life. In 1887 he received the knighthood of the Annunziata, the highest
Italian decoration, and on the 8th of August 1889 died while a guest of
King Humbert in the royal palace of Capodimonte near Naples. Cairoli was
one of the most conspicuous representatives of that type of Italian public
men who, having conspired and fought for a generation in the cause of
national unity, were despite their valour little fitted for the responsible
parliamentary and official positions they subsequently attained; and who by
their ignorance of foreign affairs and of internal administration
unwittingly impeded the political development of their country.

CAISSON (from the Fr. _caisse_, the variant form "cassoon" being adapted
from the Ital. _casone_), a chest or case. When employed as a military
term, it denotes an ammunition wagon or chest; in architecture it is the
term used for a sunk panel or coffer in a ceiling, or in the soffit of an
arch or a vault.

In civil engineering, however, the word has attained a far wider
signification, and has been adopted in connexion with a considerable
variety of hydraulic works. A caisson in this sense implies a case or
enclosure of wood or iron, generally employed for keeping out water during
the execution of foundations and other works in water-bearing strata, at
the side of or under rivers, and also [v.04 p.0958] in the sea. There are
two distinct forms of this type of caisson:--(1) A caisson open at the top,
whose sides, when it is sunk in position, emerge above the water-level, and
which is either provided with a water-tight bottom or is carried down, by
being weighted at the top and having a cutting edge round the bottom, into
a water-tight stratum, aided frequently by excavation inside; (2) A
bottomless caisson, serving as a sort of diving-bell, in which men can work
when compressed air is introduced to keep out the water in proportion to
the depth below the water-level, which is gradually carried down to an
adequately firm foundation by excavating at the bottom of the caisson, and
building up a quay-wall or pier out of water on the top of its roof as it
descends. An example of a caisson with a water-tight bottom is furnished by
the quays erected alongside the Seine at Rouen, where open-timber caissons
were sunk on to bearing-piles down to a depth of 93/4 ft. below low-water,
the brick and concrete lower portions of the quay-wall being built inside
them out of water (see DOCK). At Bilbao, Zeebr