To keep communications open it is not necessary to secure every friendly ship traversing the line against attacks by the enemy. All that is necessary is to restrict the enemy's activity so far that he can inflict only such a moderate percentage of loss on the friendly vessels that, as a whole, they will not cease to run. Keeping communications open will not secure a friendly place against every form of attack. It will, however, secure a place against attacks with large forces sustained for a considerable length of time. If he can make attacks of this latter kind, it is clear that the enemy controls the communications and that we have failed to keep them open. If communications are open for the passage of vessels of the friendly mercantile marine, it follows that the relatively much smaller number of supply-vessels can traverse the line. As regards supply-vessels, a percentage of loss caused by the enemy must be allowed for. If we put this at 10 per cent.--which, taken absolutely, is probably sufficient--it means that _on_the_ _average_ out of ten supply-vessels sent we expect nine to reach their destination. We cannot, however, arrange that an equal loss will fall on every group of ten vessels. Two such groups may arrive intact, whilst a third may lose three vessels. Yet the 10 per cent. average would be maintained. This condition has to be allowed for. Investigations some years ago led to the conclusion that it would be prudent to send five carriers for every four wanted. The word 'group' has been used above only in a descriptive sense. Supply-carriers will often be safer if they proceed to their destination separately. This, however, depends on circumstances. INDEX Adventure, voyages of Agincourt, battle of Alcester, Lord Alexander the Great Alexandria, bombardment of American War of Independence; Sir Henry Maine on ---- War of Secession; raids in ---- War with Spain Ammunition, supply of; alleged shortage at the defeat of the Armada Army co-operation Athenian Navy; at the battle of Syracuse Australian Fleet, localisation of Austro-Prussian War Baehr, C. F Balaclava, capture of Bantry Bay, French invasion of Battleships, merits of; coal consumption of Beer, for the Navy Benedek, General Blockades Bounty for recruits Brassey, Lord Bright, Rev. J. F. Brougham, Lord Brunswick-Oels, Duke of Burchett, quoted Burleigh, Lord Byng, Admiral (_see_under_ Torrington, Earl of).