Again, the system of defence proved to be imperfect. Every part of the empire depended for prosperity--some parts depended for existence--on practically unrestricted traffic on the ocean. This, which might be assailed at many points and on lines often thousands of miles in length, could find little or no defence in immovable fortifications. It could not be held that the existence of these released the fleet from all duty but that of protecting our ocean commerce, because, if any enemy's navy was able to carry out an operation of such magnitude and difficulty as a serious attack on our home territory, it would assuredly be able to carry out the work of damaging our maritime trade. Power to do the latter has always belonged to the navy which was in a position to extend its activity persistently to the immediate neighbourhood of its opponent's coast-line. It is not to be supposed that there was no one to point this out. Several persons did so, but being mostly sailors they were not listened to. In actual practice the whole domain of imperial strategy was withdrawn from the intervention of the naval officer, as though it were something with which he could not have anything to do. Several great wars had been waged in Europe in the meantime, and all of them were land wars. Naval forces, if employed at all, were employed only just enough to bring out how insignificant their participation in them was. As was to have been expected, the habit of attaching importance to the naval element of imperial defence declined. The empire, nevertheless, continued to grow. Its territory was extended; its population, notably its population of European stock, increased, and its wealth and the subsequent operations of exchanging its productions for those of other countries were enormously expanded. At the same time the navy, to the strength and efficiency of which it had to look for security, declined absolutely, and still more relatively. Other navies were advancing: some had, as it were, come into existence. At last the true conditions were discerned, and the nation, almost with one voice, demanded that the naval defences of the empire should be put upon a proper footing.