LIGHT-HOUSE. 



«ome immediately over the others, as the figure would in- 

 fer, but they break j.iiiit with each otlicr to give every 

 part of the foliJ an equal (Irenjjth. Above the folid, a 

 new fyilem of building was necclTanly adopted: the lower 

 courfes were coinpofed of Portland (loncs to fill up the 

 centre, and moor iiones, as being nioie durable, to make the 

 outfide. The whole of the upper works are of moor llone ; 

 and dovetailinjj hci'g no longer pradlicable, the Hones :re 

 united by iron cramps and joggles, as Ihevvn in^^. 7, which 

 is a plan of the upper or bed-room M. Each ftone is here feen 

 to have an iron crump to join it to its neighbour, and has a 

 fmall marble joggle to unite it with tliat above it. The ver- 

 tical joints are rendered impervious to water, by cutting a 

 notch between every two adjuceut Hones, fo that when they 

 come togeliier it forms a hole of a lozenge fliape, and a 

 piece of llune being put dovyn into this hole with mortar, 

 makes a perfcA joint, at the fame time increafing the bond 

 of the iiones. This kind of joint is partly feen in_y?f. 8, at 

 n, but one-half is hid by the iron cramps r, r, extending 

 over every joint. In this figure they are feen inclined, tliat 

 they may take firmer hold of the ftcnes s, s, forming the 

 fides of the apertures T, for the window. The (lones of the 

 different floors arc dovetailed together, as in ^/fj'j. 5 and 7, 

 and are rather arched on the lower fide, as flicwn in Jig. 2. 

 To retain the thrull of thefe arches, every courfe trom vvhich 

 a fioor fpriiigs, is bound by an eiidlefs chain inlaid in the 

 fione work, as in Jir. j, and run in folid with lead. The 

 chain is fiiewn enlarged in Ji^. 6. Fig. 7. is a plan of the 

 bed-room M, (liewing the diljiohtion of ihe three cabin beds 

 i, I, lit, with a window between each. The dark ipot m is the 

 fmoke funnel, and n is the place for a clock. — The reader is 

 now tolerably well acquainted with the conl'.ruftion of Mr. 

 Smeatoii's light-lioufe ; but in fudi a peculiarly expofed 

 fituation, every trifling operation was attended with diffi- 

 culty, and demanded thought and ingenuity to devife the 

 means of accomplilliing it. On this account we iliall briefly 

 follow Mr. Smeatoii through his narrative, though it relates- 

 circumllances which, if recorded in the account of a com- 

 mon building, wijuld appear impertinently minute. The 

 feaibn when Mr. Smeaton firll took up the bufmefs of the 

 liglit-houfe not being favourable for a vifit to the rock, he 

 did not attempt it till April 1756, before which time he had 

 deligned the general plinciplcs of the building. He fcund 

 upon the rock the irons of both the former erections, and 

 fcveral of the moor Rones of the late building lying in the 

 gut, wiiicii was a narrow channel of twelve feet deep be- 

 tween the houfe rock, and a reef of rocks to the well ward, 

 in which channel the boats coming to the houfe could lie 

 in fair weatlier. His firil vifit was employed in obferva- 

 tions on the rock, ancFin experiments of the time rcquilite to 

 drill and pick holes cf a certain dimenfion, that he might 

 elliraatc the time necelTary to complete the work on the 

 rock. In fucceeding voyages he took dimenfions of every 

 part to enable him to make an accurate model, to which he 

 could ada'Jt a model of the intended building. The unfa- 

 vourable days at fea were employed on fliore in examining 

 the (lone in the country round, a convenient fituation for a 

 work-yard, &c. The dimenfions of the rock were taken by 

 the foliov/ing means : He fiiced up the circle of ?. theodolite, 

 with its index, in the centre of tlie rock, and levelled it 

 with ti e fpirit-level ; a light rod was fixed to the index, 

 long enough, when turned round, to reach all parts of the 

 rock ; it was provided witli a fpirit-level to (hew when it 

 Hood horizontal. It is obvious that this rod, when turned 

 round, would defcribe a horizontal plane, and the depth of 

 any pcint of the rock beneath this plane was afcertained by 

 a rod fel u]) vertically upon the point in quelUon, and ap- 



plying the horizontal ruler to it. The divilioiis on the ver- 

 tical rod fliewed the depth ; and tite divifiou of the horr- 

 zontal ruler fliewed the diitance from tlie centre, and the 

 degrees of the theodolite circle pointed out the direclion. 

 By thefe means the jjofilion and altitude of thirty-two 

 principal points were obtained, which were well marked 

 upon the rock, and a line being ftrctched from one of thelo 

 points to another, pave the means of determining the pt»- 

 fition of the iron ftanchioi;S, or any thing elle vshieh was 

 remarkable. Having thi:s, ill ten voyages, made all tl.«; 

 nccedary obfervations on the rock, and determined upon re- 

 gulations for the management of the work, he returned to 

 i^ondon, and, in his way, vifited the various ftone quarries in 

 Devonlhire, and the illes of Portland and Purbeck. He 

 was employed, till the month of July, in making cxaA mo- 

 dels of the building, when he returned to Plymouth, where 

 he found a velfel, the Neptune Bufs, whi. h had been fitted 

 up for exhibitini; a temporary light during the period of 

 rebui'diiig the hoiifc. From fome mifundcrC.anding be- 

 tween the Board of Trinity and the proprietors, this veffel 

 was not eu-.ployed in this manner, but was devoted to Mr. 

 Smealon's ufe, who immediately began tlic work.s upon the 

 rock ; mooring the Bufs near the rock to ferve as a retrejrt 

 for the workmen, who were frequently driven off by the 

 waves. In the month of September the three Icwer ll^ps of 

 the rock wore completed, and the upper ones in a Ihite 

 of great fur wardnefs ; after which time, bad weather pre- 

 vented much more being done that year, and In November 

 the Bufs left her moorings to return to Plymoutb, in which 

 voyage (lie was driven to fea, and narrowly efcapcd (hip- 

 wreck. Thus concluded the i perations of the year 1756.. 

 The winter feafon was pafTed in preparing ftone work on 

 (hore, m building boats, and, by Mr. Smeaton, in a long 

 and valuable ieries of cxperin.ents on the different kinds ct 

 cements, which could be applied to the building. 



In May 1757, the Bufs was carried out and moored, and 

 on the 1 2th of June the lowell and firll Hone was kid in its 

 place ; from the great uncertainty of the weather every ftone 

 was fo contrived, that it was of itfclf in a condition to rcfiit 

 the wafh of the fea,even when it was immediately laid, and be- 

 fore it was hardened. For this pnr^ofe, eath (lone had one or 

 two holes drilled through it before it left the work-yard, 

 and this hole being continued a few inches into the rock 

 or the llone ben.;ath, a ilrong trenail, or oaken pin, was 

 driven through it, to pin it fait in its place : as liie dove- 

 tails did not of courfe fit perfecVy clofe into each other, but 

 left fpace for the mortar ; notches were cut in the edijes 

 of each llone to receive ftrong oak wedges, which lield 

 them firm until the mortar came to its folidit.y. As a further 

 precaution to defend the nuirtar, all the outward joints were 

 coated over with plafter of Paris, as a temporary expedient. 

 The woi-k went on r.ipidiy in tliis manner, and the (ecund 

 courfe was nearly fct in a few days ; but a ga'e fprang up, 

 which obliged them to quit the work, le?,viiig a few Hones 

 of the fecoiid courfe, which could not be fet, lowered down 

 into their places, and chained Hrongly to the rock, by lines 

 inferled into the holes made in each of the Hones, to lift 

 them by ; and one o^ the moll expafed was fecured, by 

 laying upon it, when in its dove-tail, a weight of lead of 

 five cwt. in form of a hemifpherc. A llorm came on, and 

 it was afterwards found, that this weight had been lifted 

 by the waves, fo th.it the Hone beneath it had efcaped and 

 was loll, as were four others, from which circumftance the 

 force of the fea on the rock may be imagined. New Hones 

 were immediately prepared, and the work renewed. In tl'.e 

 progrefs of the work, it conilantly happened, after all pre- 

 cautions, tliiit the cement was waftied away in particuiair 

 I places. 



