Blockade, however, implies not merely a sufficient number of cruisers to prevent the entry or departure of merchant ships. It further implies, because it requires, a strong supporting force sufficient to resist being driven off by an attack from within or from without the port; for it is an accepted tenet of international law that a blockade raised by force ceases to exist, and cannot be considered re-established until a new proclamation and reoccupancy of the ground in force. Hence it follows that, prior to such re-establishment, merchant vessels trying to enter or to depart cannot be captured in virtue of the previous proclamation. Consequent upon this requirement, therefore, the blockades on the north and on the south side, to be secure against this military accident, should each have been supported by a division of armored ships capable of meeting Cervera's division on fairly equal terms; for, considering the sea distance between Cienfuegos and Havana, one such division could not support both blockades. It has already been indicated why it was impossible so to sustain the Cienfuegos blockaders. The reason, in the last analysis, was our insufficient sea-coast fortification. The Flying Squadron was kept in Hampton Roads to calm the fears of the seaboard, and to check any enterprise there of Cervera, if intended or attempted. The other division of the armored fleet, however, was placed before Havana, where its presence not only strengthened adequately the blockading force proper, but assured also the safety of our naval base at Key West, both objects being attainable by the same squadron, on account of their nearness to each other.