Even when coolly examining the direction of their trenches, after the close of the siege, it was very rare that a faulty direction could be detected; they always afforded excellent cover, and were well defiladed; in some cases the excavation of the double direct sap was carried to the depth of six and a half feet in the solid rock! The execution of many of the saps and batteries was worthy of a school of practice.

In the parallels, bombproofs were provided as temporary hospitals, offices for the generals on duty, etc.
They did not use the sapper armor.

The use of the sap-roller was often attempted, but it could be employed only during the latter part of the attack upon the Malakoff, when the fire of the Russian artillery was nearly extinguished by the mortars; before that, as soon as a sap-roller was placed in position--some thirty guns would be brought to bear upon it, the result being its immediate destruction.

It may justly be said of the French approaches, that they admirably carried into practice their system of sapping.

The technical skill and patient courage evinced by their officers and men in pushing forward such excellent approaches, under a most deadly fire, is worthy of all commendation, and is such as might have been expected from the antecedents of their corps of engineers." "With regard to the English, the case was different; it seemed as if they systematically abandoned the excellent system taught and perfected with so much care at Chatham.