seaward of the light should not be employed except when the danger is in the near vicinity of the light. Outlying dangers require marking by a light placed on the danger or by a floating lightin its vicinity. 9. ILLUMINATED Buoys.-Gas Buoys. Pintsch's oil gas has been the most efficient system of coast lighting, since the beams of light from the most powerful electric lighthouse are frequently entirely dispersed and absorbed by the particles of moisture, forming a sea fog of even
in use for the illumination of buoys since 1878. In 1883 an automatic moderate density, at occulter was perfected, worked by the gas passing from the reservoir a distance of less to the burner. The lights placed on these buoys burn continuously than a i m. from the for three or more months. The buoys and lanterns are made in shore. The careful 4 "'V H various forms and sizes. The spar buoy (fig. 50) may be adopted for experi me n ts and situations where strong tides or currents pre- scientific research vail. Oil gas l1g hts are frequently fitted to which have been de- M 5 Courtenay whistling (fig. 51) and bell buoys. voted to the subject ' ~ » ¢-3 In the ordinary type off gas buoy lantern of coast fog-signal-53 the burner emp oyed is o the mu tip e-jet, ling have produced 1" ', Argand ring, or incandescent type. Incan- much that is useful L / descent mantles have been applied to b uoy and valuable to the Q lights in France with st;ccessfu results. SIIIC? mariner, but unfor'!:y 1906, and more recent y the same system 0 tunatelythe practical r illumination has been adopted in England results so far have B im and other ccéuntqieg, The lensei employed not been so satis- T, gi I—* are of cylin rica ioptric fixed- ight form factory as might be , 1 usually 100 mm. to 300 mm. diameter. Some desired, owing to (I) 52; of the largest types of gas-buoy in use on the the very short range iff-"T 32522 D 112 Frerich coasg haf/elan elevation frpm walter of the most powerful " T "Q" "" r eve to the oca p ane o over 26 t. wit a signals yet produced m beam intensity of more than 1000 candles. under certain un- F f ~ "'" A large gas-buoy with an elevation of 34 ft. favourable acoustic B jjjjjjjjjj V to the focal plane was placed at the entrance conditions of the ' ' F Elo the (gironde ind 190135 It hiishan Encan- atmosphere, (2) the '*°: 4, escent urner an ex 1 its a ig t o over difficulty experi- . .L ~ '»1§ , ..» W y 1500 candles. Qil gas forms the most trust- enced by the mariner V:f F CP ' worthy and efficient 1llum1na11t for buoy pur- in Judging at any 2 Q Q 2 poses yet introduced, and the system has time how far the, !":', ,, E g 5 been largely adopted by lighthouse and atmospheric condi- N535 Cb h3.X'bOL11' authorities. tigng are against him "M Cb There are now over 2000 buoys fitted with in listening for the, . iiilhgas appiaratgsijin addition to 600 beacons, (Expected sggnag, and FIG- 51- couffenaxlgs Automatic Whlsfllng ig t-vesse s an oats. 3 the di Cu ty in OY-Electriq Lit l§ uoiys.~Buoys have been locating the position A, Cylinder, 27 ft. H, Air (compressed wanr L¢v¢| fitted with electric 1ght, both fixed and of a sound signal by 6 in. long. outlet tube to - - occulting. Six electrically l1t spar-buoys were phonic observations. B, Mooring shackle. whistle. W Ib d laid dcgwn in th§ 8(gedr'ie]y channel, gIew Yorlé Bellé and Gémgs are C, Rudder. I, (iomprsfsed air ine e ower ay, in I . ese were 1 urrllnate theol estan, gener- D, Buoy. et to uoy. S, .ée| by Ioo candle-power Swan lamps with con- ally speaking, the E, Diaphragm. K, Manhole. G hi id tinuous current supplied by cable from a least efficient forms F, Ball valves. L, Steps. as f ff power station on shore. The wear and tear of fog signals. Under G, Air inlet tubes. N, Whistle. of the cables caused considerable trouble and very favourable expense. In 1895 alternating current was acoustic conditions the sounds are audible at considerable ranges. On introduced. The installation was superseded the other hand, 2-ton bells have been inaudible at distances of a few by gas lit buoys IH 1904; hundred yards. The 1893 United States trials showed that a bell 1 Acfitylege andtO1l Lfghted {3uo§ s.-Acety- weighing 4000 Ib struck by a 450 lb hammer was heard at a distance ene as een ex ensive y emp oye
for the lighting of buoys in Canada V
e and in the United States; to a less
extent it has also been adopted in
§§ 2§§ ..§ °“§§ '§§§ ia ffthwhili i°h“é 1 C i°°°"° ' " x 1 ' ¢|. '77 .
1 Qaiazfgs.g;;.;f.s;;?d;;;€.E;h;, § ....sg&.., V called high pressure system 1n w ic, is
urified acetylene 15 held in solution R '
i)n a high pressure gasholder filled ' § §
with asbestos composition saturated g 5
| with acetone, have been employed § 'Q
1, for illuminating buoys and beacons. §
P - . Wigham oil lam s are also used to §
a limited extent(f§ i>r bfuoy lighting., §
E | Bell Bu0ys.— ne ormo capper M, ,
t 4 actuated byhthe roll of the bpoy Ill i!l! @i |!!| L, ' (shown in . 52) consists o a .:.. " 'W M ~ '4 “@, g, ¢..* Q-§ ' °"' 1 J, , hardened steei ball placed in a hori- Si; ' it* -" LT' - - °" zontal phosphor-bronze cylinder ' 1, / 'ir
Li provided with rubber buffers. 553, 1 ' I; (' II ~ |f| ' 7 Al 5 ' I
Three of these cylinders are arranged ? : Y., around the mouth of the fixed bell, »?, *f2, ... N. ., g{ #3 ¥~s ~, » » FIG. 50.-Spar Gas which is struck by the balls rolling “" BUOY- backwards and forwards as the tx WN." 'Q
buoy mc;1ves.uAn0]t1he1{1 form of bell V
h ', n ists of a fixe be wit t ree or more
cT§ p;ers placed externally which strike the g,
bell when the buoy rolls.
ro. Foo S1GNALs.-The introduction of coast fog
signals is of comparatively recent date. They were, until the middle of the 19th century, practically unknown except so far as a few isolated bells and guns were concerned. The increasing demands of navigation, and the application of steam power to the propulsion of ships resulting 1n an1ncrease of their speed, drew attention to the necessity of proylding suitable signals as aids to navigation during fog and mist. In t1m€S of fog the mariner can expect no certain assistance from even FIG. 52.-Buoy Bell.
of 14 m. across a gentle breeze and at over 9 m. against a Io-knot breeze. Bells are frequently used for beacon and buoy signals, and in some cases at isolated rock and other stations where there is insufficient accommodation for sirens and horns, but their use is
being gradually discontinued in this country for situations where a