variety of fantastic changes which it is in the power of each to
assume." The Menai Straits are about twelve miles long, through which,
imprisoned between the precipitous shores, the waters of the Irish Sea
and St. George's Channel are not only everlastingly vibrating, backwards
and forwards, but at the same time and from the same causes, are
progressively rising and falling 20 to 25 feet, with each successive
tide, which, varying its period of high water, every day forms
altogether an endless succession of aqueous changes.




THE TUBES.


The tubes forming the viaducts, rest upon two abutments and three piers,
called respectively the Anglesea abutment and pier, the Carnarvon
abutment and pier, and the Britannia or central pier, built upon the
Britannia rock in the middle of the straits, which gives name to the
bridge. The Anglesea abutment is 143 feet 6 inches high, 55 feet wide,
and 175 feet long to the end of the wings, which terminate in pedestals,
supporting colossal lions on either side, 25 feet 6 inches in length, 12
feet 6 inches high, and 8 feet broad, carved out of a single block of
Anglesea marble. The space between the Anglesea abutment and pier is 230
feet. This pier is 196 feet high, 55 feet wide, and 32 feet long. The
Carnarvon abutment and pier are of the same dimensions as those above
described, on the opposite shore. The Britannia pier is 240 feet high,
55 feet wide, and 45 feet long. This pier is 460 feet clear of each of
the two side piers. The bottom of the tubes are 124 feet above low water
mark, so that large ships can pass under them, under full sail.