CHAP. IV. SMEATON'S LIGHTHOUSE ON THE EDDYSTONE. 37 



order to insure the greatest possible accuracy in size 

 and fitting. Nearly four hundred and fifty tons of stone 

 were thus dressed by the time the weather was suffi- 

 ciently favourable for the commencement of the building. 

 At the same time he bestowed great pains upon experi- 

 ments, which he himself conducted, for the purpose of 

 determining the best kind of cement to be used in laying 

 the courses of the lighthouse, and eventually fixed upon 

 equal quantities of the lime called blue lias and that 

 called terra puzzolano, a sufficient supply of which he 

 was fortunate enough to procure from a merchant at 

 Plymouth, who had imported it on adventure, and was 

 willing to sell it cheap. It was also settled to use the 

 finest grout for the intervals between the upright or 

 side joints of the dovetailed part of the work. In the 

 early part of the spring he made several visits of inspec- 

 tion to the quarries where the rough stones were being 

 prepared, in order to satisfy himself as to the progress 

 made. On one of such occasions a severe storm of 

 thunder and lightning occurred at Lostwithiel, by which 

 the church spire was shattered ; and this turned his 

 attention to the best mode of protecting his lighthouse 

 against a similar accident. In the mean time he trans- 

 mitted an account of the storm and the effects of the 

 lightning on Lostwithiel Church to the Eoyal Society, 

 amongst whose papers it stands recorded. 1 Dr. Franklin 

 had shortly before published his mode of protecting 

 lofty buildings by means of conductors, and Mr. Smeaton 

 eventually determined, for the security of his lighthouse, 

 to adopt this plan. 



The building on the rock was fairly begun in the 



in which they were to be permanently 

 fixed. The engineer applied to the 

 Mayor of Plymouth for the use of 

 the Guildhall for the purpose, but 

 he was refused on the pretence that 

 the chalk-lines would spoil the floor. 

 He was also refused the use of the 

 Assembly-rooms for some similar rea- 



son. But at length, by taking down 

 a partition in the coopers' workshops, 

 he was eventually enabled to effect 

 his purpose without exposing himself 

 to further refusals from the local mag- 

 nates of Plymouth. 



1 * Philosophical Transactions,' vol. 

 50, p. 198. 



