the superiority of Mr. Ferguson's system of fortification, meaning thereby the superiority of earthworks over works with deep ditches revêted with masonry; but this is not treating Mr. Ferguson fairly, for his method does not alone consist in the employment of earthworks. The only similarity between his method and the fortifications of Sebastopol is, that earthworks exist in both.

The system on which Sebastopol was defended was the system of an unlimited supply of provisions and men from without, and of all the munitions of war from within; the system of a garrison superior to the besieging force (for the garrison and the Russian army in the field were synonymous), and exposed to no one of the disadvantages of a besieged town except the flight of shot and shell. Sebastopol was defended by the spade and pickaxe; the workmen employed were 100,000 men. If the Allies could have invested the town, the gigantic works which alone delayed its capture never could have been constructed, and under the terrible vertical fire of the Allies a garrison of 30,000 men would have disappeared in two months.

Again, the Russian earthworks were so knocked about by our fire that our soldiers could mount them without the aid of scaling ladders in every direction; if those works had been provided with deep ditches and masonry revêtements, although we now know that our vertical fire must have reduced the place, it never would have been taken by assault. A dozen breaches made during the day would, by means of the unlimited supply of labour at the command of the defenders, have been entrenched during the night so as to become impregnable. Let any one read Napier's description of the great breach at Badajos and the assault upon it, and then consider what would

have been our chances of success in assaulting the breaches of a place whose supply of labour, materials, and defenders was practically unlimited.

The experience of the siege of Sebastopol has only tended to vindicate the correctness of those principles of fortification, which have received the sanction of all great engineers since the time of Vauban.

EXAMPLES TO CHAPTERS II. AND III.

Example 1.- Campaign of 1756 by Frederick the Great. (See Plate I.)—Frederick's plan of campaign was to take Dresden the capital of Saxony, and afterwards to invade Bohemia and take Prague, with the intention of wintering there with his army, if successful. At the outset of the campaign Austria was unprepared to repel an invasion of Bohemia, and the army which Frederick had opposed to him in Saxony amounted to only 18,000 men.

Frederick had two armies on foot; the one commanded by himself, of 64,000 men, destined to invade Saxony; the other under Marshal Schwerin, of 30,000, was at Nachod on the eastern frontier of Bohemia, and destined to co-operate with Frederick in the invasion of Bohemia.

Frederick invades Saxony, and takes Dresden 6th September. The Saxon army having evacuated that city retires to the entrenched camp of Pirna.

Meanwhile the Austrians assemble two armies, the largest under Marshal Braun at Kollin, destined to advance into Saxony to disengage the Saxon army (reduced to 14,000 men) blockaded in Pirna; the other under Piccolomini to oppose Schwerin.

Frederick, not thinking it safe to leave the Saxon army in his rear, blockades Pirna in the hope of reducing it by famine, and detaches 30,000 men under Marshal Keith to Aussig, to observe the Austrian army coming from Kollin.

Here it is to be remembered that the Prussian aggregate force was very superior to that of the Austrians.

Frederick's own army of 64,000 was very superior both in numbers and quality, to that of Braun. Schwerin's was likewise superior in number and quality to that of Piccolomini.

An examination of the map will show at once that Frederick was acting on two lines of operation at a great distance asunder, and separated by the Elbe.

The Austrians also employed two lines, but it is evident that these were interior to those of Frederick, since the troops upon them were clearly more easily unitable. The two Austrian armies were back to back, and could join by a direct march in a straight line; while Frederick and Schwerin, to unite, must either first defeat the forces respectively opposed to them, or must make a circuitous march behind the frontier of Bohemia.

Marshal Braun advances from Kollin to Budyn on his march to relieve Pirna, 23rd Sept. Frederick takes command of the army of observation and marches to meet Braun. The two forces encounter

at Lowositz where Frederick is victorious, 30th September. On the 14th of October the Saxon army surrenders at Pirna; but it is then too late to undertake any fresh operation, and the Prussians retire from Bohemia to winter in their own territories.

Remarks. In this campaign Frederick violated Principle 3 by adopting exterior lines of operation, and neglected Principle 1, because, although his forces were very superior to those of his opponent, he was notwithstanding inferior at the decisive point. His strength was frittered away; he had 34,000 blockading the Saxons in their camp at Pirna; 30,000 under Schwerin paralysed by an Austrian force inferior both in numbers and quality on the eastern frontier of Bohemia; while at the decisive point he had only 30,000 men to oppose a superior Austrian army. Schwerin's force should have been united to Frederick's; it was a positive evil to the king to hinder the junction of Piccolomini with Braun, when the price paid for it deprived him of the services of Schwerin's army. Again, the entrenched camp at Pirna was defended by only 14,000 Saxons, and although very strong, it was far too extensive to be effectually defended by such a force, its circuit amounting to about twenty-five miles. Had Frederick assaulted this camp with his whole force, 64,000, he would certainly have taken it, in which case he would have had 64,000 men minus his