It was deemed indispensable that a map should be provided of the country for several miles round the encampment, to guide the Generals in the choice of positions, manœuvres, marches, &c. The district had been surveyed sixty years before, in common with the general survey of the south of England, and was drawn on a scale of two inches to a mile. The better to meet the present requirement, the plans were enlarged and drawn to a scale of four inches to a mile. All the improvements which had arisen within the last half century were also supplied, and the original work corrected where necessary. This was done by taking magnetic bearings with a prismatic compass and pacing the ground. The distance examined and corrected, included an area of about 220 square miles, the cardinal angles of which were Chertsey, Wokingham, Farnham, and Guildford. All was carried out and completed between the 1st May and 14th June. The principal part of the hills were sketched by Lieutenant Stotherd, assisted by four non-commissioned officers of the corps, who, although heretofore wholly employed in the operations of a civil survey, were, without any previous practice in the art, made to turn their talents to account in military sketching. The survey—comprised on four large sheets—was compiled, lithographed, and coloured under the direction of Captain W. D. Gosset, R.E. Corporal Sinnett drew the 12-inch plan of the encampment furnished for the use of Colonel Vicars. A special survey of the ground at Aldershot Heath was also made and plotted on a scale of six inches to a mile, by sergeant Spencer and corporal Macdonald. The soldiers most conspicuous for their usefulness in the Chobham survey were— Sergeant Benjamin Keen Spencer; for surveying, levelling, and hill sketching. Corporal William Jenkins; trigonometrical observations, levelling, and traversing. Second-corporal James Macdonald; traversing and surveying. Lance-corporals John Erskine Daveran and Valentine Sinnett; hill sketching, surveying, &c. Marking out the encampment was done by the sappers under Colonel Torrens, assistant quartermaster-general, by driving pickets into the ground in the places selected to mark the salient points of the boundaries, to be occupied by the several regiments. The springs and watercourses were sought for and collected into small reservoirs or basins, at sites as convenient for access as practicable. In some places small trenches were excavated, to afford easy channels for conveying the water to the terraces. These tanks were for domestic uses. Attached to them were larger ones for washing purposes, which were filled by the surplus water from the drinking reservoirs through the agency of small troughs, fixed near the top of the partitional embankments.