36 Account of the Erection of the Bell Rock Lighthouse. 
able, as the result of the ample experience, both practical and 
scientific, of Mr Stevenson, on the subject of marine buildings. 
In the preceding account, we have noticed some points in 
which the Edystone and the Bell Rock Lighthouses closely re- 
semble each other, and also some things in which they mate- 
rially differ. As we have been at some pains in tracing these, 
it may not be uninteresting to our readers to have them brought 
into a condensed view. 
At flood-tide, the top of the Edy stone rock is barely covered 
by the rise of the water, while the site of the Bell Rock Light- 
house is nearly on a level with low- water mark. Our Scottish 
fabric contains more than double the cubical contents of the 
masonry of the Edystone, the first entire course of -which mea- 
sures only 26 feet in diameter, while that of the Bell Rock ex- 
tends to 42 feet. This disparity of circumstances and dimen- 
sions necessarily rendered a different system of landing mate- 
rials upon the Bell Rock necessary, and the use of an apparatus 
for building, which, in many respects, was entirely new. We al- 
lude to the balance-crane and moveable beam-crane employed 
in place of the sheer-poles used by Mr Smeaton. It is, how- 
ever, mentioned by Mr Stevenson, with proper feelings of respect 
for the high merits of Mr Smeaton, that the Edystone Rock 
being of no greater extent than was necessary for the foundation 
of the building, the difficulties of the work were thereby increased 
to such a degree, that he is induced to conclude that the lower 
courses of the Bell Rock were, perhaps, upon the whole, not 
attended with greater hazard and difficulty than those of the 
Edystone. The larger dimensions of the Bell Rock, gave great- 
er facilities for the establishment of a more efficient working ap- 
paratus. The introduction of praam-boats, and a landing-mas- 
ter’s crew, for bringing the materials to the hands of the build- 
ers ; and the general application of machinery, varying in its 
construction and use, according to the position and circumstances 
of the work, will perhaps be the means of enabling the prac- 
tical engineer, at some future period, to extend his operations 
to far more difficult situations than have hitherto been contem- 
plated. — The same principle of dovetailing and connecting the 
stones of the lower courses, have been observed in both build- 
