At Salamanca all the uncovered masonry wall, battered by four 18- pounders, at a distance of 300 yards, was beaten down in four hours. Two 18-pounders and one 24-pounder howitzer destroyed, at about 400 yards, another wall, three feet six inches thick, in half a day, notwithstanding sever loss from heavy firing of the enemy's cannon and musketry. Four 24-pounder howitzers failed to breach an oblique wall distant 450 yards, the firing being too inaccurate. The same battery with four 18-pounder guns afterward breached this oblique wall in six hours.

At Saint Sebastian, which is on a peninsula, the northern line of works, having he sea in front of the, is built without any cover, and thus is quite exposed to a range of hills opposite, at the distance of 600 or 700 yards. Twenty 24-pounders were put in battery on the 20th of July on these hills, to breach sea-wall. On the 23rd of July the breach was about 100 feet in length and was considered practicable. It was assaulted and the assault failed. On the 26th of August, more artillery having in the meantime been procured, batteries of thirteen guns opened, at 700 yards, against the right half bastion of a hornwork to the left, and twenty-one 24-pounders, in addition to the first twenty on the hills, battered the sea-wall, to extend the breach already formed. The town was carried on the 31st of August.

These instances show that it was practicable fifty years ago to breach masonry at 600 to 800 yards" distance with guns of 18 to 24 pounder caliber and of inferior quality. Accordingly, in the construction of scarps or masonry subject to be battered, the rule was adopted by the French that all masonry liable to be seen by land batteries at a distance of about thee-quarters of a mile should be covered by earth. In the case of our sea-coast forts subject to the fire of vessels no attempt has been made to cover the channel faces, because a wooden vessel attempting to breach them would be destroyed before she could inflict any serious damage upon the masonry. If an enemy manifest that before his preparations, except for a mere coup de main, were complete and his breaching guns in battery (operations requiring a great deal of time at any rate-in the case of Fort Pulaski many weeks, if not several months), he would be overwhelmed by a succoring force. The resolution does not contemplate any substitute for fortifications, but changes, if necessary, in their construction and materials.

No material can be devised affording so much strength of resistance, so indestructible by time and the elements, and so cheap as masonry.

The existing scarp-walls of our casemated batteries can readily be covered with iron plates, as certain thin portions of them have already been, whenever it becomes evident that they are not sufficient without such armor to resist armored vessels. The cost will be less than that of iron structures of any kind, but the result will be a solid mass several times more capable of resistance than the same money's worth of iron alone, or of iron and wood combined. This economy is true of any building placed on shore. It is far more true in comparison with any defense of a floating character.

The Monitor, for instance, cost about $285,000, and is armed with two 11-inch guns.

A 15-inch gun, throwing a solid round shot of 500 pounds, win cost, mounted, about $7,500. It can be covered most thoroughly, including iron plates, if necessary, for $12,500 more. Fourteen such guns, at least, can be mounted in a fort for the cost of the Monitor. It is