Captain S. )^xo\vn\-s Description of the 
that gentleman for his exertions in promoting this desirable ob- 
ject and for his ability and judgment in the choice of the most 
suitable situation. 
The Magistrates of Edinburgh gave the best proof of their 
approbation of the plan, by their acquiescence in its erection on 
the place which Mr Crichton had pointed out, and by relinquish- 
ing their right of any toll or pontage. The Pier Company are 
also particularly indebted to Mr Scott, the proprietor of Trinity 
Bank, for the grant of a considerable piece of land for the site of 
the bridge, and for forming approaches, and erecting a convenient 
house for the accommodation of travellers. These material points 
being settled, I began to drive the piles in the month of March 
1821, but there was a succession of heavy gales which rendered 
the operation extremely difficult and tedious. It was not until 
the beginning of July, that the whole of the piles were driven, 
and completed for carrying the standards. 
The only improvement which I have attempted in the erec- 
tion of Trinity Pier, is that of using strong bolts over the points 
of suspension, where the stress is greatest, and diminishing them 
towards the centre, where it is least ; but not without such mecha- 
nical accuracy as to proportion every bolt to the strain which it 
has to bear in the curve. The extreme length of the pier is 700 
feet from high-water mark, 4 feet wide, and consists of three 
equal divisions of 209 feet, without any central support, and is 
10 feet above high-water. The pier-head is 60 feet wide by about 
SO long, supported by 46 piles driven about 8 feet into stiff blue 
clay. The heads of the piles are secured by beams at right 
angles, and by diagonal trusses and warping, which at the same 
time form a secure frame for the deck of 2 inch plank. The 
front of the pier faces the north-east, and is exposed to the 
v/hole range of the sea from the entrance of the Forth. It has 
also to support the drag of the bridge, and therefore it is 
strongly sustained and backed by diagonal shores, driven in op- 
posite directions. The intermediate piers are only subject to 
pressure from the weight of their respective divisions, and are 
greatly sheltered from the swell by the outer pier. Their area, 
therefore, is merely sufficient to form a secure framing for the 
cast-iron standard, over which the main suspending bars arc 
.^supported. 
