2. That every defensive preparation upon such a dam may be easily strengthened to such a degree as to become impregnable.

3. But that, because the defensive is so hemmed in, he must confine himself to the most passive resistance as respects each isolated point, and consequently must look for his safety entirely from passive resistance.

4. That in such a country it is not a system of a single defensive line, closing the country like a simple barrier, but that as in every direction the same obstacle to movement exists, and the same security for flanks may be found, new posts may incessantly be formed, and in this manner any portion of the first defensive line, if lost, may be replaced by a new piece. We may say that the number of combinations here, like those on a chessboard, are infinite.

5. But while this general condition of a country is only conceivable along with the supposition of a high degree of cultivation and a dense population, it follows of itself that the number of passages, and therefore the number of posts required or their defence, must be very great in comparison to other strategetic dispositions; from which again we have, as a consequence, that such a defensive line must not be long.

The principal line of defence in Holland is from Naarden on the Zuyder Zee (the greater part of the way behind the Vecht), to Gorcum on the Waal, that is properly to the Biesbosch, its extent being about eight miles. For the defence of this line a force of 25,000 to 30,000 was employed in 1672, and again in 1787. If we could reckon with certainty upon an invincible resistance, the results would certainly be very great, at least for the provinces of Holland lying behind that line.

In 1672 the line actually withstood very superior forces led by great generals, first Condé, and afterwards Luxembourg, who had under their command 40,000 to 50,000 men, and yet would not assault, preferring to wait for the winter, which did not prove severe enough. On the other hand, the resistance which was made on this first line in 1787 amounted to nothing, and even that which was made by a second line much shorter, between the Zuyder Zee and the lake of Haarlem, although somewhat more effective, was overcome by the Duke of Brunswick in one day, through a very skilful tactical disposition well adapted to the locality, and this although the Prussian force actually engaged in the attack was little, if at all, superior in numbers to the troops guarding the lines.

The different result in the two cases is to be attributed to the difference in the supreme command. In the year 1672 the Dutch were surprised by Louis XIV., while everything was on a peace establishment, in which, as is well known, there breathed very little military spirit as far as concerned land forces. For that reason the greater number of the fortresses were deficient in all articles of material and equipment, garrisoned only by weak bodies of hired troops, and defended by governors who were either native-born incapables, or treacherous foreigners. Thus all the Brandenburg fortresses on the Rhine, garrisoned by Dutch, as well as all their own places situated to the east of the line of defence above described, except Groningen, very soon fell into the hands of the French, and for the most part without any real defence. And in the conquest of this great number of places consisted the chief exertions of the French army, 150,000 strong, at that time.

But when, after the murder of the brothers De Witt, in August 1672, the Prince of Orange came to the head of affairs, bringing unity to the measures for national defence, there was still time to close the defensive line above-mentioned, and all the measures then adopted harmonised so well with each other that neither Condé nor Luxembourg, who commanded the French armies left in Holland after the departure of the two armies under Turenne and Louis in person, would venture to attempt anything against the separate posts.

In the year 1787 all was different. It was not the Republic of seven united provinces, but only the province of Holland which had to resist the invasion. The conquest of all the fortresses, which had been the principal object in 1672, was therefore not the question; the defence was confined at once to the line we have described. But the assailant this time, instead of 150,000 men, had only 25,000, and was no mighty sovereign of a great country adjoining Holland, but the subordinate general of a distant prince, himself by no means independent in many respects. The people in Holland, like those everywhere else at that time, were divided into two parties, but the republican spirit in Holland was decidedly predominant, and had at the same time attained even to a kind of enthusiastic excitement. Under these circumstances the resistance in the year 1787 ought to have ensured at least as great results as that of 1672. But there was one important difference, which is, that in the year 1787 unity of command was entirely wanting. What in 1672 had been left to the wise, skilful, and energetic guidance of the Prince of Orange, was entrusted to a so called Defence Commission in 1787, which although it included in its number men of energy, was not in a position to infuse into its work the requisite unity of measures, and to inspire others with that confidence which was wanted to prevent the whole instrument from proving imperfect and inefficient in use.

We have dwelt for a moment on this example, in order to give more distinctness to the conception of this defensive measure, and at the same time to show the difference in the effects produced, according as more or less unity and sequence prevail in the direction of the whole.