This sounds well in theory, but in practise the difficulties will be well-nigh insuperable. Those who know the coast will remember the miles and miles of shallows—the so-called _Wattenmeer_ so difficult to navigate. In time of war all lighthouses and buoys are removed and, if they approach the shore, the English ships will inevitably run aground, while the German torpedo-boats and submarines will be in their very element. Floating mines, too, will get in their deadly work, as will also the strings of fixed mines which are ignited not by percussion but by means of an electric current controlled from the shore. The German fleet can retire well up the great streams and menace the enemy there; while it must not be forgotten that the great cannon of the coast defenses can shoot fifteen kilometers (nine and three-eighths miles) or more. Finally the islands in the neighborhood, notably Borkum and Wangerood, are fortified, and last but not least, there is Helgoland far out in the sea. A whole fleet could not take this Gibraltar of the North. The rocky walls are very hard; indeed, with true German thoroughness, they have been tested to see if they would successfully withstand bombardment. Under their shelter a harbor for torpedo-boats and submarines has been built at a cost of thirty million marks. From here they can issue forth and here, protected from afar by the great guns, they can take refuge and form new projects. Troetsch considers it more than likely that England will proceed to a blockade, but a blockade not in the narrow but in a broader sense. One objection to the narrower blockade would be that her naval bases, necessary for repairs, fuel and ammunition, would be very far away. But this can be obviated if the blockading line begin somewhere between Dover and Calais, extend along the east coast of Scotland, with bases at Rosyth and Scapa Flow, and end near the southernmost point of Norway, Cape Lindesnaes. This would shut every exit from the North Sea to the Atlantic and at the same time encircle all the exits from the Baltic: the Skager Rak and Cattegat and the Kaiser Wilhelm Canal. Here England could carry on what is known as an “observation blockade,” biding her time to fall upon the enemy’s fleet. The great disadvantage is that the blockading line will have to be so very long. The surface of the North Sea is about equal to that of the whole German Empire, and such a line as we have traced would extend for two hundred fifty or three hundred miles. It is a question if even England’s enormous fleet can spare the requisite number of ships. Such a blockading fleet consists not only of a long chain of vessels close together but also of a supporting fleet and, behind that, of the real battle squadrons. The whole force must be nearly double that of the enemy, as it operates on a much broader line. The foggy stormy weather that is apt to prevail in the North Sea will also render the blockade less efficient.