Transcript – Unlocking the Archives

Document 35, P 14

thereto in the same method with lesser Dams to drain out the water (he having)
found that within that Compass the Bed of Gravel appeared equally hard and
compact) the method that naturally offered itself was to found the rest of the
Piers by Caisson a method the most easy and ready, and atended with the
least cost of any so that having before abundantly experienced that good Quarry
Rubble would resist the action of a current to a greater degree than any [kind?]
of Gravel it appeared that the Pillars so sunk being defended from Accidental
Floods till they could be surrounded by a slope of Rubbles (which the depth of
the water naturally admitted in this place) hence would arise every degree
of Security that the nanture of the Subject would admit of.
He concluded therefore to build a Bridge of nine Arches instead of seven that
it might have more legs to stand upon in Consequence of the natural weakness
of the Stratum and by way of Security to the Piers before they could be properly
and sufficiently surrounded by the proposed Slope of Rubble as well as after
in case of any derangement of the Rubble defence a Girdle of Stones in Blocks
of a Ton Weight and upwards was proposed to be let down and surround the
Base of each Pier to be fitted to each other and to the Pier they surrounded and
to be cramped together.
Upon this Idea of Construction Mr Smeaton formed his Original Estimate
and which from the simple mode of it could be executed for a very moderate
Sum of Money in proportion to the largeness of the River, and Extent of the Work
and which in Consequence was bargained for by Mr Errington and the Work
proceeded with accordingly.
The North Land breast and the adjoining Pier were successfully built upon
Piles incased as proposed and the Gravel there being very sufficiently compact
(so as to afford only a moderate quantity of water) Mr Smeaton determined to
try to go on as far as he could upon that principle and therefore ordered the
Second Pier from the North Abbutment to be tried with a Coffer dam to encavate
and found like the first, but when the Pitt was sunk but two feet under the
Levell of the Water outside, and not much more than half as much under
the natural Bed of the River the water boiled up between the Intersteces
the Gravel Stones bringing up Sand along with that it required
14 forty

Page image available

Note: Mr Smeaton's Memorial, p 14

Abbreviations are underlined like this Wm. and the expansion may be seen by moving the cursor over it.

An entry outlined like this has a note which may be seen by hovering over it.

Transcribed by CTW and KS