The _Invincible_ was sent to the Tyne to change some of her 12-inch guns, which had become worn during the Falkland Island engagement. On April 10th Rear-Admiral Tottenham succeeded Rear-Admiral Waymouth in command of the 7th Cruiser Squadron, the latter officer’s health having unfortunately broken down. On April 7th the patrol areas of the 10th Cruiser Squadron were rearranged somewhat in view of the lengthening of the days: Patrol Area A was north of the Faroes, the centre line being occasionally shifted. Patrol Area C had as its centre a line from Cape Sydero in the Faroe Islands to Lat. 58.30 N., Long. 8.0 W. Patrol Area E was north of Iceland. Patrol Area F was south of Iceland. Patrol Area G had as its centre the meridian of 3° E. Long. between Lat. 62 N. and 63½ N. A cruiser was sent to strengthen the patrol in this area. During the month the average number of vessels intercepted weekly by the ships of the 10th Cruiser Squadron was 68, of which an average number of 23 was sent in weekly for examination. Enemy submarines were very active in April, and destroyers were sent out frequently from the Fleet bases to endeavour to destroy craft reported in the vicinity--particularly in the neighbourhood of the Fair Island Channel--but no success was achieved, except in the case of the _Ariel_ and U 12. The look-out and navigational arrangements for the Pentland Firth were improved during April by the establishment of telephonic communications between Scapa and the Island of Swona. Arrangements were also gradually perfected for obtaining the exhibition of all navigational lights and fog signals in the Pentland Firth on demand by our ships at all times. The weather at Scapa during April was bad. Gales were experienced on the 4th, 5th, 6th, 7th, 9th and 10th. There was a great deal of mist and fog during the latter part of the month as well as a moderate amount of snow. The enemy laid a large mine-field in the middle of the southern portion of the North Sea during April, thus pursuing the policy which it was expected he would adopt, regardless of the interests of neutrals. Fortunately, information as to its existence was obtained in time to prevent any of our ships from falling victims to the mines. But the mine-field was undoubtedly well placed strategically so as to interfere with the freedom of movement of our Fleet in southern waters if it were endeavouring to bring the High Sea Fleet to action, since it necessitated our ships making a wide detour to the eastward or westward to reach the waters to the southward of the mine-field; it was doubtless laid with this object in view. In May the Grand Fleet flotillas were much occupied in endeavouring to locate and destroy enemy submarines, and the movements of the heavy ships were curtailed during the month owing to the absence of destroyers for the purpose of acting as a submarine screen.