I04 



NATURE 



\ytme 2, 1887 



disaster (such as that which befell the Calf Rock Light a 

 few years later) were to be avoided. It had been suggested 

 to destroy the reef by blasting, as it had been persistendy 

 suggested since 1844 to remove the Goodwin Sands. But 

 in either case not only would such a thing be impractic- 

 able on account of the enormous expenditure of money 

 and time ; but also there is a positive advantage for navi- 

 gation in retaining a lighthouse or a lightship on these 

 sites. The new Eddystone tower replacing that of 

 Smeaton, which had made the name memorable for 123 

 years, has an elevation from lantern-centre to high water 

 of 133 feet, commanding a horizon of seventeen and a half 

 nautical miles (to a vessel's deck). The corresponding 

 horizon of the old tower was about fourteen miles, 

 with an elevation of 72 feet. The extended range is 

 ample for all maritime needs. The structure contains 

 63,020 cubic feet, or 4668 tons, of Cornish and Dalbeattie 

 granite. The tower springs from a solid cylinder of granite 

 about 45 feet in diameter and 20 feet high, set indissolubly 

 on the rock. The mean diameter is about 30 feet. It is 

 solid up to 25 1 feet above high water, except as regards 

 space for a water-tank which holds 3500 gallons. It has 

 seven chambers for stores and keepers' use, and a room for 

 exhibiting a small light 15° in azimuth to denote a danger 

 called Hand Deeps. These chambers all have a diameter 

 of 14 feet. There are besides two others below them of 

 less size. Two massive fog-bells are fixed under the 

 lantern-gallery. Very little inflammable material is used. 

 The doors, window-frames, and other fittings are of gun- 

 metal, and every modern resource has been employed to 

 make the building weather-proof and enduring, and to 

 insure the comfort of the three men confined in it, and 

 the unfailing exhibition of the powerful light which crowns 

 it. The time occupied in the work was about three years 

 and a half, the cost less than ^80,000. 



It is unnecessary to refer to the numerous land towers 

 erected by lighthouse authorities during the half century, 

 because these, being reared for the most part on cliffs, and 

 little exposed to stress of sea, present no difficulty of 

 construction or novelty of type. 



All the towers hitherto named are of stone, but iron 

 has not been overlooked as in some circumstances a 

 practicable material for a sea structure. The designs of 

 the late Mr. Alexander Gordon, C.E., in cast and wrought 

 iron, for the towers of several West Indian and South 

 African lights are well worthy of attention, as are also 

 those of Messrs. Grissell for Russia, &c. ; and, more 

 recently, the tall iron towers designed and made by 

 Messrs. Chance, of Birmingham, for Australasian sites, 

 are not less remarkable. At home, the Fastnet may be 

 taken as a successful instance of the application of iron. 

 The rock so called is four miles south-west by west of 

 Cape Clear, and has been symboHsed as the " Tear-drop of 

 Ireland." being the " last of the old country seen by emi- 

 grants.' This tower was begun in 1848, and completed 

 in 1853. It is composed of a casing of cast-iron plates 

 with a central column and girder floors, forming five 

 chambers 12 feet high. The lowest story is partly 

 filled in with masonry, leaving space for a coal-vault. The 

 other stories are lined with brick. The internal diameter 

 of the tower is 12 feet, the height from base to gallery 

 64 feet. The focal plane is 148 feet above the sea. 

 The cost of the work was ^19,000. The engineer and 

 designer was the late Mr. George Halpin. 



The lightships established in British waters are of great 

 interest. There are now about seventy-five, sixty being 

 on the English coast, of which the larger number date 

 from since 1837. Several of these peculiarly English 

 vessels were placed on their stations in the last century, 

 the historical Nore, for instance, in 1732. 



Iron had been in use for light-vessels in the Mersey 

 before 1856. In 1843 it had been discussed by the Trinity 

 House as a possible material, but was not then deemed 

 desirable. The first Trinity iron vessel was stationed in 



1857 on the Goodwin Sands, the next in Cardigan Bay 

 in i860. The usual length of a Trinity hghtship is 80 

 feet when constructed of wood, and about 90 feet 

 when of iron, the width is 21 feet, the average 

 tonnage 155 to 160 tons when of wood, and 180 tons 

 when of iron. The focal plane of a light is generally 

 38 feet above high water. The cost averages ^3600 

 for wood, and ^5000 or ;^55oo for iron. An immense 

 service is rendered by these modest and vigilant 

 sentinels of the deep which surround our coasts in 

 positions impossible for a lighthouse, and for the most 

 part close to the dangers of which they give warning, or 

 to the channel of approach which they indicate. It has 

 long been' proposed to connect these vessels, as also rock 

 and pile lighthouses, with the shore, and (in some cases) 

 wilh one another, by an electric cable ; and a Committee 

 is now engaged on the subject. In this way com- 

 munications may be made as to the safety and require- 

 ments of the station, and as to the passing shipping, and 

 to wrecks and other casualties, though it is doubtful 

 whether reports on the last heads are a proper addition to 

 the functions of a light-keeper, or one that is likely to be 

 satisfactory in the result to the persons concerned. 



A curious and ingenious plan of combining the light- 

 house with the lightship was conceived by Mr. George 

 Herbert in 1853, and much discussed and recommended 

 at the time. On the assumption that the form of a ship 

 is not the best for a stationary floating body, he proposed 

 a circular vessel, moored from its centre of gravity, and 

 supporting a central tower of about 40 feet high, with 

 lantern, gallery, &c., of the usual kind. A candlestick 

 set in a wash-tub may not be too familiar an illustration. 

 A position north of the Stones Rock, on the Cornish 

 coast, was suggested, at an expense of about ^10,000. 

 The Trinity House did not adopt this plan, but in 1859 

 two beacon buoys on the same principle were successively 

 placed off the Stones, and after a few weeks' service were 

 driven from their moorings and destroyed. 



The use of screw piles for the foundation of a lighthouse 

 in sand was first demonstrated at Fleetwood in 1840, and 

 Maplin in 1841, and afterward at the Chapman, Gunfleet, 

 and other stations. The method is that of Alexander 

 Mitchell, improved by Mr. George Wells, who has erected 

 many such structures in various shallow seas. 



The lantern, that is the framework of glass and metal, 

 which contains the illuminating apparatus, whether in land 

 or floating lights, has been much modified during the past 

 fifty years. At the accession the lantern of a first-class 

 light was from 10 to 12 feet in diameter, with perhaps 

 8 feet of glazing in polygonal panes. The bars were 

 heavy and intercepted much light, the ventilation defective, 

 the construction more or less weak and unequal. Succes- 

 sive improvements have been effected by the engineers of 

 the Trinity House and Northern Lights Commission, and 

 by Chance, of Birmingham. In its highest type, that of 

 Sir James Douglass, as in the Bishop Rock example, the 

 lantern of to-day for a first order lighthouse is well worthy 

 of the perfected optical instrument which it protects. It 

 has a diameter of 14 feet between the glass surfaces, 

 a height of glass of 15 feet, and a height from base to 

 vane of about 32 feet. It is cylindrical in form, with 

 solid gun-metal bars, helically inclined and of wedge- 

 like section towards the flame, comprising sixty-four 

 openings of diamond and sixty-four of triangular shape. 

 The polished plate-glass is three-eighths of an inch thick, 

 and bent accurately to fit in these openings. Nine-tenths 

 of the incident light from the lamp is transmitted through 

 this glass. Not more than yj}^ of light is stopped by the 

 lantern framing. Thus the maximum of stability and the 

 minimum obstruction of the rays are obtained. At the 

 same time every expedient to promote perfect ventila- 

 tion, from the tubes of Faraday to the longitudinal valves 

 and the roof-cylinders of Douglass, has been adopted, 

 this being indispensable for the combustion of the great 



