given directions that all the ordnance should be placed on common or ground platforms, the use of the traversing platforms was discontinued. It had previously been observed that no advantage or superior accuracy of fire attended raising the guns.

His Grace also ordered that the rubbish should be cleared from the breach; and it was found that the wall was about 5 feet in perpendicular height in front, with a rounding of rubbish of about 2 or 3 feet at top, and about 8 or 9 feet in height towards the rear (fig. 5).

Fig. 5.-Front View of the Wall when the Rubbish was cleared away from the BREACH, after the second day's fire.

On the 11th of August the batteries recommenced their fire from eight 68-pounder carronades, at 500 yards, and six 10-inch howitzers, at 400 yards; when 85 rounds from each howitzer, and 100 rounds from each carronade, were fired in three hours and a half, by which time the wall and buttresses were one mass of ruin (see figs. 6 and 7).

Fig. 7.-Side View of the Wall after the third day's fire.

The charge of the shells had been so much reduced, to avoid splinters reaching the batteries, that a considerable number did not burst.

From careful observation, it appeared that about one-fourth of the shells and onefifth of the shot struck the wall.

The increased rapidity of fire is remarkable, that of the third day being nearly double that of the first, although the reduction in the height of the wall, from 21 to 5 feet, rendered the operation obviously more difficult. A sketch of the counterguard (fig. 8) shows the effect of the shells on its superior slope.

Fig. 8.—General View of the Counterguard in front of the Wall after the last day's fire.

W. D.

FOUGASS.*

COMMON FOUGASSES.

Fougasses Ordinaires.-These are small mines made by simply placing a box of powder at the bottom of a pit excavated for the purpose, from 3 to 4 yards deep. They are usually fired by means of an auget led up the side of the pit, and then parallel to the surface of the ground, at a depth of from 2 to 3 feet.

The bottom of the pit should be made firm; the box containing the powder and the auget well pitched over, to keep out the damp; and in filling up the pit again, care should be taken that the earth is well rammed, and the ground around turned up for some distance, so that nothing may indicate the position of the fougass.

SHELL FOUGASSES.

Fougasses à Bombes.-These are formed by burying shells which are connected together so as to explode simultaneously, either in the place where they have been lodged, or as they come to the surface of the ground. The shells are placed in the upper part of a box, which is divided horizontally by a partition with holes in it, to allow the fuzes of the shells to project down through them.

In the lower part of the box sufficient powder may be placed to project the shells to the surface of the ground; or in case it is intended that they should explode where they are lodged, the powder hose may be connected directly with them. These are principally used for the defence of the glacis, and are represented in figs. 1, 2, and 3, in the Plate.

Single shells may also be used in this case the

:

Fougasses Pierriers.—An excavation, in the form of a frustum of a cone or pyramid, corresponding nearly with the form of the entonnoir of the intended fougass, is made; and a box of powder, to project the stones or other projectiles with which the excavation is to be filled, is placed under a 2 or 3-inch board at the bottom of it. The axis of the excavation should be inclined to the horizon at an angle of about 40°, and the sides inclined to the axis at an angle of 24°. Care should be taken that there is sufficient weight over the fougass to make the line of least resistance correspond with the axis.

As the effect of these mines is nearly the same whether the conical form is adopted or that of the frustum of a pyramid, and as this latter offers great advantage from the simplicity of its form and the greater rapidity of execution, it has not been

* By Lieutenant-Colonel James, R.E., F.R.S.

thought necessary to give directions for the construction of the ellipses of the former.

Figs. 7 and 4 represent the plan and section of a fougass, which, with a charge of 60lbs. of powder, will throw from 3 to 4 cubic yards of bricks or stones from 40 to 50 yards, spreading over a nearly equal breadth.

In no case should more ground be broken than is absolutely necessary. If it is firm, an excavation may be made at once, of the form indicated in fig. 5; but if the ground is bad, the back should be revetted with sods, as in fig. 8. The auget is placed in a trench of about 1 foot wide by 2 feet deep.

Figs. 5 and 6 represent the plan and section of a fougass, in which the back, sides, and bottom are made of plank, of the dimensions given. In bad ground, this is a good plan; indeed it is advisable to use wood for the support of the back wherever there is under-cutting.

This plan was tried experimentally at Athlone, in 1843. It is very readily executed, and produces a very good effect.

Figs. 8 and 10 represent the method which is used when it is not wished to charge the fougass till just before it is intended to fire it. In other cases the powder-box is slipped down a sort of shoot, which is immediately filled with sand-bags; and the pit in rear of it, as well as the trench for the auget, filled in with earth.

Fig. 9 represents a method by which a more rasante fire may be obtained, and which might be employed for the purpose of flanking ditches. In this case the axis is inclined about 20° to the horizon; the sides are inclined to each other at an angle of 45°. A revetment of sods is represented, for the purpose of confining the charge to the direction of the axis.

FRAISE.-Fraises are palisades laid horizontally, or nearly so, and they are fixed together in the same way: they have been usually placed on the bern of works, and may be considered the smallest obstacle for defensive purposes; they are, besides, expensive, and difficult of execution, and are therefore rarely applicable to fieldworks, and can only be fixed in permanent fortification advantageously, as explained in the diagram.

It has been found by experience,* that the fraise, in escalading works, serves as a footing rather than an obstacle, when placed on the berm.

When works are not revetted, and the exterior slope, as above, is at an angle of about 45°, and accessible, the fraise may be applied if flanked by a caponnière. (See also the Article 'Caponnière.') G. G.L.

FURNACE, SHOT †-(See 'SHOT FURNACE.')-The furnace at present in

* See Jones's Sieges,' vol. i. page 175, third edition, and fig. 12 to Article Escalade.'

The results obtained in actual practice are far below those given in the experiment, great difficulty being experienced in attaining anything like a white heat. Improvements have been suggested, but no substitute is yet adopted.-ED.