The fortress of the future will probably be in the nature of an intrenched camp. The interior of the position will provide casemate accommodation for an army of considerable strength. Its defences will consist of a circle at intervals of about 2500 yards, of permanent redoubts which shall be invisible at moderate ranges for infantry and machine guns, the garrison of each redoubt to consist of a half battalion. Such a work was in 1886 constructed at Chatham in thirty-one working days, to hold a garrison of 200 men housed in casemates built in concrete, for less than £3000, and experiments proved that it would require a "prohibitory expenditure" of ammunition to cause it serious damage by artillery fire. The supporting defensive armament will consist of a powerful artillery rendered mobile by means of tram-roads, this defence supplemented by a field force carrying on outpost duties and manning field works guarding the intervals between the redoubts. Advanced defences and exterior obstacles of as formidable a character as possible will be the complement of what in effect will be an immensely elaborated Plevna, which, properly armed and fully organised, will "fulfil all the requirements of defence" while possessing important potentialities of offence. An illustration is pertinent of the pre-eminent utility of such fortified and strongly held positions, of whose characteristics the above is the merest outline. In the event of a future Franco-German War, the immensely expensive cordon of fortresses with which the French have lined their frontier, efficiently equipped, duly garrisoned and well commanded, will unquestionably present a serious obstacle to the invading armies. The Germans talk of _vive force_--shell heavily and then storm; the latter resort one for which they have in the past displayed no predilection. Whether by storm or interpenetration, they will probably break the cordon, but they cannot advance without masking all the principal fortresses. This will employ a considerable portion of their strength, and the invasion will proceed in less force, which will be an advantage to the defenders. But if instead of those multitudinous fortresses the French had constructed, say, three such intrenched-camp fortresses as have been sketched, each quartering 50,000 men, it would appear that they would have done better for themselves at far less cost. Each intrenched position containing a field army 50,000 strong would engross a beleaguering host of 100,000 men. The positions of the type outlined are claimed to be impregnable; they could contain supplies and munitions for at least a year, detaining around them for that period 300,000 of the enemy. No European power except Russia has soldiers enough to spare so long such a mass of troops standing fast, and simultaneously to prosecute the invasion of a first-rate power with approximately equal numbers. France at the cost of 150,000 men would be holding supine on her frontier double the