The British force was divided into two attacks, called “right”[157] and “left,”[158] their contiguity being broken by a deep ravine through which passed the Woronzoff road. The right abutted on the heights overlooking the middle ravine, and the left leaned away to the position of the allies, but separated from it by the precipitous sides of the Picket House ravine, which debouched on the head of the inner harbour. No longer attached to divisions, the fourth, eighth, and tenth companies of sappers were appointed to the right, and the third and eleventh companies to the left. The united strength of the companies amounted to a force of about 386 non-commissioned officers and men, 32 of whom were sick and 21 at Balaklava. On the high road leading from Sebastopol, and near the windmill, was stationed the engineer depôt for the right attack; while that for the left occupied an area in rear of the third division, on a plateau adjacent to the artillery depôt. At both the parks, the carpenters, sawyers, and blacksmiths of the companies carried on the mechanical requirements of the operation unprotected from the weather, or at best in scanty sheds of the most primitive character. In order that the sappers might be easily distinguished in the trenches, they were ordered to wear a band of white tracing tape round the forage-cap. The strength of the brigades of sappers altogether depended upon the exigencies of the duty, and the numbers available for work. As a general rule, however, each brigade of sappers comprised a non-commissioned officer and eight privates; and each brigade of carpenters a non-commissioned officer and three privates. Whatever may have been the changes in the distribution of the men, there were seldom less at work, on the right, than three brigades of sappers and two of carpenters by day; and two of sappers and one of carpenters by night; while on the left, where a diminished force was employed, the arrangements only permitted for the daily routine two brigades of sappers and one of carpenters; and, for the night duty, one brigade of each. Usually, the brigade remained twelve hours in the trenches, being relieved at daybreak and soon after dusk; but this period of duty, on many occasions, was necessarily prolonged, when any pressure required particular works to be completed in haste. Some of the most reliable men were on duty in the front eight nights out of nine. Fatigue and sickness caused very inconvenient fluctuations in the numbers disposable for the operation; but when less vigour was demanded in the formation of the lines, the men were relieved from duty in the trenches for three or four days at a time—the interval being filled up with labours in the camp, and in the performance of a variety of services subsidiary to the siege.