Tomlinson, Charles (1808-1897) Cyclopædia of useful arts, mechanical and chemical, manufactures,
mining, and engineering.
London, New York, G. Virtue & co., 1854.
After the tubes for the Britannia Bridge were completed,
they were floated into position between the towers on pontoons. The towers
had vertical channels built into them to accommodate the ends of the
tubes. The wood engravings in this encyclopedia article show how the tubes
were floated and placed in position. The top illustration is a scenic view
of a tube floating on eight pontoons to its position next to the tower.
The bottom illustration shows the main Britannia tower, with one set of
tubes already raised and the masonry filled in, and a third tube about
half-way up the tower.
