The interruption or destruction of the enemy’s commerce has always been one of the objects in naval warfare. British floating commerce offered a very large target, and the swift German cruisers, directed by wireless telegraphy and supplied by friendly neutrals, were at work on the lines followed by shipping, making it inevitable that there should at first be considerable losses to the Allies. Admiral Mahan thought that the British total losses in the long wars of the French Revolution and Empire did not exceed 2½ per cent. of the commerce of the Empire. The Royal Commission on the Supply of Food in Time of War expressed the opinion that 4 per cent. would have been a more accurate estimate. [Illustration: A DRIFTER AT SEA: LOOKING FOR SUBMARINES AND MINES] [Illustration: A DRIFTER LAYING ANTI-SUBMARINE NETS.] German cruisers, destructive as a few of them were, did not inflict losses amounting to anything like the figures of the old wars. In those contests of power, notwithstanding the depredations of commerce-destroying frigates, British oversea trade grew, while that of the enemy withered away. If the enemy captured ten British ships out of a thousand the loss might be considered serious, but if the British frigates captured ten out of the enemy’s hundred the injury inflicted was ten times more effective. Towards the end of the long war with France very few French traders were captured because scarcely any ventured to sea, while the French continued to capture English ships up to the very end of the war, ten years after their fleet had been destroyed at Trafalgar. The loss by capture and sinking was at the rate of 500 ships a year, and even in 1810, 619 English ships were lost.