Chap. VIII.

BRITAIN .

$83

steadying the stones of the solid, 8 large circular chains, two used at each vaulted floor, 221strong iron cramps in the walls of the rooms and lantern, and 5 others in the foundation.

The whole time occupiedbetween the first stroke uponthe rock and leaving the light-house complete was 3 years, 9weeks, and 3 days.

The stone employed waspartly obtained from the neigh-bouring coasts, and from the Isleof Portland.

For the lower part of thebuilding Smeaton contractedfor 240 tons of moorstone orgranite, which was consideredto be preferable in point ofduration, the price of whichwas 2 5s. per ton, roughed outaccording to the moulds, and4d. per foot superficial forworking the beds; this was theprice delivered into the yard,and did not comprise the ex-pense of carriage to the rock;the rest of the stone was broughtfrom the Isle of Portland.

The lantern, as originallycontrived by Smeaton, containeda chandelier 6 feet 4 inches indiameter, made for 16 candles ;and a smaller, 3 feet 4 inchesin diameter, for 8 ; they wereso disposed as to affect eachother as little as possible bytheir heat.

In the year 1807 the TrinityHouse had the building tho-roughly examined and sometrifling repairs performed, re-moved the chandeliers andintroduced in their place areflector frame, fitted up withArgand burners and parabolicreflectors, formed of copper,covered with highly polishedsilver.

The Granite usedfor this workwas obtained from the quarry,by splitting it with a numberof wedges, applied to holes ornotches, cut or pooled into thesurface, made at a distance ofabout 4 inches apart, or ac-cording to the size requiredor the strength of the stone.

These pool-holes weresunk withthe point of a pick, in the wayhard stones are usually quarried.

The harder the granite, themore exactly it may be made tosplit to the size required; inmany parts of Devonshire andCornwall , the moorstone orgranite is split into posts, 12or 14 feet in length, and ascantling of 8 or 9 inches square,and the sides perfectly even.

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Fig. 391 section or eddystonb lic.hthou