nts in fact which make for defence in case
of invasion over an uncommanded sea also go to facilitate timely contact
with an expedition seeking to operate by evasion. Nor must it be forgotten,
since the problem is a combined one, that the corresponding developments
ashore tell with little less force in favour of the defending army. Such
appear to be the broad principles which govern an enemy's attempts to act
with combined expeditions in our own waters, where by hypothesis we are in
sufficient naval strength to deny him permanent local command. We may now
turn to the larger and more complex question of the conduct of such
expeditions where the naval conditions are reversed.

By the conduct, be it remembered, we mean not only their defence but also
their support, and for this reason the starting-point of our inquiry is to
be found, as above indicated, in the contrast of combined expeditions with
convoys. A convoy consists of two elements--a fleet of merchantmen and an
escort. But a combined expedition does not consist simply of an army and a
squadron. It is an organism at once more complex and more homogeneous. Its
constitution is fourfold. There is, firstly, the army; secondly, the
transports and landing flotilla--that is, the flotilla of flat-boats and
steamboats for towing them, all of which may be carried in the transports
or accompany them; thirdly, the "Squadron in charge of transports," as it
came to be called, which includes the escort proper and the supporting
flotilla of lighter craft for inshore work; and lastly, the "Covering
squadron."

Such at least is a combined expedition in logical analysis. But so
essentially is it a single organism, that in practice these various
elements can seldom be kept sharply distinct. They may be interwoven in the
most intricate manner. Indeed to a greater or less extent each will always
have to discharge some of the functions of the others. Thus the covering
squadron may not only be indistinguishable from the escort and support, but
it will often provide the greater part of the landing flotilla and even a
portion of the landing force. Similarly, the escort may also serve as
transport, and provide in part not only the supporting force, but also the
landing flotilla. The fourfold constitution is therefore in a great measure
theoretical. Still its use is not merely that it serves to define the
varied functions which the fleet will have to discharge. As we proceed it
will be seen to