It was imperative now for the British to finish off their capture of the German second position and to prepare for a German attack which might develop at any moment. From east of Pozieres to Delville Wood the enemy had lost their second line and were forced to construct a switch line to establish a connection between the third position and an uncaptured point, such as Pozieres, in his second position. There was stubborn fighting among the orchards of Longueval and the outskirts of Delville, where the British made little headway, but registered some gains. All their hopes were centered at this time on their chief objectives, Guillemont and Pozieres. The latter was especially important, for it formed a part of the plateau of Thiepval. If the British succeeded in gaining the crest of the ridge all the country to the east would come under direct observation. The most important points on the watershed were Mouquet Farm, between Thiepval and Pozieres, the Windmill east of the last place, High Wood, and the high ground that lay directly east of Longueval. It was important that the British should capture Guillemont in order to align the next advance with the French forces. This task presented many difficulties, for the advance from Trones Wood must be made over a bare and shelterless country that was under the Germans' direct observation from Leuze Wood. There was also a strongly fortified quarry on its western edge and a ravine to the south of it between Maltzhorn and Falfemont Farms, while Angle Wood in the center was a German stronghold. The difficulties of the British position were summarized by Sir Douglas Haig: "The line of demarkation agreed upon by the French commander and myself ran from Maltzhorn Farm due eastward to the Combles Valley, and then northeastward up the valley to a point midway between Sailly-Saillisel and Morval. These two villages had been fixed upon as the objective respectively of the French left and my right. In order to advance in cooperation with my right and eventually to reach Sailly-Saillisel, our Allies had still to fight their way up that portion of the main ridge which lies between Combles Valley on the west and the river Tortille on the east. To do so they had in the first place to capture the strongly fortified villages of Maurepas, Le Forest, Rancourt, and Fregicourt, besides many woods and strong systems of trenches. As the high ground on each side of the Combles Valley commands the slopes of the ridge on the opposite side, it was essential that the advance of the two armies should be simultaneous and made in the closest cooperation." The British made an attack on Guillemont from Trones Wood on July 19, 1916. It was a rainy, foggy day, that hampered military operations, and they failed to advance.