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and experienced soldiers. Under the above heads, and not including the constabulary force, which under certain circumstances would increase the defensive strength, we have, in round numbers, the following force in Great Britain and Ireland.

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The number of men voted under the Ordnance Estimates is, in round numbers, 15,000 artillery and 2,000 sappers and miners. Of these, 10,000 artillery, including 1,200 horse artillery and 660 sappers, of whom 400 are employed on the trigonometrical survey, are in the United Kingdom, making a grand total of:

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The Ordnance estimates show an increase of above half a million over last year, a large proportion of which is due to works of defence in progress or to be erected. The charge is 246,6277. for works to be executed, of which 201,5767. at home, and 33,9107. abroad, together, 235,4867., are for fortifications alone, not including the necessary barracks and store-houses in the new works.

The former of these sums is allotted, in various proportions, to the erection and improvement of works at the mouths of the Thames and Medway, at Dover, on the Sussex coast, at Portsmouth and Gosport, Portland Harbour, Guernsey and Alderney, Devonport, Milford and Liverpool; the harbour defence of which last important place has been resolved on since the year 1839, money has been voted for the purpose in 1846-7, and 1852-3; but most unaccountably, little or no progress has been made towards its completion up to this time.

No argument is needed to prove the necessity of rendering all the above places capable of defence; but, relying as England must mainly do, on her fleet for successful resistance to an attempt at foreign invasion; and giving due credit to the report, that when the difference arose between this country and France respecting Tahiti, King Louis Philippe had determined to make a sudden attack on Portsmouth, the success of which his officers did confidently anticipate, it will not be amiss to consider briefly the present condition of that, our greatest naval

arsenal, the destruction of which would cripple our fleet to an almost incalculable extent, and whose position, but eight hours' steaming from Cherbourg, would render it the most probable at which to aim a sudden blow.

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Mr. Fergusson, a gentleman known as the author of An Essay on a proposed New System of Fortification,' has, in the work whose title stands at the head of this Article, taken a very able view of the condition of Portsmouth, as regards its defences, both by sea and land; and has suggested a scheme of defensive works on his new system.

Our military readers, and probably many non-professional ones, will remember to have seen in the Gallery of the Great Exhibition in Hyde Park, a formidable looking model of a fortress, circular in form, with tier rising above tier of ramparts bristling with cannon. This was the embodiment, on a small scale, of the theory of fortification intended by its author to supersede those systems hitherto in use; and they who amongst the multitude of objects presented to them, overlooked this one, and yet feel a curiosity to behold it, will find the model at the United Service Institution in Scotland Yard.

A civilian, although he has from boyhood made fortification 'his favourite pursuit,' may not at first sight appear to be the fittest person to originate a system of fortification that should place the besieged on a footing of equality with the besieger, which it has hitherto baffled the most scientific military engineers to effect; nor would he be thought likely to receive a very cordial reception from them, when he ventured to trespass in their peculiar province. It is therefore no slight evidence of the merit of Fergusson's system, and of the liberality of our engineers, that this system has attained, during the summer, a very full and fair discussion on its merits, in the theatre of the United Service Institution, when many able officers spoke on both sides, and we believe the balance of argument was in favour of Mr. Fergusson.

Lieut. Colonel Adams, Professor of Fortification at Sandhurst College, had in the previous summer delivered a lecture in the same theatre on Fergusson's system, in which, after pointing out the most striking advantages of the system,' he declared that he could confidently leave it to work its own 'way to success.' This lecture is, by permission of Colonel Adams, appended to the Peril of Portsmouth.'

To an uneducated eye the lines of a fortress present a complication of zig-zags most difficult of comprehension; we will endeavour in a few words to make their object clear.

The great principle of the modern system of fortification is

to prevent the approach of an enemy within the extreme point of depression of the guns mounted on the walls; and for this purpose, every face or front of the works is so placed that it is flanked or enfiladed by the guns on some other face. This, called the bastion system, which in theory is beautiful, almost perfect, entirely fails in practice to fulfil the conditions required in a fortress: so infinitely superior is the science of attack to that of defence, that the military engineer can calculate almost to a day the time required to reduce any place. The main defects of this system are, the insecurity of its flanking defences from their liability to be enfiladed, and the inability to use direct fire from the salient, and therefore the most exposed points. Accordingly, the first operation in a siege, after establishing the first parallel, is to erect batteries on the prolongation of the faces flanking the part to be approached; and the zig-zags between the parallels are carried forward in front of the salients or capitals of the bastions, whence there can be no direct fire on them.

The principle of Mr. Fergusson's system is, by enabling the fort to bring a preponderance of fire on any point, to overwhelm the batteries of the besiegers. To obtain this end, he rejects bastions and outworks, and replaces them with a work of a curvilinear outline, adapted to the form of the ground; and from a very wide and deep ditch, procures earth to form a mound from 60 to 80 feet high; this mound he fashions into four tiers of ramparts, the first on the level of the country, the others rising sixteen feet one above the other. Colonel Adams calculates that a Fergusson fort can bring nearly 100 guns to bear on any point at a distance of 600 yards, if the embrasures are cut to allow a gun to traverse 20° each way. A second great advantage claimed for this system is its immunity from enfilade. A third great advantage is the economy of its construction as compared with a fort having masonry revêtements; the expense of the masonry of a front of fortification being from 60,000l. to 80,0007., while the earth-work is only 3,000l. or 4,000l. In a Fergusson fort there is but little masonry, but a larger amount of earth-work, and a much greater expenditure in ordnance; when completed, however, it is calculated not to have cost one fourth of the sum required for a bastioned fort on the same ground. A fourth advantage claimed for this system, and one of great importance in this country, is, that it does not require a garrison of disciplined soldiers; the sole manœuvre being the working of the guns, a proportion of artillerymen only is required, the remainder may be composed of infantry, militia, seamen, coast-guard men, and dockyard battalions.

The most important objections raised against this system are,

the complete immunity of the besieger from sorties, and the consequent facility he will have in making his approaches, even up to the edge of the ditch; that not only are the lines of a Fergusson fort open to a destructive enfilading and ricochet fire, but that from the magnitude of the mark, this fire may be maintained as efficiently by night as by day, while the enfilading batteries would be perfectly protected by thick épaulements from the fire of the fort; that riflemen in pits would silence every gun in front of them; and lastly, that the cost is vastly underrated. We conceive that Colonel Adams has refuted the former of these objections in his lecture; but, on the score of cost, we will offer a few remarks, for that is one of the strongest arguments for the application of Mr. Fergusson's system to defensive works in this country. His estimate for the cost of a work in front of Gosport, to which we shall allude presently, is 200,000l. A critic, who is said to be an officer of the highest professional and practical ability, has objected that this estimate would be exceeded twice or thrice. We may grant this point, but the non-professional reader will be surprised to learn that the same line fortified according to the rules of fortification would cost little, if any thing, less than 1,000,000%.†

Amongst the critics of the Fergusson system of fortification, the author of A Flying Shot at Fergusson' deserves mention. It is a very amusing little brochure, more replete with jokes than arguments, in which the gallant author does, to his own evident satisfaction, completely demolish a Fergusson fort. It is remarkable that although Colonel Jebb is startled' at a civilian claiming to have discovered that which for many a long year has puzzled the most eminent engineers: viz., how to restore to the defence the superiority it possessed over the attack previous to the

In the U. S. Magazine for February, 1853.

† Since the above was written, we have read some remarks by Lieutenant-Colonel Portlock, R.E. (at page 281. of Colonel Chesney's 'Observations on Fire Arms',) on the changes in the system of defensive works, which will result from the modern improvements, giving greatly increased range, and accuracy of fire to small-arms. The Colonel infers that the Engineer will gain some one of the following advantages in all fortresses.

1. The power of using larger lines of defence.

2. The diminution in the number of salients.

3. The power of uniting naturally strong and salient points, by simple lines, without intervening salients.

4. An effective co-operation of cannon and musketry in defence. Thus, Colonel Portlock, arguing from entirely different premises, makes a near approach to the principles of the Fergusson System.

invention of gunpowder: and although he satirizes, with some degree of justice, Mr. Fergusson's assumption of impregnability for his system; he yet makes a statement which clearly admits the superiority of that system over those hitherto in use; for in describing his method of attacking such a fortress (p. 16.), he tells us, that in order to evade the overwhelming fire of the besieged, he should adopt the novel expedient' of placing the besiegers' guns in 'sunken batteries seven feet deep, without any parapets,' and so afford the besiegers a less definite object to fire at. The Colonel likewise admits (p. 1.), that Mr. Fergusson is supposed to have had the best of the discussion at the United Service Institution, and his flag still flies triumphant ' on his so called impregnable fortress.'

We will now proceed to consider how Mr. Fergusson proposes to apply his system to the defence of Portsmouth. The land defences consist of three separate and distinct lines of fortification, ⚫ the oldest being those of Portsmouth, the trace of which belongs 'to the age of Charles II. and William III., though somewhat improved since their days; those of Portsea are of the time of George III., and very far superior, both in trace and profile; while those of Gosport are little better than field-works, con'sisting merely of an earthen rampart, unrevêted, and without ' outworks; the only defence against even an attack de vive force being a shallow cunette of very miserable dimensions.' (P. 31.) We need not here consider the works of Portsea and Portsmouth toward the land, the island of Portsea being by nature so difficult of access, as to require but little to make it almost impregnable on that side. Gosport is the weak point, and the very inefficient works there, being still further weakened by the ground in front of them being built over, within musket shot, such cover is afforded to an attacking force that it is probable they would be carried by a coup-de-main, when the harbour and dockyard would be laid at the mercy of the enemy. It may be observed, that if our fleet were decoyed to a distance by a simulated attack elsewhere, there could be little resistance offered to an enemy disembarking west of Stokes Bay. The Government plan for improving the defences, so far as it is at present developed, consists in the erection of a fort, estimated to cost 45,000l. It is said that three principal works, connected by smaller forts, are to form a line of defence from Elson's Hard to Stokes Bay, about 2000 yards in front of the dockyard. If this be correct, then the estimate for the whole will probably far exceed that of the work proposed by Mr. Fergusson.

Mr. Fergusson proposes to form a line of defence on his system, as above described, from Frater Point on the harbour,

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