | | | | 170° panels. |
|Cape Race | Newfoundland | Single flash | 7.5 | .30 | 1,100,000 | 1330 | 1 : 4 | do. | "Chance" 85 mm. | 2150 | 165 | 1907 |4 panels, vertical angle 121½°; mercury rotation. |
| | | | | | | | | | dia. mantle | | | | [Manora Point, Karachi, 1909, similar.] |
|Pachena Point | British Columbia | 2 flash | 7.5 | .44 | 220,000 | 920 | 1 : 8 | do. | do. | 2150 | .. | 1908 |Mercury rotation. 4 sides of 2 panels each. |
|Cape Hermes | Cape Colony | Single flash | 3 | .31 | 30,000 | 250 | 1 : 3 | do. | "Chance" 55 mm. | 1200 | 175 | 1904 |3 panels, vertical angle 150°; mercury rotation. |
| | | | | | | | | | dia. mantle | | | | |
|Hood Point | do. | 4 flash | 40 | .58 | 200,000 | 920 | 1 : 8 | do. | "Chance" 85 mm. | 2150 | 180 | 1895 |Mercury rotation; 4 panels of 45° in azimuth and 80° |
| | | | | | | | | | dia. mantle | | | | vertical angle, with catadioptric mirror in rear. |
|Cape Naturaliste| West Australia | 2 flash | 10 | .15 | 450,000 | 920 | About 1 : 3 | do. | do. | 2150 | 404 | 1904 |Mercury rotation; 2 lenses of 126½° in azimuth, with |
| | | | | | | | | | | | | | mirror of 107°. |
|Point Cloates | do. | Single flash | 5 | .30 | 300,000 | 700 | 1 : 3 | do. | do. | 2150 | 190 | 1909 |Mercury rotation; 3 panels, each 120° in azimuth and |
| | | | | | | | | | | | | | 133½° vertical angle. |
|Pecks Ledge |Connecticut, U.S.A.| 2 flash | 30 | .50 | 10,000 | 250 | 1 : 4 | do. |34 mm. dia. mantle| 300 | 54 | 1906 |Rotated on ball bearings. 2 lenses of 90° each and |
| | | | | | | | | | | | | | mirror. |
|Fire Island | New York, U.S.A. | Single flash | 60 | 4.0 | 250,000 | 920 | 1 : 8 | do. |55 mm. dia. mantle| 1000 | 167 | 1858 |Rotated on roller bearings. |
|Gray's Harbor |Washington, Pacific| Alternating | 5 | .20|White 10,000| 500 | .. | Oil | 3 wick | 160 | 122 | 1898 |Mercury rotation; one (red) lens of 170° in azimuth, re- |
| | Coast, U.S.A. | red and white| | | red 8,000 | | | | | | | | inforced by two 60° mirrors; one (white) lens of 60° in |
| | | flashes | | | | | | | | | | | azimuth. |
+----------------+-------------------+--------------+-------+--------+------------+---------+-------------+-------------+------------------+----------+-------+----------+-------------------------------------------------------------+

* The dates given are of the establishment of the optical apparatus.
In many cases incandescent burners have been installed at later
dates.

_English Colonies._--In Canada the coast lighting is in the hands of
the minister of marine, and in most other colonies the public works
departments have control of lighthouse matters.

_Other Countries._--In Denmark, Austria, Holland, Russia, Sweden,
Norway and many other countries the minister of marine has charge of
the lighting and buoying of coasts; in Belgium the public works
department controls the service.

In the Trinity House Service at shore lighthouse stations there are
usually two keepers, at rock stations three or four, one being ashore
on leave. When there is a fog signal at a station there is usually an
additional keeper, and at electric light stations a mechanical
engineer is also employed as principal keeper. The crews of
light-vessels as a rule consist of 11 men, three of them and the
master or mate going on shore in rotation.

The average annual cost of maintenance of an English shore lighthouse,
with two keepers, is £275. For shore lighthouses with three keepers
and a siren fog signal the average cost is £444. The maintenance of a
rock lighthouse with four keepers and an explosive fog signal is about
£760, and an electric light station costs about £1100 annually to
maintain.

A light-vessel of the ordinary type in use in the United Kingdom
entails an annual expenditure on maintenance of approximately £1320,
excluding the cost of periodical overhaul.

AUTHORITIES.--Smeaton, _Eddystone Lighthouse_ (London, 1793); A.
Fresnel, _Mémoire sur un nouveau system d'éclairage des phares_
(Paris, 1822); R. Stevenson, _Bell Rock Lighthouse_ (Edinburgh, 1824);
Alan Stevenson, _Skerryvore Lighthouse_ (1847); Renaud, _Mémoire sur
l'éclairage et le balisage des côtes de France_ (Paris, 1864); Allard,
_Mémoire sur l'intensité et la portée des phares_ (Paris, 1876); T.
Stevenson, _Lighthouse Construction and Illumination_ (London, 1881);
Allard, _Mémoire sur les phares électriques_ (Paris, 1881); Renaud,
_Les Phares_ (Paris, 1881); Edwards, _Our Sea Marks_ (London, 1884);
D. P. Heap, _Ancient and Modern Lighthouses_ (Boston, 1889); Allard,
_Les Phares_ (Paris, 1889); Rey, _Les Progrès d'éclairage des côtes_
(Paris, 1898); Williams, _Life of Sir J. N. Douglass_ (London, 1900);
J. F. Chance, _The Lighthouse Work of Sir Jas. Chance_ (London, 1902);
de Rochemont and Deprez, _Cours des travaux maritimes_, vol. ii.
(Paris, 1902); Ribière, _Phares et Signaux maritimes_ (Paris, 1908);
Stevenson, "Isle of May Lighthouse," _Proc. Inst. Mech. Engineers_
(1887); J. N. Douglass, "Beacon Lights and Fog Signals," _Proc. Roy.
Inst._ (1889); Ribière, "Propriétés optiques des appareils des
phares," _Annales des ponts et chaussées_ (1894); Preller, "Coast
Lighthouse Illumination in France," _Engineering_ (1896); "Lighthouse
Engineering at the Paris Exhibition," Engineer (1901-1902); N. G.
Gedye, "Coast Fog Signals," _Engineer_ (1902); _Trans. Int. Nav.
Congress_ (Paris, 1900, Milan, 1905); _Proc. Int. Eng. Congress_
(Glasgow, 1901, St Louis, 1904); _Proc. Int. Maritime Congress_
(London, 1893); J. T. Chance, "On Optical Apparatus used in
Lighthouses," _Proc. Inst. C.E._ vol. xxvi.; J. N. Douglass, "The Wolf
Rock Lighthouse," ibid. vol. xxx.; W. Douglass, "Great Basses
Lighthouse," ibid. vol. xxxviii.; J. T. Chance, "Dioptric Apparatus in
Lighthouses," ibid. vol. lii.; J. N. Douglass, "Electric Light applied
to Lighthouse Illumination," ibid. vol. lvii.; W. T. Douglass, "The
New Eddystone Lighthouse," ibid. vol. lxxv.; Hopkinson, "Electric
Lighthouses at Macquarie and Tino," ibid. vol. lxxxvii.; Stevenson,
"Ailsa Craig Lighthouse and Fog Signals," ibid. vol. lxxxix.; W. T.
Douglass, "The Bishop Rock Lighthouses," ibid. vol. cviii.; Brebner,
"Lighthouse Lenses," ibid. vol. cxi.; Stevenson, "Lighthouse
Refractors," ibid. vol. cxvii.; Case, "Beachy Head Lighthouse," ibid.
vol. clix.; _Notice sur les appareils d'éclairage_ (French Lighthouse
Service exhibits at Chicago and Paris) (Paris, 1893 and 1900); _Report
on U.S. Lighthouse Board Exhibit at Chicago_ (Washington, 1894);
_Reports of the Lighthouse Board of the United States_ (Washington,
1852, et seq.); British parliamentary reports, _Lighthouse
Illuminants_ (1883, et seq.), _Light Dues_ (1896), _Trinity House Fog
Signal Committee_ (1901), _Royal Commission on Lighthouse
Administration_ (1908); _Mémoires de la Société des Ingénieurs Civils
de France_, _Annales des ponts et chaussées_ (Paris); _Proc. Inst. C.
E._; _The Engineer_; _Engineering_ (_passim_). (W. T. D.; N. G. G.)

FOOTNOTES:

[1] A full account is given in Hermann Thiersch, _Pharos Antike,
Islam und Occident_ (1909). See also MINARET.

[2] In 1901 one of the lights decided upon in 1886 and installed in
1888--Créac'h d'Ouessant--was replaced by a still more powerful twin
apparatus exhibited at the 1900 Paris Exhibition. Subsequently
similar apparatus to that at Créac'h were installed at Gris-Nez, La
Canche, Planier, Barfleur, Belle-Île and La Coubre, and the old
Dunkerque optic has been replaced by that removed from Belle-Île.

[3] Both the Talais and Snouw light-vessels have since been converted
into unattended light-vessels.

[4] For the purposes of the mariner a light is classed as flashing or
occulting solely according to the duration of light and darkness and
without any reference to the apparatus employed. Thus, an occulting
apparatus, in which the period of darkness is greater than that of
light, is classed in the Admiralty "List of Lights" as a "flashing"
light.

[5] The Flamborough Head rocket was superseded by a siren fog signal
in 1908.

LIGHTING. Artificial light is generally produced by raising some body to a high temperature. If the temperature of a solid body be greater than that of surrounding bodies it parts with some of its energy in the form of radiation. Whilst the temperature is low these radiations are not of a kind to which the eye is sensitive; they are exclusively radiations less refrangible and of greater wave-length than red light, and may be called infra-red. As the temperature is increased the infra-red radiations increase, but presently there are added radiations which the eye perceives as red light. As the temperature is further increased, the red light increases, and yellow, green and blue rays are successively thrown off. On raising the temperature to a still higher point, radiations of a wave-length shorter even than violet light are produced, to which the eye is insensitive, but which act strongly on certain chemical substances; these may be called ultra-violet rays. Thus a very hot body in general throws out rays of various wave-length; the hotter the body the more of every kind of radiation will it throw out, but the proportion of short waves to long waves becomes vastly greater as the temperature is increased. Our eyes are only sensitive to certain of these waves, viz. those not very long and not very short. The problem of the artificial production of light with economy of energy is the same as that of raising some body to such a temperature that it shall give as large a proportion as possible of those rays which the eye is capable of feeling. For practical purposes this temperature is the highest temperature we can produce. As an illustration of the luminous effect of the high temperature produced by converting other forms of energy into heat within a small space, consider the following statements. If burned in ordinary gas burners, 120 cub. ft. of 15 candle gas will give a light of 360 standard candles for one hour. The heat produced by the combustion is equivalent to about 60 million foot-pounds. If this gas be burned in a modern gas-engine, about 8 million foot-pounds of useful work will be done outside the engine, or about 4 horse-power for one hour. If this be used to drive a dynamo for one hour, even if the machine has an efficiency of only 80%, the energy of the current will be about 6,400,000 foot-pounds per hour, about half of which, or only 3,200,000 foot-pounds, is converted into radiant energy in the electric arc. But this electric arc will radiate a light of 2000 candles when viewed horizontally, and two or three times as much when viewed from below. Hence 3 million foot-pounds changed to heat in the electric arc may be said roughly to affect our eyes six times as much as 60 million foot-pounds changed to heat in an ordinary gas burner.

Owing to the high temperature at which it remains solid, and to its great emissive power, the radiant body used for artificial illumination is usually some form of carbon. In an oil or ordinary coal-gas flame this carbon is present in minute particles derived from the organic substances with which the flame is supplied and heated to incandescence by the heat liberated in their decomposition, while in the electric light the incandescence is the effect of the heat developed by the electric current passed through a resisting rod or filament of carbon. In some cases, however, other substances replace carbon as the radiating body; in the incandescent gas light certain earthy oxides are utilized, and in metallic filament electric lamps such metals as tungsten or tantalum.

1. OIL LIGHTING

Vegetable and animal oils.

From the earliest times the burning of oil has been a source of light, but until the middle of the 19th century only oils of vegetable and animal origin were employed in indoor lamps for this purpose. Although many kinds were used locally, only colza and sperm oils had any very extended use, and they have been practically supplanted by mineral oil, which was introduced as an illuminant in 1853. Up to the latter half of the 18th century the lamps were shallow vessels into which a short length of wick dipped; the flame was smoky and discharged acrid vapours, giving the minimum of light with the maximum of smell. The first notable improvement was made by Ami Argand in 1784. His burner consisted of two concentric tubes between which the tubular wick was placed; the open inner tube led a current of air to play upon the inner surface of the circular flame, whilst the combustion was materially improved by placing around the flame a chimney which rested on a perforated gallery a short distance below the burner. Argand's original burner is the parent form of innumerable modifications, all more or less complex, such as the Carcel and the moderator.

A typical example of the Argand burner and chimney is represented in
fig. 1, in which the burner is composed of three tubes, d, f, g. The
tube g is soldered to the bottom of the tube d, just above o, and the
interval between the outer surface of the tube g and the inner surface
of the tube d is an annular cylindrical cavity closed at the bottom,
containing the cylindrical cotton wick immersed in oil. The wick is
fixed to the wick tube ki, which is capable of being moved spirally;
within the annular cavity is also the tube f, which can be moved
round, and serves to elevate and depress the wick. P is a cup that
screws on the bottom of the tube d, and receives the superfluous oil
that drops down from the wick along the inner surface of the tube g.
The air enters through the holes o, o, and passes up through the tube
g to maintain the combustion in the interior of the circular flame.
The air which maintains the combustion on the exterior part of the
wick enters through the holes m, with which rn is perforated. When the
air in the chimney is rarefied by the heat of the flame, the
surrounding heavier air, entering the lower part of the chimney,
passes upward with a rapid current, to restore the equilibrium. RG is
the cylindrical glass chimney with a shoulder or constriction at R, G.
The oil flows from a side reservoir, and occupies the cavity between
the tubes g and d. The part ki is a short tube, which receives the
circular wick, and slides spirally on the tube g, by means of a pin
working in the hollow spiral groove on the exterior surface of g. The
wick-tube has also a catch, which works in a perpendicular slit in the
tube f; and, by turning the tube f, the wick-tube will be raised or
lowered, for which purpose a ring, or gallery, rn, fits on the tube d,
and receives the glass chimney RG; a wire S is attached to the tube f,
and, bending over, descends along the outside of d. The part rn, that
supports the glass chimney, is connected by four other wires with the
ring q, which surrounds the tube d, and can be moved round. When rn is
turned round, it carries with it the ring q, the wire S, and the tube
f, thus raising or depressing the wick.

A device in the form of a small metallic disk or button, known as the
Liverpool button from having been first adopted in the so-called
Liverpool lamp, effects for the current of air passing up the interior
of the Argand burner the same object as the constriction of the
chimney RG secures in the case of the external tube. The button fixed
on the end of a wire is placed right above the burner tube g, and
throws out equally all round against the flame the current of air
which passes up through g. The result of these expedients, when
properly applied, is the production of an exceedingly solid brilliant
white light, absolutely smokeless, this showing that the combustion of
the oil is perfectly accomplished.

The means by which a uniformly regulated supply of oil is brought to
the burner varies with the position of the oil reservoir. In some
lamps, not now in use, by ring-formed reservoirs and other expedients,
the whole of the oil was kept as nearly as possible at the level of
the burner. In what are termed fountain reading, or study lamps, the
principal reservoir is above the burner level, and various means are
adopted for maintaining a supply from them at the level of the burner.
But the most convenient position for the oil reservoir in lamps for
general use is directly under the burner, and in this case the stand
of the lamp itself is utilized as the oil vessel. In the case of fixed
oils, as the oils of animal and vegetable origin used to be called, it
is necessary with such lamps to introduce some appliance for forcing a
supply of oil to the burner, and many methods of effecting this were
devised, most of which were ultimately superseded by the moderator
lamp. The Carcel or pump lamp, invented by B. G. Carcel in 1800, is
still to some extent used in France. It consists of a double piston or
pump, forcing the oil through a tube to the burner, worked by
clockwork.

A form of reading lamp still in use is seen in section in fig. 2. The
lamp is mounted on a standard on which it can be raised or lowered at
will, and fixed by a thumb screw. The oil reservoir is in two parts,
the upper ac being an inverted flask which fits into bb, from which
the burner is directly fed through the tube _d_; _h_ is an overflow
cup for any oil that escapes at the burner, and it is pierced with
air-holes for admitting the current of air to the centre tube of the
Argand burner. The lamp is filled with oil by withdrawing the flask
ac, filling it, and inverting it into its place. The under reservoir
_bb_ fills from it to the burner level ee, on a line with the mouth of
ac. So soon as that level falls below the mouth of _ac_, a bubble of
air gets access to the upper reservoir, and oil again fills up bb to
the level _ee_.

The moderator lamp (fig. 3), invented by Franchot about 1836, from the
simplicity and efficiency of its arrangements rapidly superseded
almost all other forms of mechanical lamp for use with animal and
vegetable oils. The two essential features of the moderator lamp are
(1) the strong spiral spring which, acting on a piston within the
cylindrical reservoir of the lamp, serves to propel the oil to the
burner, and (2) the ascending tube C through which the oil passes
upwards to the burner. The latter consist of two sections, the lower
fixed to and passing through the piston A into the oil reservoir, and
the upper attached to the burner. The lower or piston section moves
within the upper, which forms a sheath enclosing nearly its whole
length when the spring is fully wound up. Down the centre of the upper
tube passes a wire, "the moderator," G, and it is by this wire that
the supply of oil to the burner is regulated. The spring exerts its
greatest force on the oil in the reservoir when it is fully wound up,
and in proportion as it expands and descends its power decreases. But
when the apparatus is wound up the wire passing down the upper tube
extends throughout the whole length of the lower and narrower piston
tube, obstructing to a certain extent the free flow of the oil. In
proportion as the spring uncoils, the length of the wire within the
lower tube is decreased; the upward flow of oil is facilitated in the
same ratio as the force urging it upwards is weakened. In all
mechanical lamps the flow is in excess of the consuming capacity of
the burner, and in the moderator the surplus oil, flowing over the
wick, falls back into the reservoir above the piston, whence along
with new supply oil it descends into the lower side by means of
leather valves a, a. B represents the rack which, with the pinion D,
winds up the spiral spring hard against E when the lamp is prepared
for use. The moderator wire is seen separately in GG; and FGC
illustrates the arrangement of the sheathing tubes, in the upper
section of which the moderator is fixed.

Mineral oils.

As early as 1781 the idea was mooted of burning naphtha, obtained by the distillation of coal at low temperatures, for illuminating purposes, and in 1820, when coal gas was struggling into prominence, light oils obtained by the distillation of coal tar were employed in the Holliday lamp, which is still the chief factor in illuminating the street barrow of the costermonger. In this lamp the coal naphtha is in a conical reservoir, from the apex of which it flows slowly down through a long metal capillary to a rose burner, which, heated up by the flame, vaporizes the naphtha, and thus feeds the ring of small jets of flame escaping from its circumference.

It was in 1847 that James Young had his attention drawn to an exudation of petroleum in the Riddings Colliery at Alfreton, in Derbyshire, and found that he could by distillation obtain from it a lubricant of considerable value. The commercial success of this material was accompanied by a failure of the supply, and, rightly imagining that as the oil had apparently come from the Coal Measures, it might be obtained by distillation from material of the same character, Young began investigations in this direction, and in 1850 started distilling oils from a shale known as the "Bathgate mineral," in this way founding the Scotch oil industry. At first little attention was paid to the fitness of the oil for burning purposes, although in the early days at Alfreton Young attempted to burn some of the lighter distillates in an Argand lamp, and later in a lamp made many years before for the consumption of turpentine. About 1853, however, it was noticed that the lighter distillates were being shipped to Germany, where lamps fitted for the consumption of the grades of oil now known as lamp oil were being made by Stohwasser of Berlin; some of these lamps were imported, and similar lamps were afterwards manufactured by Laidlaw in Edinburgh.

In Pennsylvania in 1859 Colonel E. L. Drake's successful boring for petroleum resulted in the flooding of the market with oil at prices never before deemed possible, and led to the introduction of lamps from Germany for its consumption. Although the first American patent for a petroleum lamp is dated 1859, that year saw forty other applications, and for the next twenty years they averaged about eighty a year.

English lamp-makers were not behind in their attempts to improve on the methods in use for producing the highest results from the various grades of oil, and in 1865 Hinks introduced the duplex burner, while later improvements made in various directions, by Hinks, Silber, and Defries led to the high degree of perfection to be found in the lamps of to-day. Mineral oil for lamps as used in England at the present time may be defined as consisting of those portions of the distillate from shale oil or crude petroleum which have their flash-point above 73° F., and which are mobile enough to be fed by capillarity in sufficient quantity to the flame. The oil placed in the lamp reservoir is drawn up by the capillarity of the wick to the flame, and being there volatilized, is converted by the heat of the burning flame into a gaseous mixture of hydrogen and hydrocarbons, which is ultimately consumed by the oxygen of the air and converted into carbon dioxide and water vapour, the products of complete combustion.

To secure high illuminating power, together with a smokeless flame and
only products of complete combustion, strict attention must be paid to
several important factors. In the first place, the wick must be so
arranged as to supply the right quantity of oil for gasification at
the burner-head--the flame must be neither starved nor overfed: if the
former is the case great loss of light is occasioned, while an excess
of oil, by providing more hydrocarbons than the air-supply to the
flame can completely burn, gives rise to smoke and products of
incomplete combustion. The action of the wick depending on the
capillary action of the microscopic tubes forming the cotton fibre,
nothing but long-staple cotton of good quality should be employed;
this should be spun into a coarse loose thread with as little twist in
it as possible, and from this the wick is built up. Having obtained a
wick of soft texture and loose plait, it should be well dried before
the fire, and when put in position in the lamp must fill the
wick-holder without being compressed. It should be of sufficient
length to reach to the bottom of the oil reservoir and leave an inch
or two on the bottom. Such a wick will suck up the oil in a regular
and uniform way, provided that the level of the oil is not allowed to
fall too low in the lamp, but it must be remembered that the wick acts
as a filter for the oil, and that if any sediment be present it will
be retained by and choke the capillaries upon which the action of the
wick depends, so that a wick should not be used for too long a time. A
good rule is that the wick should, when new, trail for 2 in. on the
bottom of the oil vessel, and should be discarded when these 2 in.
have been burnt off.

When the lamp is lighted the oil burns with a heavy, smoky flame,
because it is not able to obtain sufficient oxygen to complete the
combustion, and not only are soot flakes produced, but products of
incomplete combustion, such as carbon monoxide and even petroleum
vapour, escape--the first named highly injurious to health, and the
second of an offensive odour. To supply the _necessary amount of air_
to the flame, an artificial draught has to be created which shall
impinge upon the bottom of the flame and sweep upwards over its
surface, giving it rigidity, and by completing the combustion in a
shorter period of time than could be done otherwise, increasing the
calorific intensity and thus raising the carbon particles in the
flame to a far higher incandescence so as to secure a greater
illuminating power. This in practice has been done in two ways, first
by drawing in the air by the up-suck of the heated and expanded
products of combustion in a chimney fitted over the flame, and
secondly by creating a draught from a small clockwork fan in the base
of the lamp. It is necessary to break the initial rush of the draught:
this is mostly effected by disks of perforated metal in the base of
the burner, called _diffusers_, while the metal dome which surrounds
and rises slightly above the wick-holder serves to deflect the air on
to the flame, as in the Wanzer lamp. These arrangements also act to a
certain extent as regenerators, the air passing over the heated metal
surfaces being warmed before reaching the flame, whilst disks, cones,
buttons, perforated tubes, inner air-tubes, &c., have been introduced
to increase the illuminating power and complete the combustion.

TABLE I.

+---------------+------------------+------------------+-------------------+
| | | Grains of Oil | |
| | | per candle-power |Total Candle-power.|
| Type. | Name. | per hour. | |
| | +---------+--------+---------+---------+
| | |American.|Russian.|American.| Russian.|
|---------------+------------------+---------+--------+---------+---------+
| /| Veritas, 60-line | 64.5 | 112.5 | 122.5 | 78 |
| | | " 30-line | 42.5 | 50. | 60 | 60 |
| | | " 20-line | 43.75 | 58.5 | 40 | 35 |
|Circular wick| | Ariel, 12-line | | | | |
| | | center draught | 52.8 | 70.9 | 18 | 18 |
| | | Reading, 14-line | 97.9 | 85.4 | 12 | 12 |
| | | Kosmos, 10-line | 63.9 | 97.2 | 9 | 9 |
| \| Wizard, 15-line | 56.9 | 51.3 | 18 | 19 |
| /| Wanzer, no glass | 42.6 | 48.3 | 17 | 17 |
|Flat wick, | | Solid slip, gauze| | | | |
| single | | and cone | 84.4 | 84.4 | 8 | 8 |
| | | Old slip, fixed | | | | |
| \| gauze | 60.9 | 89.3 | 7 | 7 |
|Flat wick, /| Feeder wick | 56.2 | 55.7 | 20 | 22 |
| duplex \| Ordinary | 51.2 | 46.6 | 20 | 22 |
+---------------+------------------+---------+--------+---------+---------+

American oil--Sp. gr. 0.7904; flash-point, 110°F. Russian oil--Sp.
gr. 0.823; flash-point, 83° F.

According to Sir Boverton Redwood, duplex burners which give a flame
of 28 candle-power have an average oil consumption of 50 grains per
candle per hour, while Argand flames of 38 candle-power consume about
45 grains of oil per candle per hour. These figures were obtained from
lamps of the best types, and to obtain information as to the
efficiency of the lamps used in daily practice, a number of the most
popular types were examined, using both American and Russian oil. The
results obtained are embodied in Table 1. The first noteworthy point
in this table is the apparent superiority of the American over Russian
oil in the majority of the lamps employed, and there is no doubt that
the bulk of the lamps on the market are constructed to burn American
or shale oil. A second interesting point is that with the flat-flame
lamps the Russian oil is as good as the American. We have Redwood's
authority, moreover, for the fact that after prolonged burning the
Russian oil, even in lamps least suited to it, gives highly improved
results. Although the average consumption with these lamps is close
upon 60 grains per candle with American oil, yet some of the burners
are so manifestly wasteful that 50 grains per candle-power per hour is
the fairest basis to take for any calculation as to cost.