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 Notes on sea-coast defence: 
 
 ^|.^ 3 1924 030 759 Sas'"' 
 
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 Library 
 
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 tlie Cornell University Library. 
 
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NOTES 
 
 SEA-COAST DEFENCE: 
 
 CONSISTING OF 
 
 SEA-COAST FORTIFICATION, 
 
 THE FIFTEEN-INCH GUN, 
 
 CASEMATE EMBRASURES. 
 
 Major JT G. BARNARD, 
 
 V. S. COErS OF ENGINEERS. 
 
 NEW YORK: 
 
 D. VAN NOSTRAND, 192 BROADWAY. 
 
 1861. 
 
GENERAL JOSEPH G. TOTTEN, 
 
 CHIEF KNGINEER U. S. ARMY, 
 
 THE3G PAQBS ARK 
 
 $«»perfMg Inscrikb. 
 
CONTENTS. 
 
 I. ' Sba-coast Fortification, ..... 9 
 
 II. The Fifteen-inch Gun ; an account of the same, with 
 considerations as to the probable uses of guns of 
 extraordinary calibres for sea-coast defence, . . 31 
 
 III. Casemate Embrasures ; an account of the facts and 
 principles which have governed the design of the 
 " American Embrasure," and a review of Sir How- 
 ard Douglas's strictures on the same, in the 5th 
 edition of his " Naval Gunnery," . . . .61 
 
The march of invention and improvement in 
 all the machinery of war has been so rapid, of late 
 years, as to make necessary frequent scrutiny of all 
 existing " systems," whether of military organiza- 
 tion or construction, lest they should be found no 
 longer adapted to their purposes. 
 
 Indeed, it is more common by those who would 
 be regarded as illuminated by the new lights of the 
 age to lay the charge of "obsolete" against such 
 systems than to scrutinize their validity. 
 
 The existing system of American " Sea-coast 
 " Defence " has been always a chosen subject mth 
 such. To examine whether it is stiU a safe reliance 
 for the nation, and whether it is capable of op- 
 posing to new and probable means of attack new 
 and sufficient counteracting agencies, — to ascertain, 
 in fact, whether it has in itself a faculty of adapt- 
 ation to the changes of the times, without which 
 nothing old can long survive, — is the object of 
 these "Notes." 
 
SEA-COAST FORTIFICATION. 
 
Sea-Coast Fortification. 
 
 It is well known tliat important steps have 
 recently been taken in England towards the more 
 perfect defence of the great maritime arsenals and 
 dock-yards. No less a sum than some fifty millions 
 of dollars has been appropriated by Parliament to 
 the immediate construction of fortifications for 
 Woolwich, Chatham, Sheerness, Dover, Portsmouth, 
 Portland, Plymouth, and Pembroke. 
 
 Whether we consider this as but an incidental 
 measure connected with the general defence of 
 the country against the much-talked-of invasion 
 by France, or whether we regard it as simply a 
 step, now become necessary, for the security of 
 those great establishments at which the pro- 
 posed works are to be located, it is equally full 
 of interest to those who have been concerned 
 in the American system of defences. Indeed, it 
 would seem as if England had waited until all 
 
12 SEA-COAST FOETIFICATIOK. 
 
 the changes of opposition had been rung by 
 the critics of our system, to send us this, her 
 practical answer, to such arguments as have been 
 founded upon her example, and, at a period when 
 she can no longer refrain from adopting a thorough 
 system of coast defence, to give in her adhesion 
 to the great principle upon which our system was 
 founded forty-five years ago, and upon which it has 
 undeviatingly been prosecuted. Barely twenty 
 years have elapsed since the, then, highest military 
 authority of the government — a man whose public 
 services, military and civil, added much to the 
 weight which his high position gave to his stric- 
 tures upon our system of fortifications — asserted, in 
 an official report, — 
 
 " 1. That, for the defence of the coast, the chief 
 " reliance should be on the navy." 
 
 " 2. That, in preference to fortifications, floating 
 " batteries should be introduced wherever they 
 " can be used." 
 
 " 3. That we are not in danger from large ex- 
 " peditions, and, consequently, 
 
 " 4. That the system of the Board of Engineers 
 " comprises works which are unnecessarily large for 
 " the purposes they have to fulfil." 
 
SEA-COAST rOETIFICATION. 13 
 
 Commodore Perry, a Mgli authority, whose 
 opinions have not wanted participators, especially 
 among naval men, expressed, at a still more recent 
 period (but eight years ago), his belief that naval 
 meoMs should be principally relied on for our de- 
 fence, and enforced his opinions by the example 
 of England : — 
 
 " Of all the coasts of Europe, that of Great 
 " Britain is the least provided with fortifications ; 
 " and yet her soil has not been trodden by a suc- 
 " cessfal enemy since the conquest; solely pro- 
 " tecting her military and naval arsenals by per- 
 " feet and well-ga/rrisoned works. She depends 
 " mainly for defence of her coast upon her navy 
 " and the warlike spirit of her yeomanry ; and the 
 " very absence of fortified works prevents a de- 
 " ceitful reliance upon such defences, and keeps 
 " alive the more gallant and more certain depend- 
 " ence upon their own personal prowess." 
 
 Such opinions, though they are not entirely 
 abandoned, have now so few supporters that it 
 would be wasting ink and paper to quote them 
 for confutation ; but, at least, we may find in their 
 history the ground for confirmed belief that the 
 system which has thus outlived the adverse opin- 
 ions of its ablest critics — even though a new class 
 
14 SEA-COAST FOETIFICATION. 
 
 has recently arisen, to announce the brilliant dis- 
 covery, that all stone walls are but "crockery" 
 against the newly-invented missiles which modem 
 military science will hurl against them — ^is still 
 the true one. So far from having become " anti- 
 quated" and "obsolete," the very nation whose 
 exemption from its "chained monsters" has been 
 so vauntingly cited, has at this recent date indorsed 
 it, even to the extent of its "masonry casemated 
 castles." We will let the British Commissioners 
 state their own case.* 
 
 " During the wars in the early part of this cen- 
 " tury, when the 'strength of the Royal Navy had 
 " attained an extraordinary development, it was 
 " equal to the performance of all the duties im- 
 " posed upon it ; but it appears doubtful to your 
 " Commissioners, having regard to the present state 
 " of continental navies, whether even a fleet of such 
 " magnitude as we then possessed would now be 
 " able to perform them all efficiently. A much 
 " larger proportion would be required for purely 
 " defensive purposes than previously, owing to the 
 " certainty with which the movements of fleets 
 " can be combined by the aid of steam, and the 
 
 * See Keport of Commissioners appointed to consider the Defences of 
 the United Kingdom, <tc. London, 1860. 
 
SEA-COAST FORTIFICATION. 15 
 
 " rapidity with which a large force can be concen.- 
 " trated at a given time on any point. Even if 
 " it were possible that a fleet sufficient to meet 
 " the emergency of a sudden naval combination 
 " against this country could be kept available, and 
 " fully manned in time of peace, such an applica- 
 " tion of the resources of the nation would lead 
 " to an outlay of the public revenue far exceeding 
 " the expenditure which would suffice for that ob- 
 " ject under other circumstances. The first cost 
 " would be very great, and the necessary expense 
 " for maintenance would be continual, involving 
 " the employment of a large additional number of 
 " trained seamen, — a class of men who can with 
 " difficulty be obtained, and who are necessarily 
 " the most costly of any branch of the military 
 " service, owing to the various qualifications re- 
 " quired of them. A periodical renewal of the 
 " entire fleet would, even under ordinary circum- 
 " stances, be requisite about every thirty years, 
 " without regard to those changes which are un- 
 " avoidably caused by the present transitional state 
 " of naval architecture, and the rapid progress of 
 " mechanical science, in which changes we are 
 " compelled to take the lead in order to maintain 
 " our maritime supremacy." 
 
16 SEA-COAST FOBTIFIOATION. 
 
 It is not strange, then, that the Commissioners 
 have foimd it necessary to admit that a system 
 of purely naval defence " is one which could not 
 " be entirely relied upon at the preselit day, even 
 " if England had no greater external interests to 
 " protect than the countries which may be op- 
 " posed to her." 
 
 To estimate fully the real importance of such 
 conclusions, at this date, on the part of England, 
 it is necessary to consider that our own system 
 was inaugurated at a period when, compared with 
 England — with ourselves^ even, as we are now — ^we 
 were a weak nation, with an extensive seaboard 
 to defend against maritime attack. Even if the 
 immense naval means of England had been a safe 
 reliance (at that date) for her, the utter disparity 
 of our own naval power would have made it un- 
 reliable for us. At best, the fact would have 
 only raised the alternative whether, for our coast 
 defence, we should create a navy (proportionally) 
 as great as that of England, or whether we should 
 resort to fortifications. We adopted the latter al- 
 ternative; and we did so, not simply because we 
 had not a large navy, but because we based our 
 defensive system upon the broad principle that 
 naval means were not the true means of coast 
 
SEA-COAST FOETIFICATION. IV 
 
 defence ; that to give fall efficiency, even, to our 
 navy, and to set it free to fulfil its higlier destiny 
 of protecting abroad our rights and our commerce, 
 and of extending the weight of our arms to the 
 enemy's own shores, our cities and harbors must 
 he defended by fortifications. 
 
 On the other hand, England, during the quar- 
 ter-century's wars growing out of the French Kev- 
 olution, had annihilated the navies of Europe; 
 and the peace of 1815 found these nations, one 
 and all, so exhausted, that her shores would haA^e 
 been safe, for a period at least, with neither for- 
 tifications nor extensive naval means. As years 
 elapsed and the nations of the continent (France 
 especially) recuperated, and ideas of new contests 
 revived, there was yet much to give great security 
 to the shores of England without giving any 
 greatly increased development to her fortifications. 
 Her navy had, still, greatly the preponderance ; 
 and if the narrowness of the channel seemed to 
 give great facilities to France for a hostile descent, 
 yet, in the days of sailing vessels, this circum- 
 stance was perhaps inore than compensated by the 
 ease with which the whole coast of France could 
 be watched and every French port blockaded by 
 the powerful navy of England.* The fact, there- 
 
 " Yet, to show how unreliable this species of defence ia, even when 
 3 
 
18 SEA-COAST FOETIFICATION. 
 
 fore, tliat England lias Htterto been able to do 
 without very extensive woAs of sea-coast fortifi- 
 cation * is not an argument that fortifications are 
 not, j)er se, the most reliable and the cheapest of 
 all means of harbor defence. 
 
 But whatever argument might have been drawn 
 from the example of England, in past years, she 
 furnishes now the most striking example that 
 could be offered to us of the truth of our funda- 
 mental principle, that the essential and true, basis 
 of coast defence is fortification. Through her Com- 
 missioners, she declares "That it would be very 
 " unsafe to rely on the experience of former wars 
 " in judging of this question. Since the peace of 
 
 there is every warning of a threatened invaaion, and every possible de- 
 fensive means which an immense navy affords is taken, witness the in- 
 vasion of Ireland, in 1796, by Hoche. Three powerful fleets were on the 
 lookout for this expedition, yet it g'ot out unnoticed, and, after eight days' 
 passage, landed 25,000 men at Bantry Bay (occupying three days in so 
 doing). Of the forty-four vessels, only one was intercepted by the En- 
 glish squadron. Well does Allison say that the empire of the seas does 
 not afford security against invasion. 
 
 * It would seem as if those who have referred so much to the ex- 
 ample of England supposed she had never had fortifications at all. 
 From the very earliest days of her maritime greatness she commenced 
 fortifying her shores. Plymouth, Portsmouth, Dover, and other great 
 ports, have not only been protected seaward by fortifications, but are 
 enveloped in continuous enceintes for land defence, which date back to 
 the lYth century. These works have, for the last forty years, been con- 
 stantly added to, while almost a continuous range of MarteUo towers 
 overlooks the waters of the channel. 
 
SEA-COAST FOETIFICATION. 19 
 
 " 1815, the state of naval warfare has been revolu- 
 " tionized. The introduction of steam may operate 
 " to our disadvantage in diminishing to some ex- 
 " tent the value of superior seamanship ; the effi- 
 " cient blockade of an enemy's ports has become 
 " well nigh impossible ; the practice of firing shells 
 " horizontally, and the enormous extent to which 
 " the power and accuracy of aim of artillery have 
 " been increased, lead to the conclusion that, after 
 " an action, even a victoi'ious fleet would be more 
 " seriously crippled, and, therefore, a longer time 
 " unfit for service." And again they say, " Since 
 " the application of steam to the propulsion of 
 " vessels, we can no longer rely upon being able 
 " to prevent the landing of a hostile force in the 
 " country;" and, finally, after examining all otJie)' 
 defensive means, they state their conclusion as 
 follows : — 
 
 " Having carefully weighed the foregoing con- 
 " siderations, we are led to the opinion that neither 
 " our fleet, our standing army, nor our volunteer 
 " forces, nor even the three combined, can be re- 
 " lied on as sufficient in themselves for the secur- 
 " ity of the kingdom against foreign invasion. 
 " We, therefore, proceed to consider that part of 
 
20 SEA-COAST FORTIFICATION. 
 
 " our instructions wHcli directs our attention espe- 
 " cially to fortifications." * * * * 
 
 * * * * "We are tlius led to tlie 
 " conclusion, tliat by a judicious application of 
 " fortifications the means would be aflSorded of 
 " utilizing, in tlie highest degree, both our fleet 
 " and the regular army, and the forces which 
 " would be brought in aid of it ; and, further, 
 " that without fortifications there is no mode of 
 " defence which can be proposed that would give 
 " the same amount of security to the country, and 
 " at the same time be so economical both in 
 " money and troops." 
 
 The Commissioners, having thus decided that 
 a more extensive system of fortifications was ne- 
 cessary for the security of England, proceed to 
 lay down the principles which should govern their 
 location and extent. They are essentially identi- 
 cal with those adopted by our own engineers. 
 They state that " The fortifications of this country 
 " should be confined, chiefly, to the protection of 
 " those vital points at which an enemy would 
 " strike, and of harbors whose possession would 
 " give him sure bases of operations in positions 
 " favorable to his designs." 
 
SEA-COAST FOKTIFICATION. 21 
 
 " There are also certain harbors wHch, although 
 not of sufficient consequence to be used by them- 
 selves as bases for extensive operations, would 
 nevertheless, afford an enemy, if he possessed 
 them, facilities for landing guns, horses, and 
 materiel ; and at these it appears advisable to 
 have some degree of permanent defence, in order 
 to deny their use to him, and cause him some 
 delay by restricting his operations to the open 
 beach until he had succeeded in capturing the 
 defences. It is desirable, also, that works of de- 
 fence should be provided for our commercial 
 ports. The security of several of these would 
 be of the utmost moment to the trading interests 
 of the country ; and others have a military value, 
 independent of their commercial importance ; but 
 ports of this character are not subject to attacks 
 on a great scale, such as would be brought to 
 bear on the royal naval establishments. The 
 measures for their defence would be of compara- 
 tively small extent." 
 
 They regard the dock-yards as the vital points 
 of coast defence, while places of mere commercial 
 importance — even such as Liverpool — require less 
 means of defence. But while the great dock-yards 
 are considered as vital points — ^points which, in 
 
22 SEA-COAST FOBTIFICATION. 
 
 view of the important consequences of their capture 
 or destruction, would, in themselves, invite an at- 
 tack in force — it is London which they consider the 
 trv£ vital point of England, in reference to French 
 invasion. " There can be no doubt," they say, 
 " that the main object of an enemy invading the 
 " country would be to push for the capital, in the 
 " hope that if he succeeded in obtaining command 
 " of it, such a disaster would result in our buy- 
 " ing him off upon any terms he might think it 
 " expedient to exact." The Commissioners do not 
 indeed take up directly the question of the de- 
 fence of London, since it formed no part of their 
 instructions to do so ; but they consider the forti- 
 fication of the coast — i. e., the harbors and dock- 
 yards — as, in itself, an indispensable step towards 
 the defence of London. 
 
 We have no single place corresponding in all 
 respects to London, — ^the political capital of the 
 nation — ^the commercial capital of the world. But 
 we have places which will be almost as truly the 
 vital points of the war vidth a great maritime 
 power as London is that of England. 
 
 In a paper on the "Dangers and Defences of 
 New York," the writer attempted to show that 
 in future all war of maritime powers against the 
 United States will be directed against om- great 
 
SEA-COAST FORTIFICATION. 23 
 
 sea ports, and particula/rly New York. Tlie de- 
 fence of New York is indeed, to us, thongh. in a 
 somewhat less degree, what that of London is to 
 England. It may be said of New York, as of Lon- 
 don, that if an enemy "succeeded in obtaining 
 " command of it," even temporarily, — or, what 
 would be nearly the same in its consequences, if 
 he succeeded with his fleet in forcing the entrance 
 to the harbor, and in bringing his guns to bear on 
 the city, " such a disaster would result in our buy- 
 " ing him off upon any terms he might think it 
 " expedient to exact." Attacks upon other great 
 sea-port towns, such as Boston or Philadelphia, 
 might, indeed, be attended with results highly dis- 
 astrous, but they would tell comparatively little 
 upon the issues of the war. The difference is that 
 between striking a limb and striking the heart, for 
 New York is the true heart of our commerce — the 
 center of our maritime resources; to strike lier 
 would be to paralyze all the limbs. As a power- 
 ful maritime enemy will select that point where 
 the effect of his blows will be most disastrous ; as, 
 in proportion to the resistance he anticipates, he 
 will prepare himself for the attack, we may be 
 sure that New York would be the scene of re- 
 peated and terrible struggles, ceasing only to be 
 renewed again as long as a war should last; un- 
 
24 SEA-COAST FOETIFICATION. 
 
 less, indeed, our defensive system is so impregnable 
 as to make attacks hopeless. It was under suet 
 convictions that tlie following paragraph was writ- 
 ten in the " Dangers and Defences :" 
 
 " The mere defence of the city against ordi- 
 " nary fleets is no longer the questipn ; but, through 
 " the def&nswe worhs to he here erected, the nation 
 " is to measv/re its strength against the most la/oish 
 " use of the resowces of a great maritvme power, 
 " aided hy all that modern science amd mechanical 
 " ingenuity, in creatvng or inventing m,eans of at- 
 " tacTc, can hring against them / in short, in forti- 
 " fying New York, we are really prepa/ring the 
 " hattle field on which the issue of futv/re mom,entous 
 " contests is to be decided.^'' 
 
 If, therefore, there is anything real and earnest 
 in our prepa/ration for war, it is New York that 
 most urgently and speedily demands that the prep- 
 aration shall be rendered complete. Let her be 
 completely defended and we need fear little from 
 efforts elsewhere. But, however complete our prep- 
 arations elsewhere may be, we are yet exposed to 
 all the worst consequences of a maritime attack 
 until New York is made impregnable. 
 
 As to the methods of defence, we are not to 
 
SEA-COAST FORTIFICATION. 2o 
 
 look to London, for that involves considerations 
 of locality quite different from those that belong 
 to New York. But we may turn to Portsmouth, 
 vi^ith its external anchorage of Spithead, for an 
 example having in its local characteristics anal- 
 ogy with New York, and as the greatest naval 
 depot and dock-yard of England, — an importance 
 to the national defence second only to that of 
 London. 
 
 It has been stated that, although England has 
 been so often cited as an example of reliance upon 
 naval means alone for coast defence, she has never 
 trusted the secuiity of her great naval establish- 
 ments nor more important harbors entirely to such 
 means. The towns of Portsmouth and Portsea 
 were, in the 17th century, surrounded by a con- 
 tinuous bastioned enceinte, while the entrance to 
 the harbor and approaches are defended by works 
 which have been constructed at different periods. 
 Some of these last works are casemated — some 
 open, or barbette batteries. So extensive are these 
 works at the present moment that, so far as the 
 " immediate defence of the entrance " or a landing 
 on the adjacent shores is concerned, the Commis- 
 sioners find that little more is needed. 
 
 The spacious external anchorage of Spithead 
 (presenting much analogy to the Lower Bay of 
 
26 SEA-COAST FOKTIFICATION. 
 
 New York), of vast importance to the navy of En- 
 gland, and a position from wHcli the dock-yard can 
 be bombarded, is entirely defenceless. This an- 
 chorage between the Isle of Wight and Portsmouth 
 is too broad, and too far distant from the land, to 
 be reached by shore batteries. Here, at the very 
 heart of the naval opulence of England, one would 
 think that if " naval means " were at all reliable 
 or admissible such means would have been re- 
 sorted to. That they are not reliable, unaided by 
 forts, may be best judged by the fact that, for this 
 defence, fA)e " masonry casemated castles " are to 
 be built on shoals covered by several fathoms of 
 water, and the Commissioners " Recommend that 
 " the more important of these works should be 
 " built with three tiers of guns in casemates, with 
 " guns and mortars on the roof. The adoption of 
 " such a mode of construction will add consider- 
 " ably to the amount of fire that can be brought 
 " to bear on any point, and will give the upper tier 
 " of guns command over the decks of the attack- 
 " ing ships — an advantage which will be obtained 
 " at a comparatively small addition to the total 
 " cost of the work when the foundations have been 
 " completed. These batteries should be built of 
 " masonry, faced with hard granite; the embrasures 
 " should be of wrought iron, and of as small dimen- 
 
SEA-COAST FORTIFICATION. 27 
 
 " sions as possible, compatible with tlie free worlc- 
 " ing of a gun." 
 
 One might almost think that an American en- 
 gineer had penned the above paragraph, so truly 
 are the principles which have governed us, in 
 similar cases, adopted ; not that we consider " ma- 
 " sonry casemated castles " of quadruple tiers of 
 guns as absolutely the hest way of arranging guns, 
 but that in such localities, where space cannot be 
 had, they are the best for the circumstances. The 
 idea of "embrasures of wrought iron, and of as 
 " small dimensions as possible," is evidently derived 
 from our model embrasure, such as may be seen at 
 Fort Eichmond. 
 
 Such are the results at which English Commis- 
 sioners have arrived, and their report has been gen- 
 erally approved by the British public, adopted, and 
 funds to the amount of fifty millions of dollars, as 
 before stated, voted in Parliament for the imme- 
 diate execution of the works recommended, and 
 the system of defences is now in the course of 
 execution. Critics may scoff at it if they choose, 
 but at least they cannot allege, as they sometimes 
 do, in reference to our system, that it was devised 
 before the days of steam — of rifle-cannon — of iron- 
 clad floating batteries. All these things they are 
 thoroughly acquainted with. They had, too, the 
 
28 SEA-COAST FOBTEFICATION. 
 
 recent experience of the Russian war, in wHcli the 
 efficiency of Russian fortifications had teen so 
 thoroughly tested. The repulse of the attack of 
 the allied fleet before Sebastopol, and the extraor- 
 dinary paralysis with which the combined fleets of 
 England and France — ^the mightiest naval arma- 
 ment the world ever saw, headed by the boastful 
 Napier — were smitten at the sight of the " masonry 
 casemated castles " of Cronstadt, were fresh in their 
 recollection. They knew all that had been done 
 and all that has been proposed to be done with 
 " iron-clad floating batteries," and e^^dently were 
 not impressed with the conviction that they were, 
 or even could le made, a match for fortifications.* 
 
 It is flattering to the military pride of our na- 
 tion — ^it is satisfactory to our own sense of security 
 — to find that the principles of coast defence which 
 we for the first time laid doA\Ti nearly a half-cen- 
 tury ago are, at this date, adopted by that nation 
 whose immunity from coast defence has been so 
 
 • Not only can our masonry batteries be protected, if it ever becotnes 
 necessary (which I consider it far from being at the present time), by the 
 same means which are resorted to for the floating structure; but we 
 know that we can direct against these (so-called) shot-proof structures a 
 shot which will stave in the sides, carry as much iron as she may on 
 them consistently with floating. I allude to Captain Rodman's success- 
 ful construction of a 15-inch gun which Tyill doubtless soon be introduced 
 into our fortifications. 
 
S;EA-C0AST rOETIFICATIOIf. 29 
 
 long boasted, and that the mecms of defence re- 
 sorted to are identical with those we have been 
 and are still applying to our own coasts. Would 
 that we could still further be an example in the 
 promptitude with which we complete a system long 
 since undertaken. Though we may not plead the 
 urgency which the English nation feel in perfect- 
 ing their defences, it is at least highly important 
 that that one point — New York — upon which the 
 stress of maritime war will surely fall, should be 
 promptly made perfectly defensible. 
 
 Before closing this paper it will be profitable 
 to turn back again to the criticisms or " objections " 
 which have been raised at different periods. The 
 quotation already made on a former page gives 
 the objections of the head of the War Department 
 — one of the then most prominent military author- 
 ities in the country. They are a full expression 
 of the hostility of that day to the system. 
 
 It is somewhat amusing to find that at the 
 present day the first two propositions (long since 
 abandoned by naval officers* as untenable) are 
 
 * Of the numerous distinguished British naval officers (all of whom 
 had seen service against fortifications either in the Black Sea or Baltic, 
 or otiier of the remarkable actions of that kind in which England has 
 been engaged) there was not one who would rely on "naval means'' or 
 "floating batteries" alone. All recommended fortifications. 
 
30 SEA-COAST rOETIFIOATION. 
 
 now renounced by the very nation whose immunity 
 from danger behind her floating walls has been so 
 often appealed to, — the very nation, too, whose 
 " naval means " surpass those of all the rest of 
 the world,^ — and that some rec&nt critics of our sys- 
 tem take exactly the reverse position from the last 
 propositions, and assert that we are "in danger 
 " from large expeditions," and pronounce most of 
 our works " weak and contracted," particularly on 
 their land sides, — ^while still another class think 
 that our forts need not even have a defensible front 
 towards the land. 
 
 With the substantial proofs which we now have 
 of the wisdom and foresight of those who, half a 
 century since, inaugurated our system — of its entire 
 adaptedness to our present circumstances, we can 
 well aiford to leave criticism to do as it has so 
 repeatedly done, — confute itself. 
 
. . THE FIFTEEN-mCH GUN. 
 
The Fifteen-Inch Gun. 
 
 The fifteen-incli gun, now at Fort Mom-oe, was 
 cast at the Fort-Pitt foundry of Messrs. Knapp, 
 Rudd & Co. (Pittsburg), under the direction and 
 after the method of Captain T. J. Rodman, of the 
 ordnance corps, to whose perseverance, zeal, and 
 laborious investigations the successful result is 
 mainly due. 
 
 Its dimensions are as follows : 
 
 Total length of gun, . . , . 
 
 190 inches 
 
 Length of calibre of bore, 
 
 156 " 
 
 Length of ellipsoidal chamber, . 
 
 9 " 
 
 Total length of bore, .... 
 
 165 " 
 
 Maximum exterior diameter. 
 
 48 " 
 
 Distance between rimbases, . 
 
 48 " 
 
 Diameter at muzzle, .... 
 
 25 " 
 
 Thickness of metal behind the chamber, 
 
 25 " 
 
 Do. at junction of bore with chamber, 
 
 16i " 
 
 Do. at muzzle, .... 
 
 5 " 
 
 Weight of gun, .... 49,100 lbs. 
 5 
 
34 THE FIFTEEN-INCH GUN. 
 
 The unprofessional reader may ask, " Why more 
 " difficulty in making a gun of this calibre than a 
 " smaller one ?" So far as the mere casting of so 
 mv/iTi metal is concerned, there is none at all. But 
 it is found, practically, that guns of large calibre, 
 cast by the ordinary methods, have not the requi- 
 site strength to bear the strain to which they must 
 be subjected in firing. This is mainly owing to 
 the fact that melted iron slirinks in cooling, and 
 that (when the mass is large) the process of solid- 
 ifying is not simultaneous throughout the mass, 
 but is progressive from the surface inwai-ds. By 
 the usual methods, guns ai"e cast solid and then 
 bored out. The effect of this solid casting is, that 
 the outer shell fii'st cools and becomes solid, while 
 the interior is still liquid. As the interior cools it 
 produces by its contraction a strong compression in 
 the outer and first solidified portions. The outer, 
 already solid crust, being unable to follow the con- 
 traction of the inner mass, the latter becomes solid 
 in a state of high tension, and, when the mass is 
 large, not infrequently forms flaws and cavities. 
 So long as guns of small calibres only were used, 
 the evils of this method did not exhibit themselves 
 to such an extent as to prevent ordnance thus made 
 from being perfectly serviceable. But even with 
 
THE FIFTEEN-INCH GUN. 35 
 
 small calibres it is obvious that about tlie surface 
 of the bore, where the greatest strength and greatest 
 hardness is required, the metal is the least dense 
 and the least hard of the whole mass ; and it is ow- 
 ing to this fact that guns become so soon unservice- 
 able, by the enlargement of the bore around the 
 seat of the ball, after prolonged firing. Indeed, this 
 enlargement is readily detected and measured (by 
 delicate instruments especially adapted to the pur- 
 pose), and is almost invariably found to have oc- 
 curred in the best solid-cast guns after a few hun- 
 dred rounds of firing. As the firing is prolonged, 
 the enlargement of the bore is observed to pro- 
 gress ; the state of compression (already mentioned) 
 in which the cooling process leaves the outer crust 
 of the gun actually aids the internal eifort of the 
 powder, and, after a certain number of rounds (from 
 one to two thousand) with full charges, the gun 
 bursts. 
 
 The greater the mass of the casting — that is, the 
 greater the calibre of the intended gun — the greater 
 are the irregularities of structui'al arrangement 
 caused by this manner of casting, and the more in- 
 adequate does the gun become to resist the strain 
 to which it must be subjected. Hence the (hither- 
 to) practical limit to the calibre of cast-iron guns. 
 
36 THE FIFTEEN-INCH GUN. 
 
 No nation in the world lias succeeded in making 
 serviceable guns of more than 10 inches calibre.* 
 
 Captain Rodman's method consists especially in 
 casting the gun Jwllow instead of solid, and — by 
 means of a current of water introduced into the core 
 which forms the mould of the bore — cooling from 
 the interior. To ensure the cooling shall be exclu- 
 sively internal, the exterior of the mould is kept 
 heated during the whole process. The effect of this 
 is easily seen to be that the interior metal (imme- 
 diately about the bore) solidifies first^ and, as "the 
 more distant portions solidify, there is nothing to 
 oppose their contraction; they, therefore, assume 
 the solid state without causing those injurious 
 strains in the metal caused by the old process. In 
 reality, when the cooling is properly managed, the 
 interior metal about the bore is in a state of covn- 
 pression and the exterior in a state of tension ; ex- 
 actly as theory shows it should he to get the Tnaooi- 
 mwm si/rengih of the whole thickness of metal 
 when subjected to internal strain. Not only this, 
 but the metal about the bore first cooled and in 
 constant contact with the cooling medium is, as it 
 
 * Dahlgren's gtms for naval service are of H inches calibre. Thoiigh 
 they -vrill project a solid shot with light charges, their principal use is as 
 a shell gon. 
 
THE riFTEEIf-INCH GUN. 37 
 
 should he, the hardest and densest. By the solid 
 casting process it has been shown that the results 
 as to both these conditions — of tension and of hard- 
 ness — were just the reverse. Hence the practical 
 limit to increase of strength with thickness by that 
 process.* These theoretical considerations have 
 been fully confirmed by experiment. Several guns 
 of smaller calibre were cast and subjected to severe 
 tests previous to attempting so unusual a calibre. 
 The 15-inch gun of which I now speak has been 
 subjected, up to present date, to 350 rounds with 
 full charges.f At the 300th round (no later meas- 
 urement has been made, I believe) the delicate tests 
 applied to the bore failed to indicate the slightest 
 enlargement or deterioration of any kind. 
 
 The gun now at Fort Monroe is mounted upon 
 an iron centre-pintle carriage, the top carriage of 
 which recoils upon the rails of the lower one, and 
 permits, by a ratchet cut in the breech of the gun, 
 an elevation of about 28^°. The rails of the lower 
 
 * " Mr. "Whitworth predicted, truly, as it has since appeared, that iron 
 " guns, cast in solid masses, would be found incapable of resisting the great 
 " strains to which rifled cannon are subject ; it being well known that great 
 " ine(iualities in the physical structure of the metal are produced during the 
 " process of cooling, and that, beyond a certain limit, little or no increase 
 " of strength is given to the gun by increasing its thickness of metal." — 
 (Naval Gunnery.) 
 
 f The average charge has been 35 lbs. of large-grained powder, with 
 shells of 805 to 335 lbs. weight. 
 
38 THE rrPTEEK-iNCH Ginsr. 
 
 carriage being inclined, tlie gun runs forward, of 
 itself, from tlie position of recoil into battery, on 
 rollers attached to an eccentric axis, easily brought 
 to bear by two men with band-spikes. Notwith- 
 standing its great weight, it was easUy manipulated 
 by a firing party consisting of a sergeant with six 
 men. 
 
 When fired horizontally, or nearly so, the time 
 of loading and running into battery was, in one 
 case, 1' 10" ; in another, 1' 52". 
 
 When fired at its maximum elevation of 28° 
 35', the time of loading — ^including depressing, 
 sponging, loading, elevating again, and running 
 into battery — varied from 8' 10" to 4'. 
 
 The shell is attached to an oaken sabot. In 
 loading, it is seized by nippers, the points of which 
 enter small holes in opposite extremities of a 
 diameter of the spherical surface. Four men, with 
 a handspike passed through a ring (of the nippers) 
 and standing on a platform about 4 feet below the 
 muzzle, easily raise it. When opposite the muzzle, 
 another man turns it on the axis of suspension, so 
 as to introduce the sabot into the bore. It is then 
 easily rammed home. 
 
 The weight of the shells used during the firing 
 made in presence of the board of officers varied 
 from 305 to 337 lbs. Captain Eodman proposes 
 
THE FIFTEEN-INCH GUN. 39 
 
 to make them of two classes. The first for use, 
 properly speaking, as a sliell^ may vary in weight 
 according to the particular purposes for which it 
 may be required. Where the greatest possible ex- 
 plosive effect is wanted, the shell could be of the 
 minimum thickness admissible (to endure the shock 
 of the charge), which, if supposed to be 2^ inches, 
 would make a shell of about 305 lbs. weight, con- 
 taining from 16 to 18 lbs. of powder. For batter- 
 ing, the shell would have a wall of 5 inches thick- 
 ness and weight of about 410 lbs. The windage is 
 1-1 0th inch, and a solid shot would weigh 425 lbs. 
 It is not deemed practicable to cast a satisfactory 
 solid shot of this diameter (for reasons already 
 mentioned connected with solid castings of large 
 masses), and it is believed a shell of this thickness 
 would present the maximum resistance to crushing, 
 while the loss of weight by its 5-inch cavity is but 
 trifling. 
 
 The most important results of the practice may 
 be briefly stated as follows : — In firing for accuracy 
 with the minimum charges mentioned, at a target 
 2,000 yards distant, with 6° elevation, the shot 
 struck the ground (about 8 feet below the level of 
 the gun) at (5 trials) 2,017, 1,937, 1,902, 1,892, 
 1,873 yards. The lateral deviations were, 1, 3, §, 
 5 yards to right and 5 yards to left, showing, at 
 
40 THE FIFTEE]Sr-rNCH GUN. 
 
 this range of 1-L miles, a very great accuracy as re- 
 gards horizontal deviations, to test wMcli the firings 
 were made. The vertical deviations were probably 
 due to varying initial velocities, or perhaps to 
 some difference in the weight of the shells fired. 
 Had the shot been intercepted at the target by a 
 vertical plane, they would have been found in- 
 cluded in a vertical extent of about 16 yards — 
 not much over the height of a three-decker. 
 
 The time of flight in these firings varied from 
 6^ to 7 seconds, giving an average velocity of about 
 900 feet per second. 
 
 By experiments made for determining the iii- 
 itial velocity, the average was 1,328 feet per second 
 with 40 lbs. of Zaw-^e-grained powder, and 1,282 
 feet per second with 50 lbs. of perforated cake 
 powder. 
 
 The Tcmges with maximum elevation of 28° 35', 
 — shells of 334 lbs. and 50 lbs. of Rodman's per- 
 forated cake powder, — were as follows, 5,298, 4,950, 
 5,375 yards. 
 
 With 40 lbs. large-grain powder, they were 
 5,435, 5,062, 5,730 yards, and the time of flight 
 about 27 seconds. 
 
 With 10° elevation, and 40 lbs. large-grain 
 powder, they were 2,700, 2,900, 2,754, 2,760 yards. 
 
 These ranges do not exhibit any decided ad- 
 
THE FIFTEEN-INCH GUN. 41 
 
 vantage of those obtained from the lO-inch gun 
 up to 10° elevation. Beyond that elevation the 
 gain is considerable, and may be estimated at about 
 600 yards for the elevation of 28° 35'. With 39° 
 elevation, and a charge of 40 lbs. large-grained 
 powder, it is probable a range considerably be- 
 yond 4 miles might be attained. Indeed, the 
 conviction appeared to be general among the offi- 
 cers who witnessed the firings, that the gun could, 
 if necessary, bear much heavier charges, though, for 
 all ordinary uses, it is doubtless best to keep them 
 down to somewhat less than the above. 
 
 Such charges produce far less strain on the gun 
 than would otherwise obtain, owing to the nature 
 of the powder used, and described above as " large- 
 " grained," and as " Rodman's perforated cake pow- 
 " der." The former differs from common powder 
 only in the size of the grains, which are 6- 10th 
 inch cube, and the degree of pressure to which it is 
 subjected in the manufacture. The latter is pre- 
 pared in solid compressed cakes (subjected to a 
 pressure in the making equal to what they will 
 be subjected to in the gun) and perforated with 
 holes to permit access to the flame. They are, I 
 believe, improvements and inventions of Captain 
 Rodman, and intended, by retarding the burning, 
 to reduce the excessive strain to which large guns 
 
42 THE FIFTEElSr-rNrCH GUN. 
 
 are subject witli fine-grained powders, wMch are in- 
 flamed almost instantaneously, and before the heavy 
 projectile is started from its seat. THs result is 
 shown by the "presstire gauge" attached to the 
 gun, or introduced into its chamber. The compara- 
 tive initial pressures of the "perforated cake," 
 " large-grained," and common cannon powder, are 
 estimated to have about the ratios of \, \, and 
 unity. This is a result of very great importance in 
 its bearing upon the practicability of using cast- 
 iron guns of extraordinary calibres. 
 
 But the question will doubtless suggest itself to 
 many readers, " of what use are such extraordinary 
 " calibres ?" " Are not rifled guns destined to su- 
 " percede aS smooth-bore guns; and do not the 
 " highest authorities ' express the conviction that 
 " ' such immense pieces of ordnance are quite in- 
 " ' applicable either for sea or land service ?' " * 
 
 In reference to rifle guns, it is doubtless true 
 that they are destined to play an important part 
 hereafter ; that they possess qualities of range and 
 accuracy which must make them, wliere these quali- 
 ties are of controlling impm'tance, supercede the 
 smooth-bore guns. Eange and accuracy are, how- 
 ever, of little value, unless the projectile possesses 
 the necessary destructive qualities. Rifle-guns do 
 
 " Vide Sir H. Douglas' "Naval Gunnery," page 1V4., 
 
THE FIFTEEN-IlSrCH GUN". 43 
 
 not prove to be the most effective for destroy- 
 ing masonry walls,* nor do they possess any de- 
 cided superiority over the solid-shot gun of but 
 8-inch calibre, when used against iron-plated ves- 
 sels.f Mr. Whitworth, indeed, forces one of his 68- 
 pound bolts (of but 3 inches diameter) through the 
 4^ inch thick plate of an iron-clad floating battery ; 
 but this can only be done at very short range, say 
 100 yards, — and a clean round hole of but three 
 inches diameter in a vessel's side is not a dangerous 
 affair. Sir Wm. Armstrong's gun is mainly in- 
 tended for shells, though it may be used as a solid- 
 shot gun. He admits, however, that the " expe- 
 " diency of using it as a solid-shot gun is doubtful," 
 and that " iron-plated vessels are practically secure 
 " against any shot he can send against them." For 
 short ranges the rifle gun possesses no very de- 
 cided , superiority over smooth bores, while the ex- 
 pense and trouble of using them is much greater. 
 They will, therefore, be mainly used in our sea-coast 
 batteries as a shell gun, and for long ranges upon 
 distant or approaching vessels. All oui- most im- 
 portant works should include a certain number of 
 
 * Ibid., page 236. 
 
 + " Experiments upon the Alfred showed but slight advantage in Whit- 
 " worth's weapon or projectile, over the solid 68-povinder, as an annihilator 
 " of iron plaites." — (Blackwood's Magazine, May and Nov., 1860.) 
 
44 THE FIFTEEPf-nfCH GUN. 
 
 these guns in their armaments, and it is pretty cer- 
 tain tliat we need not be behind any nation in 
 their consti"vu;tion. 
 
 To return to the question as to the use of such 
 extraordinary calibres. It might with ahnost equal 
 propriety be asked, "What is the use of rniy 
 " guns V Confining the answer to their uses in sea- 
 coast batteries, it would doubtless be, "To destroy or 
 " disable the enemy's ship or floating battery which 
 " should attempt to engage or to pass it." This 
 being the real and only object for which the bat- 
 tery is erected and the gun placed on it, there 
 should be no other limit to the calibre than the 
 perfect attainment of this object. For ships or float- 
 ing structures, the calibre is limited by considera- 
 tions of weight, &c., which need not be considered 
 in the shore battery. 
 
 " Unwieldiness " is doubtless an objection ; but 
 the reverse quality is not everything, and it is 
 better to be a half hour (if it were necessary) firing 
 one shot that does its business, than to expend the 
 same time in firing ten which do no harm. 
 
 The number of 24 and 32 pound shot which 
 timber ships have received in their side in naval 
 actions without being disabled would be incredible 
 if not authenticated, yet vast numbers of such guns 
 are at this day mounted in European sea-coast bat- 
 
THE FIFTEEN-INCH G-XJN. 45 
 
 teries. In face of all experience, sucli guns are ex- 
 pected to accomplisli their object of preventing the 
 passage of, or driving off, an enemy's fleet, — and 
 when they do not^ the cry is raised, that forts are of 
 no avail against fleets. In all the actions which we 
 read of in which ships have obtained apparent ad- 
 vantages over batteries, or have been able barely 
 to maintain an equal contest, they have had no 
 heavier calibres than these to contend with. Such 
 shot either fail to penetrate entirely the vessel's 
 side, or, at best, make a hole which almost closes, of 
 itseK, by the elasticity of the wooden fibres. Pos- 
 sessing little mass, immense velocity is necessary, — a 
 circumstance unfavorable to smasliing effect even 
 if their magnitude was sufficient. A leaden bullet 
 fired from a pistol will penetrate a pane of glass by 
 a clean round hole ; the same thrown by the hand 
 will smash it to fragments. To da/mage a vessel 
 seriously it is not the hole-puncturing property 
 which we need, it is the smashing effect — the stav- 
 ing in of planking and timbers ; or, if a hole alone 
 is made, that it shall be so large as to defy plug- 
 ging. Of course, it is the larger projectile qnl/y that 
 can make the large hole; and all experience (as 
 well as theory) tells us that, for smashing effects, 
 large masses with moderate velocities are the most 
 
46 THE FIFTEEN-mCH GVN. 
 
 efficient.* The remarkable effects produced by the 
 dilapidated and poorly-manned TurMsh batteries 
 on the Dardanelles, upon Admiral Duckforth's fleet, 
 in 1807 (fully related in my pamphlet on the 
 " Dangers and Defences of New York "), are suffi- 
 cient to prove that large-calibred guns are not only 
 not unmanageable, but the onk/ kind of gun proper 
 for sea-coast defence, for no other will produce, by a 
 siTiffle hit, such disastrous effects ; and a multitude 
 of nearly harmless hits are no equivalent, as expe- 
 rience of naval actions has so fully shown, for such 
 vital blows. Against wooden ships the shell is 
 doubtless the most effective missUe. We would in- 
 crease its range to the outside limit of actual solid- 
 shot range, and we would make it of such capacity 
 as to disable a vessel by a single explosion. For 
 this, too, we must have large calibres. 
 
 This is by no means a novel idea with American 
 engineers. From the very beginning of their labors 
 on sea-coast defences, they have demanded Ixj/rge 
 guns for their batteries. This demand has been 
 met by our Ordnance Department as rapidly as the 
 means have been perfected of manufactwing large- 
 calibred ordnance. 24-pounder and 32-pounder 
 guns have given way entirely to larger guns. The 
 
 ' Naval Gunnery, page 241. 
 
THE riFTEEN-rN-CH GUN. 47 
 
 42-poTinder (retained of late years only as a hot- 
 pot gun) will soon be discarded, when tlie arma- 
 ment of our important sea-coast batteries will 
 consist exclusively (until we add something still 
 larger) of 8 and 10 inch Columbiads, capable of 
 use as shell or shot guns, as occasion requires, — Iwt 
 shot being fired from the 8-inch gun. 
 
 "We believe these guns to be most formidable, 
 and that no fleet would attempt to pass an array 
 of batteries so armed without so imperious a mo- 
 tive as to justify the most severe losses ; and we 
 believe (since the degree of invulnerability that 
 can be given to a floating structure is necessarily 
 limited) that no floating battery that is, or will he 
 built, will successfully contend with our batteries 
 (whether they be of masonry or earth). But we 
 do not believe that we have yet attained the ex- 
 treme limit of calibre which sea-coast batteries re- 
 quire, or, rather, which may be advantageously used 
 in them. In the words of the Board of Officers 
 who witnessed the firings of the 15-inch gun at 
 Fort Monroe, and who unanimously recommended 
 (after certain further test firings) its adoption, 
 " There may be cases iu which it is of the utmost 
 " importance that a single missile shall be sufficient 
 " — ^if not to destroy — to entirely disable " the ves- 
 sel at Avhich it is directed. Such an effect can only 
 
48 THE FIFTEElSr-rNCH GUH". 
 
 be expected from a gun of " extraordinary " cali- 
 bre. The great facility with which the 15-inch 
 gun is wielded^ proves that its magnitude is not 
 inconsistent with efficient service. 
 
 The introduction of a new engine specially 
 adwpted to the attack of fortifications — I mean the 
 iron-clad floating battery — and the probability that 
 ships-of-war will soon be mostly clad in plates of 
 iron, invulnerable to ordinary solid shot, call for 
 some counteracting agent in the shore battery; 
 and that agent will most likely be found in the 
 use of projectUes of extraordinary calibre. Recent 
 writers on these subjects exult in the expectation 
 that iron-clad ships of war will soon supersede the 
 wooden, and that they will be so practically invul- 
 nerable that they "can engage at breaching dis- 
 " tance, with effect, any land battery." However 
 this may be, it is perfectly certain that Thereafter it 
 is not with ordinary fleets of wooden ships that 
 sea-coast batteries will be called upon to contend. 
 Such fleets may indeed attempt, for ulterior objects, 
 to jpass rapidly by such batteries, but if the object 
 is their reduction, as was the case at Algiers, at 
 Vera Cruz, at St. Jean d'Acre, at Sevastopol (naval 
 attack of Oct. 17, 1854), at Cronstadt (threatened 
 but not attempted), the attack will be made, not 
 with "Agamemnons," "Arethusas," and "Albions" 
 
THE FIFTEEN-INCH GUN. 49 
 
 — ^wooden coffins filled with sailors, to be burnt up or 
 blown up by modern incendiary and explosive mis- 
 siles, as was the Turkisli fleet at Sinope, " in fifteen 
 " minutes "*— but with vessels especially designed 
 for the purpose, viz. : the bomb-vessel and the iron- 
 clad floating battery,f and, probably, iron-clad ships 
 of war. 
 
 * At Sinope two TurMsli frigates were blown up in ffteen minutes by 
 the shell guns of the Russian fleet. In the contests which the allied fleets 
 had with Russian fortifications, the modern armament of shell guns of large 
 calibres does not appear to have existed ; and hot shot, if used at all, were 
 used very sparingly. Hence, those contests aflford no indication of what the 
 result would be of contests of wooden vessels against batteries armed with 
 large-oalibred shell guns, <fec. 
 
 f In ray pamphlet on the " Dangers and Defences of New York," I did 
 not hesitate to call the naval attack on Sevastopol (October 17, 1854) " the 
 " last attempt to array ships of the line and ordinary vessels of war against 
 " fortifications." The writer of " Iron-clad Ships of War," in Blackwood's 
 Magazine (November and December, 1860), uses identical language: — 
 
 " On the 17th October, 1854, the final experiment of wooden ships against 
 " granite and earthern walls was made, — never, we believe, again to be re- 
 " peated until iron-clad ships range up in line of battle." 
 
 He also gives a summary of the residts of that attack and of the taking of 
 Bomarsund, which I quote, for its confirmation of statements of mine else- 
 where made, and for reference hereafter : — 
 
 " The allied fleet was repulsed. The Agamemnon, the Albion, Sans- 
 "pareil, and other ships, did all that skill, gallantry, and daring could 
 " accomplish to silence that Fort Constantine. They did not succeed ; neither 
 " will the Russian official accounts acknowledge that any damage was in- 
 " flicted, other than injury to the guns and parapet of the crown of that 
 " fortress, where the cannon and men were exposed. To Bomarsund we 
 " need not allude, further than that it defied a huge allied fleet, but went 
 " down, like a fortress built of a pack of cards, when a small division of 
 7 
 
50 THE FUTEEN-INCH GITS. 
 
 It is well known that in tlie Kussian war iron- 
 clad floating batteries (the sides coated with wr ought- 
 iron plates, 4 or 4i- inches thick) were built by the 
 allies, for their intended operations against the Kus- 
 sian fortifications in the Baltic and Black Seas. The 
 only trial that was had of them was at Kinburn, 
 where three French floating batteries, in conjunction 
 with the enormous allied fleet, engaged (at about 
 800 yards distance) in the attack on that feeble 
 place.* The result was not unsatisfactory. One of 
 them was struck sixty-three times, with no material 
 damage. In short, these batteries may be considered 
 to have shown themselves shot-proof at iJiat distance 
 (800 yards), and against 2,%pou7ider shot. Not a 
 very decisive test, to be siu-e ; for, though so feeble 
 and dilapidated a work as Kinburn may be engaged 
 with effect at 800 yards, a well-arranged masonry 
 work, or earthen battery, must be engaged at 400, 
 or even 200, yards to produce any effect, whether 
 the intention be to batter, or to throw grape and 
 canister at the enemy's gunners ; and, instead of 32- 
 pounder shot, they must expect to be hammered at 
 
 " troops was directed upon It, and when our ship-guns, instead of being 
 " fought behind parapets of wood, were placed on shore, and the crews 
 " properly protected." 
 
 * An account of this affair is given in the pamplilet already alluded to, 
 entitled " Dangers and Defences," Ac. 
 
THE FIFTEEN-INCH GTJN. 51 
 
 by solid shot of not less than 8 inctes diameter, or 
 68 pounds weight. 
 
 Various experiments have been made in England 
 to test the resistance of these vessels— or of targets 
 constructed in like manner — to the Armstrong and 
 Whitworth projectiles, and to 68-pounder shot. Sir 
 H. Douglas records many of the results, in the recent 
 edition of his Naval Gunnery, and emits the opinion 
 that " no perfectly shot-proof ships, capable of resist- 
 " ing a protracted cannonade of 68-pounder solid- 
 " shot guns, and the new rifled guns, has yet been 
 " produced ;" and that " iron, whether cast or 
 " wrought, is the worst material, excepting steel, 
 " that can be used for strengthening either sea or 
 " land defences ;" and that " iron vessels are and will 
 " be found unfit for all purposes of war." 
 
 Per contra : able and professional writers in the 
 London Quarterly Review* and Blackwood's Maga- 
 zine hold the opposite opinion, and announce their 
 belief that " wooden walls " must give way to some- 
 thing which will exclude the feflrful missiles which 
 modern science has invented. These opinions are 
 shared by many of the ablest officers of the British 
 navy. 
 
 * The writer says of Sir Howard's opinions, " It is difBcnlt to see by 
 " what process of reasoning he arrives at this result." And Blackwood 
 says, " On all the many professional points involved in iron-clad ships, we 
 " cannot think him a safe or impartial guide," 
 
52 THE FiFTEEN-rNCH GUN. 
 
 It woiild be tedious to enter into tlie details of 
 tlie experiments made. In general terms it may be 
 stated that, with proper svpport lehind, dj-incli iron 
 plates are practically proof against shells, bot sbot, 
 and cast-iron sbot (notbing over 8 incbes bas been 
 tried, I believe) ; tbat tbey bave been penetrated 
 by wrought-iton 8-incb sbot at sbort ranges (say 
 200 yards — only, I bebeve, by successive bitting on 
 or near tbe same spot) ; and tbat Mr. Wbitwortb 
 bas forced one of bis flat-beaded wrougbt-iron pro- 
 jectiles tbrougb 4-incb plates, at 200 yards distance, 
 on tbe side of tbe floating battery " Trusty," and at 
 400 yards on tbe side of tbe frigate "Alfred." Tbe 
 conclusion arrived at by tbe advocates of this 
 metbod of construction is, tbat tbe sbip of war or 
 floating battery, properly huilt^ may be considered 
 practically safe against tbe projectiles I bave men- 
 tioned, beyond 200 yards. Assuredly, in tbis day, 
 wben many naval officers declare* tbat naval en- 
 
 * Sir Howard Douglas does not appear to be of this opinion. He thinks 
 that naval actions will be commenced and carried on at great distances, and 
 will "be conducted with the utmost circumspection, tactical skill, and prac- 
 "tical science." As the "final struggle and close quarters" must come at 
 last, however (at least when fleets are engaged), — and, as he admits, it is 
 " not always in the power of the commander of a ship, however desirous he 
 " may be of avoiding close action, to be able to accomplish that purpose," 
 — ^it is not very apparent how these predicted destructive effects will be 
 escaped. Certain it is that the successful introduction of iron-clad vessels 
 by one nation will compel their adoption by others who would not be driven 
 from the ocean. 
 
THE riFTEEN-riSrCH GJTN. 53 
 
 gagements between wooden vessels are like to be 
 Kilkeni^ cat-figMs, — wlien which shall go to the hot- 
 torn last (if time is wortb cov/ntmg wben the pro- 
 cess, for both parties, is so brief) is tbe main ques- 
 tion, — it is an immense step in tbe direction to 
 wMcb things must inevitably tend to have vessels 
 which can claim this degree (no small one) of invul- 
 nerability. 
 
 Acting npon such views, the French Emperor 
 has built an iron-clad ship of war — "Le Gloire" — 
 carrying 38 rifled 50-pounders, and is now building, 
 according to Blackwood, nine more, so as to have, 
 by next Spring, 300 rifled guns afloat in such vessels. 
 England is following suit, and in the ""Warrior," a 
 vessel 420 /i?e^ long, and of over 6,000 tons, is build- 
 ing a rival to " Le Gloire." 
 
 A new principle has, however, been introduced 
 in England, which is calculated to give a much 
 greater degree of invulnerability — that of inclining 
 the iron-clad sides inwardly (to an angle with the 
 horizontal of 35° or 40°) — by which arrangement 
 shot will glance off with little injury to the side.* 
 
 * If a projectile strikes a plane surface perpendicularly, its whole living 
 force {rotary velocity not being considered, as it is not very great in balls 
 from smooth-bore gnns) is available at the point of impact, either in pene- 
 trating or breaking through the surface. 
 
 If it impinges obliquely its velocity, A B, may be considered as decom- 
 
54 THE FIFTBEN-IU'CH GUK. 
 
 In addition to tHs, it is proposed to suppress tlie 
 port-lwles (certainly a very desiraUe stepjbowards 
 obtaining a satisfactory degree of invulnerability), 
 and to place the guns in rotating iron cwpolas (ac- 
 
 posed into two components, ITC and BC, the first of which only is avaUable 
 in rupturing the plane. If the angle, BAG, were 45° (ahmt the angle of 
 
 C 
 
 incidence for the proposed inclined ribs of ships of war), the living force (or 
 power of doing the vm-lc of smashing or penetrating) due to the component, 
 A C, is just half of that due to the entire Telocity of the projectile, A B. 
 Thus, by this simple arrangement, the projectile is at once disarmed of half 
 its destructive powers. But this is not all: the projectile will not coKcen- 
 trate all the effect due to the component, A C, at the point A, as it would if 
 A C were the <yidy velocity with which it arrived. By the component, B C, 
 it will be carried along towards D, simultaneously with the actioij of A C, 
 upon the plane. For want of concentration upon a single point, the penetrat- 
 ing power of the component, A C, may be considered as (within certain 
 limits) wholly lost ; the entire living force due it is, nevertheless, wholly 
 expended upon the bulwark, E D (provided it does not escape at the point 
 X>, before the reflection is complete) ; but it is likely that the smashing power 
 (i. e., of breaking dovm the bulwark) is much diminished (owing to its dis- 
 tribution over considerable space\ In short, with an angle of incidence of 
 45° the power of penetration of the ball would be wholly lost ; that of smash- 
 ing the bulwark reduced to considerable below one half. If, therefore, we 
 throw at these inclined sides a projectile of such magnitude that its living 
 
THE FIlT^EEW-riSrCH GTTK. 55 
 
 cording to an invention of Captain Cowper Coles, E. 
 N.), from whicli, by a rotary of 180°, they fire over 
 tlie bulwarks on either broadside, — the gunners 
 being perfectly sheltered under these shot-proof 
 covers. 
 
 Grave objections to such an arrangement of 
 guns, particularly in an unstable and rolling struc- 
 ture, readily suggest themselves. It would not do, 
 however, for a landsman — ^probably not for a sea- 
 man — ^to pass judgment upon it before thorough 
 trial has been made. It is probably worth that 
 trial, and, if not found successful, may lead to some- 
 thing of the kind which will be. 
 
 A vessel arranged according to these ideas,* 
 having the length and beam of a three-decker, would 
 carry but 14 guns (available on either broadside). 
 But it is contended, with much justice, I think, 
 that such a vessel, almost invulnerable to anything 
 carried afloat, to such sea-coast artillery as European 
 works are armed with, is a far more formidable 
 
 force is considerably more than double — say four times — that -which experi- 
 ence shows sufBcient to break down a vertical bulwark, we may expect to 
 accomplish the object. At any rate, we can do it without going beyond the 
 limits of practical ma^'nitude in projectiles. 
 
 Experiments at Metz, in 18S4, showed that masonry walls could be 
 breached at an angle of 25° or 30° with (I suppose) ordinary breaching 
 artillery, viz.: 18 or 24 pounders. 
 
 * For a full description of the proposed vessel, and a discussion of the 
 subject generally, see the interesting papers in November and December 
 numbers of Blackwood s Magazine. 
 
56 THE FIITEEW-IKCH GXTW. 
 
 vessel than tlie vulneraUe, fragile, and coml)ustible 
 100-gun three-decker, incapable of approacMng a 
 fortification or of engaging an enemy, except at long 
 range, without the strong probability of being 
 blown up, or sent at once to the bottom, and in 
 imminent danger even from the accumulation of 
 powder and shells for so many guns in so limited a 
 space ; while her reduced crew (250 against 1,000) 
 would soon compensate for her enhanced cost, and 
 relieve the question of finding men for ships of war 
 of much of its difficulty. 
 
 In devising our sea-coast armament, all these 
 facts, all the established improvements in military 
 and naval art, and all clearly-seen tendencies towa/rds 
 progress and change, must be considered. The rifted 
 gun, from its great accuracy and penetrating power, 
 and more especially for its power of throwing a 
 loaded shell with an accuracy and range beyond 
 what have heretofore been considered to belong to 
 solid-shot guns, is a very important gun to sea-coast 
 batteries. Its most important use, however, will be 
 as an incendiary and explosive agent against wooden 
 vessels at long ranges. Its principle has not yet 
 been successfully applied to large calibres,* and it 
 is not likely it wUl be, not only because of their 
 
 * The largest Armstrong gun is the 80-pounder, of which the calibre is 
 seyen inches. It has been fired with a 100-pound projectile. Whitworth's 
 68-pound holt is fired from a gun of but three inches in calibre. 
 
THE FIFTEEISr-riirCH GUN. 57 
 
 much, greater expense and difficulty of construction, 
 but because the peculiar advantages of the rifled 
 over the smooth-bore gun diminisli witli the calibre.* 
 They are not (as I have remarked before) a formi- 
 dable projectile against iron-clad ships. The 3-inch 
 hole which Mr. Whitworth makes by firing a 
 wrought-iron holt at 100 or 200 yards is not a 
 serious injury, and can only be made at distances 
 less than we should be permitted to count upon. 
 It is not to hore a hole\ through these iron plates, 
 but to smash the sides of the vessel that carries 
 them, ■ that we have to do. They are practically 
 proof against Armstrong's guns. 68-pdr. wrought- 
 iron shot from an 8-inch columbiad would, by dint 
 of hammering, at 200 or 300 yards, succeed in 
 breaking out pieces of vertical-sided vessels. This 
 effect is quite inadequate, though, even against such 
 vessels. Against the inclined-sided vessel even our 
 solid cast-iron 10-inch shot would probably glance 
 off without doing such serious damage as we desire. 
 
 * Vide Thomas' work on " Kifled Ordnance." 
 
 f It has been suggested that the iron-clad vessel may be penetrated by 
 the Whitworth bolt helow water, and sunk. Of this contingency the Black- 
 wood writer discourses as follows : — " ' A chance shot,' as the American one- 
 " gun privateer observed to the captain of a 50-gun frigate, ' may knock the 
 " ' devil's horns off ; ' and a chance Whitworth may have passed through 
 " thirty feet of water and penetrated a wooden bottom; but to make direct 
 " practice, his gun must be within twenty feet of his opponent." 
 
58 THE FIFTEEN-nsrcn GUW. 
 
 We have notMng, therefore, wMch will tliorougHy 
 and completely accomplisli tlie object for wHcli our 
 battery is built. We liave gone to enormous expense 
 in works to protect our cities and harbors, and find 
 that the instrument, of which the work is but the 
 emplacement, is inadequate. We have got our " mon- 
 " ster," and find, if not " toothless," at least its teeth 
 are only fit to masticate flesh, and they are given 
 nuts to crack. It is sheer nonsense to talk about 
 " unwieldiness " in such a case. The gun that will 
 do the business required of it must be wielded, 
 whether it is found to be a 15 or a 20 inch, or even 
 a thirty inch, gun.* 
 
 When these iron-clad ships come to " engage, at 
 
 * The writer (M. Delamarre) of a series of articles in one of the Paris 
 journals, entitled "Les ports maritimes et I'artillerie moderne," of which the 
 principal object is to point out the measures rendered necessary, by im- 
 provements in modem artillery, for the security of the sea-ports of France, 
 uses the following language in speaHng of Brest : — 
 
 "L'entrfie du goulet de Brest a, 6%& jusqv,' (2 ^reseref fortement d6fendue 
 "par 270 benches a feu, qui eussent assurgment coul6 un capitaine ennemmi 
 " assez audacieux pour tenter de forcer le passage. Elle pent etre encore 
 "mieux d^fendue au moyen de canons d'un Inorme calibre, et d'autres ap- 
 " pareils qui ecraseraient infaUliblement les plus solides vaisseaux blindfe, 
 " frappds k bout portant." (" The entrance to the port of Brest has been 
 " hitherto defended by 270 guns, which would assuredly have sunk the ene- 
 " my bold enough to attempt to force the passage. It can be still better 
 " defended by means of cannon of enormom calibre, and other contrivances, 
 " which would infallible/ crush the strongest iron-clad vessels at point-blank 
 " range.") (The italics are mine.) 
 
THE MFTEEN-nsrCH GVN. 59 
 
 " breaching distance, our eartli or stone forts," and 
 to have their " laugh "* at them, we do not try to 
 punch holes in them ; we wish to stave in the whole 
 
 * The writer of the articles already referred to in BlackwooeCs Magazine 
 thinks that " before another twelTemonth every sensible person in this 
 " country will see the folly of erecting forts of stone or earth for iron-clad 
 " vessels to laugh at " Not so fast, my dear sir. Festina lente is yet a good 
 maxim, as well in forming conclusions as in substituting new methods and 
 constructions for old. Do the best you can to make your floating structure 
 shot-proof, and they cannot endure the protracted battering which they 
 m«si endure if they would " engage at breaching distance " a, properly-built 
 and properly-armed stone or earthen fort. The subject will be referred to 
 in what I propose to say about casemate embrasures. Admitting, for the 
 sake of argument, however, that there is any reason for believing that well- 
 built masonry batteries may be breached by guns in iron-clad vessels, it is 
 easy to turn the balance the other way by resorting to the same means for 
 procuring invulnerability that the floating battery does, viz., iron plates. 
 In this kind of contest (for invulnerability) all the advantage is on the side 
 of the shore battery. " The idea that a floating structure can be made shot- 
 " proof while the walls of a fort cannot, is so transparently absurd as 
 " scarcely to require refutation." — (Dangers and Defences.) And with all 
 due deference to Sir Howard Douglas, masonry will form the mass — iron, 
 the external protection — of such a battery. The stone fort, therefore (indis- 
 pensably necessary in many cases for want of sif^^s suitable for anything 
 else), will require but the addition of the iron sheathing to give it the re 
 quired degree of invulnerability. To make it wholly of iron would be a 
 pure waste of money. General Totten, after elaborate experiments, has 
 used the following language : — " Were it not for the vastly greater cost, the 
 " whole scarp might be faced with iron — ^indeed, might be made of iron 
 " only ; but, until there shaU be much stronger reasons than now exist, or 
 " are now anticipated, for believing that well-constructed masonry batteries 
 " may be breached by naval broadsides, the cheaper construction may be 
 " safely followed, especially as, should such a necessity ever arise, they may 
 " be externally plated with iron." 
 
60 THE riFTEEH--I]SrCH GTTN. 
 
 side. For tMs purpose masses of la/rge diainet&r 
 moving with moderate velocity are indispensable. 
 The 15-inch shell would probably be effectual 
 against the inclined-sided battery, and would be 
 likely to convert Captain Cole's cupolas into shoot- 
 ing-caps indeed. Penetrating and exploding in an 
 iron-clad or wooden vessel, a single one would 
 probably suffice. The inclined side of these newly- 
 13roposed ships would not, perhaps, be easily pene- 
 trated (though the side would, doubtless, be stove), 
 even by such a shell. But it must be recollected 
 that about one-half of such a ship is not invulnera- 
 ble — the citadel, or protected portion, occupying 
 only the midships — and the effect of such an ex- 
 plosion in the bow or stem would tell fearfully upon 
 the ship, and upon such of the crew as were not 
 in the " citadel." 
 
 Fifteen inches is the calibre of the gun made as 
 an experiment to test the practicability of casting 
 guns of extraordinary calibre, and their efficiency. 
 The result has convinced our Ordnance officers that 
 it is not an extreme limit. A 20-inch gun can 
 probably be made, and not only made, but used 
 with facility and efficiency. Enormous and expen- 
 sive as they are, such guns may have their " mis- 
 " sion," and a few of them in our important sea- 
 coast batteries vdll probably be hereafter deemed 
 an essential part of their armament. 
 
CASEMATE EMBRASURES. 
 
Casemate Embrasures. 
 
 GtTBTS intended for sea-coast defence may be 
 arranged to fire over an earthen parapet, in wMcIl 
 case they are uncovered and without protection from 
 ricochet or vertical fire ; or they may be placed in 
 " casemates," — i. e., under bomb-proof vaults, behind 
 the masonry wall of a fortification. Each mode has 
 its own particular advantages and disadvantages, to 
 which I may refer hereafter : at present it is enough 
 to say that the choice is not always optional, and 
 that every nation that has defended its coasts at all 
 has found, it necessary to make use of casemated 
 batteries. 
 
 The placing of a gun " in casemate " involves the 
 necessity of some kind of an opening in the masonry 
 wall in front of it, that the gun may fire through, 
 which opening is called an " embrasure." This 
 opening must not only permit the gun to fire 
 through, but it must permit a horizontal latitude of 
 direction as great as possible. At the same time 
 
64 CASEMATE EMBEASTJRES. 
 
 that tMs horizontal latitude of fire, or " traverse " of 
 the gun, should be a maximum, the greater it is the 
 greater must be the cavity cut out of the wall to 
 allow it ; and it is evident that the larger the cavity- 
 cut out, the more it weakens the wall, and the more 
 of the enemy's missiles it will receive. 
 
 " The great importance of keeping the area of 
 " the outside openings of casemate embrasures at a 
 " minimum will clearly appear from our experiments. 
 " Fii'st, the number of the enemy's missiles passing 
 " through the opening will, of course, increase with 
 " the enlargement of that area ; and, secondly, what- 
 " ever may be the peculiar form of any embrasure, 
 " there must be a margin, larger as the opening is 
 " larger, where the walls, being materially weaker 
 " than elsewhere, will suffer the more from battering 
 " guns."* 
 
 The magnitude of the hole cut out of the wall, 
 as well as the area of the external opening, will 
 depend not only upon the degree of " traverse " 
 given to the gun, combined with the thickness of 
 the waU, but upon the position of the centre of 
 motion of the carriage. 
 
 European engineers have in general acted as if 
 they regarded the magnitude of the opening of little 
 
 * Vidi General Totten's Report on " Casemate Embrasures." 
 
CASEMATE EMBEASUEES. 65 
 
 consequence. Taking the center of motion within 
 Hie inner face of tlie wall, they have necessarily- 
 given the embrasure a " flare," or outward spread, 
 through the whole thickness. As a necessary con- 
 sequence, the exterior opening is immense, even 
 while the traverse of the gun is limited to but 30°. 
 
 American engineers, impressed with the import- 
 ance of the matter, have never — even in the earliest 
 
 # 
 
 of their works — constructed embrasures of the enor- 
 mous size now seen in European works of recent 
 date. The form of embrasure, however, which 
 was adopted, and is now found in nearly all our 
 constructions up to 1852, was designed by General 
 Jos. G. Totten, who describes it, and the manner in 
 which he was led to the design, as follows : — 
 
 "In 1815, the author of this report* was called 
 " on to prepare a project for the defence of an im- 
 " portant channel ; and, having been convinced, 
 " while employed as an assistant in the construction 
 " of two of the batteries just mentioned, that the 
 " principles and the details by which the embrasures 
 " and the dependent casemates had thus far been 
 " regulated were erroneous and defective, set about 
 " a careful study of the conditions to be fulfilled in 
 " providing for the heavy guns of that period, 
 " mounted on a casemate carriage, that had already 
 
 * On " Casemate Embraenres." 
 
66 
 
 CASEMATE EMBEASUBES. 
 
 Pig.l. 
 
 been proved and adopted. The result was an 
 
 embrasure Wing an exterior opening of 4 feet 
 
 wide by 2' 6" high at the 
 
 outside line of the cheeks, 
 
 and 3 feet high at the key 
 
 of the covering arch, — ^the 
 
 throat being 1' 10" wide. 
 
 This provided for all the 
 
 depression and elevation 
 
 of the gun that the carriage permitted, and also 
 
 for a horizontal scope of fall 60 degrees. Covered 
 
 with a lintel, instead of an arch, the height of the 
 
 exterior opening might be a little less than 3 
 
 feet." 
 
 "The plan of this embrasure shows that the 
 interior opening is 5' 6" wide, and that the plane 
 of the throat is within 2 feet of the outside of the 
 waU." 
 
 Fig. 2. 
 
 This form gives the maximum strength (with a 
 given thickness of wall) that it is possible to give 
 
CASEMATE EMBEA8UEES. 67 
 
 a pure masonry embrasure. The gradual increase 
 in the calibre of guns — ^the necessity of resisting the 
 shock q^ heavier projectiles than those formerly in 
 use — suggested to General Totten the necessity of an 
 increased thickness of wall, and an arrangement 
 combining other materials than masonry, by which 
 greater strength could be combined with the mini- 
 mum opening, and prompted t]|B course of experi- 
 ments which are described in the Report to the 
 Secretary of War on " Casemate Embrasures." 
 To use his own language : — 
 " The principal objects of the experiments were — 
 " 1st. To ascertain the effects of firing with solid 
 ' balls, with shells, and with grape and canister, 
 ' from heavy ordnance at short distances, upon 
 ' various materials used in the- construction of case- 
 ' mate embrasures." 
 
 " 2d. To determine whether these embrasures 
 ' might have a form that would shut out most of 
 ' these missiles, and resist, for a time, the heaviest, 
 ' without lessening the sector of fire, horizontal and 
 ' vertical, of the casemate-gun." 
 
 " 3d. To determine the degree to which, without 
 injury from the blast of the gun, or lessening its 
 ' scope of fire, the throat of the embrasure and also 
 the exterior opening might be lessened. 
 " 4th. To determine whether all smaller miss iles 
 
68 CASEMATE EMBKASUEES. 
 
 " miglit not be prevented from passing throngli the 
 " tkroat into tlie battery, and whetlier tlie smoke of 
 " the blast of tlie gun miglit not also be Iscluded 
 " by simple and easily-managed shutters." 
 
 The results of these experiments were considered 
 by General Totten " of great importance to the 
 " defensive system of the country." It is not likely 
 that he believed th% vs^ould be considered important 
 to the defensive systems of other countries, for Eu- 
 ropean engineers have not been in the habit of 
 looking in this direction for information, or for 
 precedents. That the experiments should have been 
 noticed by Sir Howard Douglas, in his " Naval 
 " Gunnery," was probably not expected ; but, if 
 noticed, it certainly was expected that it would be 
 in a manner indicating that that distinguished writer 
 and high authority had attentively read and per- 
 fectly understood the work he considered important 
 enough to notice. That he has done neither is not 
 very difficult to prove. 
 
 That he has not attentively read the report of 
 General Totten on " Casemate Embrasures," which 
 he reviews, there are numerous evidences. In stating 
 the " objects " for which the experiments were made 
 (just quoted by me) he extracts verbatim from the 
 text until he comes to the 4th, which he vrrites in 
 this way : — " To determine whether all smaller mis- 
 
CASEMATE EMBRASUEES. 69 
 
 " siles miglit not be prevented from passing through 
 " the throat into the battery hy shutters, consisting 
 " of two leaves of hoiler-iron, \ inch fhic\ hinged 
 " to vertical throat-irons, <fec." (the words in italics 
 being Sir Howard's own reading of the matter). 
 General Totten's own words are, " by simple and 
 " easily-managed shutters," — ^the thickness and man- 
 ner of construction being matters to be determined. 
 The conclusion arrived at is afterwards distinctly 
 stated by him. " A thickness of two inches is ample 
 " for shutters designed to stop the largest grape- 
 shot." And this two inches thickness is to be of 
 solid wrought iron. 
 
 After quoting some of the results of the firings. 
 Sir H. Douglas says, " It must have been from 
 " doubts such as these, of the efficiency of the expe- 
 " dient and the cost of executing General Totten's 
 " proposition, that the War Department declined to 
 " carry it into effect, in the following terms ;" and 
 the " following terms " are the words, verhatiwi et 
 literatim, of two paragraphs of my pamphlet on the 
 Dangers and Defences of New York (page 39), the 
 first being a quotation from the very work of General 
 Totten which Sir Howard is reviewing ; the second, 
 a comment of iny own ; the purport of the two being 
 simply that the whole scarp of a masomy battery, as 
 well as the embrasure, may be rendered invulnerable 
 
70 CASEMATE EMBRASURES. 
 
 by iron plates. The strange and utterly inconceiv- 
 aUe sense given to these paragraphs by Sir Howard 
 is puzzling enough, standing by itself. But if he 
 had attentively read the work before him (a Report 
 addressed to the Secretary of War) he would have 
 found the following paragraphs, in which the sanc- 
 tion of the War Department is expressly affirmed, 
 and which would have saved him from so absurd a 
 misapplication of the language of another : — 
 
 " The embrasure applied, since these experiments, 
 " to our casemated batteries, and which may be 
 " called the embrasure of 1855, devised in accord- 
 " ance with these deductions, and of which a model 
 " received yowr approval^ is believed to satisfy com- 
 " pletely all important conditions." (Italics my 
 own.) 
 
 " The greatly augmented strength and efficiency 
 " thus imparted to our system of national defence 
 " will be due to the enlightened and liberal forecast 
 " which prompted you, as Secretary of War, to 
 " sanction and sustain the course of experiments of 
 " which this report is the record." 
 
 Sir H. Douglas remarks, " Well do the distin- 
 " guished military enguieers of the United States 
 " see the absolute necessity of endeavoring to remedy 
 " the serious defects of their masonry defences, which 
 " their older brethren of 1808 introduced fifty-two 
 
CASEMATE EMBEASTJRES. 7l 
 
 " years ago, by strengthening tte throats of the 
 " embrasures with enormous slabs of iron." 
 
 There is no embrasure in existence in the United 
 States which dates back to 1808 ; very few indeed 
 farther than 1815. The embrasures which have 
 been made since that date " in all our casemated 
 " batteries " are described, in language already 
 quoted by me, as the design of General ToUen him- 
 self, who states that they " have, since 1815, been 
 " constructed, in all our casemated batteries, accord- 
 " ing to the preceding description ;"* and the 
 reasons why an " increase of strength " had become 
 necessary are gtated by him, in the Keport Sii- 
 Howard was reviewing, as follows : — 
 
 " This being the state of things with these em- 
 " brasures of 1815, an increase in their strength had, 
 " within a brief period, become expedient, not to 
 " say necessary, by the augmented calibres in ships' 
 " armaments." 
 
 The particular " form " had nothing to do with 
 these reasons (for the wrought iron throat-plate is 
 resorted to in the new embrasures because a new 
 form, better calculated to exclude missiles, is intro- 
 duced) ; but it was (as explained in par. 219), 
 whether the " thickness of scarp," which had been 
 " found sufficient to resist 24 and 32 pounder shot, 
 
 * Tiek " Casemate Embrasures," Tf 246, p. 166. 
 
72 CASEMATE EMBEASUEES. 
 
 " was now sufficient, with the growing calibres of 
 " naval armaments." More tlian 500 embrasures 
 have, since 1855, been constructed in the United 
 States according to the new model. 
 
 The foregoing remarks will illustrate the " care- 
 " fill perusal " of the work noticed by Sir Howard. 
 That he has not perfectly understood the work upon 
 which he so freely passes judgment, is perfectly evi- 
 dent from the whole tenor of his remarks. These 
 experiments, which were made at two different 
 periods, on ten different embrasures, — some of one 
 material, some of another ; some with iron shutters 
 or iron throat-plates, some without (the particular 
 arrangement differing in every case), — ^were made to 
 determine the best material, the best form, and the 
 exact arrangement, degree of strength, and maimer 
 of construction of the wrought iron throat-plates and 
 shutters intended to be used. Sir Howard treats 
 them as if they were experiments made upon the 
 new American embrasure, instead of the trial experi- 
 ments, by aid of which it was devised. Under no 
 other point of view could he quote these results as 
 he does, as results applying to our system, or use 
 language like the following : — 
 
 "To strengthen the throats, cheeks, and outer 
 " edges of the casemate embrasure, masses of 
 " wrought iron, 8 inches thick, composed of sixteen 
 
CASEMATE EMBEASTJEES. 73 
 
 " plates, each i in. thick, firmly welded together, 
 " backed by slais of cast iron, forming a frame on 
 " the sides, sole, and top of the throat, are firmly 
 " bonded into the masonry, — the cheeks notched in 
 " planes parallel to the face of the wall, or covered 
 " with wrought iron plates." (Italics my own.) 
 
 General Totten says ; — 
 
 " Our experiments show that wrought iron is 
 " the best material for insertion, as above mentioned, 
 " and that a thickness of 8 inches of wrought iron, 
 " solidly bached with masonry, will resist an 8-inch 
 " solid ball, fired with lOf pounds of powder, from 
 " a distance of 200 yards." (Italics my own.) 
 
 And, with reference to cast iron, he says : — 
 
 " The brittleness of cast iron unfits it for use as 
 " a means of directly resisting the shock of cannon- 
 " balls. This has long been well known. It was 
 " considered, however, worth while to try whether 
 " its cohesive strength might not be profited of by 
 " diffusing the shock of a ball over a considerable 
 " surface of this material through the intermedium 
 " of a thick plate of wrought iron. The compound 
 " plate of wrought iron interposed in the trials was 
 " made up of eight half-inch plates, solidly riveted 
 " together ; and a very even and uniform bearing of 
 " this 4-inch compound plate upon the cast iron was 
 " secured, — as perfect, certainly, as could be effected 
 
74 
 
 CASEMATE EMBEASTJEES. 
 
 " in general practice ; nevertlieless, the cast iron 
 " block was always broken, splintered, or badly 
 " cracked, by a ball striking tbe wrougM iron plate 
 " in front of it." 
 
 That General Totten's " conclusions " as to the 
 use of AVTOught iron may be fairly known, I repeat 
 them here : — 
 
 " Some important conclusions may be drawn 
 " from the results with wrought iron." 
 
 " First. It may be fairly assumed that a plate 
 " 8 inches thick, of wrought iron of good quality, 
 " kept in place by a backing of three feet of strong 
 " masonry, will stop a solid ball from an 8-inch 
 " Columbiad, fired with lOi lbs. of powder, from 
 " the distance of 200 yards. The plate of iron 
 " will be deeply indented at the point of impact, 
 " the ball carving for itself a smooth bed, of the 
 " shape and size nearly of one hemisphere, in which 
 " it win be foimd broken into many pieces, easily 
 " separable ; and it will, besides, be somewhat bent, 
 " generally. The masonry behind will be much 
 "jarred, and, unless strongly bonded, be consider- 
 " ably displaced ; moreover, unless the thickness 
 " of three feet is well tied into thicker masses 
 " immediately adjacent on the sides, and above, 
 " and below, the general damage will be severe." 
 " Second. This plate will be much the stronger 
 
• CASEMATE EMBEASIJEES. 75 
 
 " for being in a single mass, and not made up 
 " of several thinner plates. The continuity effected 
 " by bolts and rivets of tlie made-up plates is 
 " broken, even by weak assaults ; so that afterward 
 " the stronger, instead of a joint opposition, finds 
 " only a succession of feeble resistances." 
 
 " Third. A thickness of two inches is ample 
 " for shutters designed to stop the largest grape- 
 " shot. With this thickness they Avill be neither 
 " perforated nor deformed by anything less than 
 " cannon-balls or shells. These shutters, also, for 
 " the reasons just given, should be made of a 
 " single thickness. The firings show the necessity 
 " of concealing entirely, even from the smallest 
 " iron missile, their hinges and fastenings." 
 
 " Fourth. A wrought iron plate of half an inch 
 " in thickness is adequate to protect the outer mar- 
 " gins and the offsets of embrasures from injury 
 " by grape or canister shot." 
 
 Those who read Sir Howard's chapter on " Iron 
 Slabs combined with Masonry" doubtless suppose 
 (for his language leaves no room to suspect the 
 contrary) that he is actually describing the Amer- 
 ican embrasure, and that the experiments he de- 
 scribes refer to it. General Totten has given, 
 indeed, certain conclusions, but how he ^ has em- 
 bodied those conclusions into an embrasure he 
 
76 CASEMATE EMBRASUEES. 
 
 has not stated. It is most evident, from the oppo- 
 sition I have shown between his own language and 
 the descriptions and remarks of Sir Howard, that 
 the latter has not the slightest idea of wliat the 
 new-modeled embrasv/re really is; yet he boldly 
 pronounces judgment, as follows : — 
 
 " A careful perusal of General Totten's work, 
 " and an attentive examination of the results of 
 " the experiments carried on to test the efficacy 
 " of the expedient proposed by him, have left on 
 " the author's mind two very deep impressions — 
 " he might say, convictions : first, as to the inability 
 " of masonry walls ia general to resist the impacts 
 " of solid shot of large calibre; and, secondly, as 
 " to the defects of all masonry defences, and to the 
 " form proposed to be given by General Totten to 
 " the casemate embrasures of his system in pa/r- 
 " ticular." (Italics my own.) 
 
 General Totten, after a long life spent in the 
 active exercise of his profession, has probably a 
 greater experience in designing and constructing, 
 and a more universal acquaintance with the ex- 
 amples, here and abroad, of sea-coast fortifications, 
 than any man living ; and, an engineer by profession, 
 with fifty years of incessant practice, his opinions 
 as to the strength of materials and their capability 
 of resistmg the impact of projectiles necessarily 
 
CASEMATE EMBEASUEES. 
 
 77 
 
 Carry mucli weigM, — enougli to have justified Sir 
 Howard in withholding his judgment upon "his 
 system" until he knew what it was. 
 
 The form of the American embrasure appears to 
 he the object of Sir Howard's particular animadver- 
 sion. " In the United States embrasure," he says, 
 " the throat is placed within two feet of the wall,* 
 " and, consequently, the width of the parapet out- 
 " wards is reduced to two fifths of the thickness of 
 " the waU." 
 
 The propriety of the " consequently " is not very 
 apparent. There is about the throat of every em- 
 brasure ever yet designed (not strengthened by iron) 
 a weak portion, more easily broken than elsewhere. 
 This is an evil not peculiar to the old American 
 embrasure ; on the contrary, it is easily shown that 
 its form is that best adapted to strength. 
 
 * Within two feet of the outer face of the wall, we will presume Sir 
 Howard to mean. 
 
78 
 
 CASEMATE EMBEASUEES. 
 
 Kg. 4. 
 
 Fig. 3 represents tlie horizontal section of an 
 embrasure of a common European model. 
 
 Fig. 4, that of tlie American embrasure, having 
 its throat f the thickness of the wall from the 
 exterior face, both having a " flare," or allowing a 
 traverse to the gun of 30°. 
 
 Does it require any demonstration to prove 
 which is the weakest ? The angle A B O, in the 
 American embrasure, would be an oltuse angle of 
 150° ; the angle A B O oi the European model 
 would be an acute one of 75°. A shot striking the 
 flaring cheek of the second (as represented in the 
 figure) would be likely to break off the acute solid 
 angle a B c, along the line of fracture a c, carry- 
 ing away a large mass of masonry, and very much 
 enlarging the throat ; while a shot striking the 
 cheek A B of the other would be less likely to 
 
CASEMATE EMBKASTJEES.' 79 
 
 break away the angle, and, in doing so, would carry- 
 away mucli less masonry, and, consequently, cause 
 less enlargement of the throat. What a misuse of 
 words — what mere random talk — it is to say that 
 " the parapet outwards is reduced to two fifths the 
 " total thickness of the wall ! " 
 
 Not only has the old American model the supe- 
 riority just described, but it has another of great 
 importance. With the same width of throat, E B, 
 the exterior opening, A Z>, is much greater in the 
 European than in the American ;* and, as our ex- 
 periments have shown (even with a flare double 
 what is represented, in the figure) that nearly all 
 small missiles, and fragments of larger ones, which 
 strike the flaring sufaces, A S, are reflected so as to 
 pass through the throat, the American embrasure 
 affords vastly greater security to the gunners — -first, 
 because the throat is not so easily broken in ; second, 
 because the enemy's small missiles and fragments of 
 broken shot are more effectually intercepted. So 
 superior is this form that, instead of confining the 
 flare of the cheeks (as I have represented in the 
 figure, for the sake of making a just comparison 
 with the European) to 30°, we have made it 60°, as 
 
 * Emtrasures of recent European works present an opening of 50 or 
 more square feet. That of the old model American about 12; of the new 
 model (measured by the throat), 3.9 square feet. 
 
80 CASEMATE EMBEASUEES. 
 
 represented on page 66, thereby doubling tlie 
 traverse of the gun, — an effect, in most cases, equal 
 to doubling the nwmher of guns. Did, then. Sir 
 Howard Douglas understand at all what he was 
 writing about, when . he compliments us American 
 engineers of the present day with seeing the " abso- 
 " lute necessity of endeavoring to remedy the 
 " serious defects of those masonry defences which 
 " their elder brethren of 1808 introduced, fifty-two 
 " years ago, by strengthening the throats of the 
 " embrasures with enormous slabs of iron " ? 
 
 General Totten states distinctly his objects. So 
 far as the strength of the embrasure was concerned, 
 the form was not involved at all. He was aware 
 that we had the strongest form that could be made 
 of mason/ry / but it was desirable to know whether 
 a wall ^ve feet thick — ^thick enough to resist 24, 32, 
 or even 42 pounder shot — was still sufficient against 
 the " larger calibres " introduced into ships' arma- 
 ments. So far as form was the object of the ex- 
 periments, it is distinctly stated that they were to 
 " ascertain the effects of firing with solid balls, with 
 " shells, and with grape and canister, from heavy 
 " ordnance at short distances, upon various ma- 
 " terials used in the construction of casemate em- 
 " brasures," and thereby to ascertain what form 
 wotdd best exclude such missiles, and what ma- 
 terials were best adapted to that form. 
 
CASEMATE EMBEASUEES. 81 
 
 His life-long study of this and kindred subjects 
 had given Mm " dlep convictions " as to the part 
 wMcli sea-coast batteries, masonry or earth, had to 
 play — as to the peculiar tests they would be sub- 
 jected to. He had no fear as to the capability of 
 masonry walls to resist the cannonade of ships, so 
 long as they could keep it up, against the severe 
 retaliation to which they would themselves be 
 exposed. Against " increased calibres," some thick- 
 ening of walls might be necessary — nothing more. 
 He knew that the real danger of casemated bat- 
 teries (a danger to which, however, earthen bat- 
 teries on low sites, with deep water near them, are 
 tenfold more exposed) was, that ships should lay 
 themselves close alongside and pour canister or 
 grape into the embrasures, — ^their superior number 
 of guns giving them a great advantage in this kind 
 of contest, — unless the funnel-shaped openings 
 (already greatly reduced from European models) 
 could be modified so as to further reduce it to the 
 minimum required for the muzzle of the gun. 
 
 The result of these experiments was, that the 
 form known to be the best for strength, if executed 
 in masonry, was abandoned ; that, instead oi flaring 
 the faces of the masonry outwards from the throat, 
 the flaring parts were removed, and surfaces parallel 
 
 9 
 
82 
 
 CASEMATE EMBEASXTBES. 
 
 and perpendicular to the surface of tlie scarp-wall 
 substituted. • 
 
 Kg. B. 
 
 By this arrangement the opening available to 
 the enemy's small missiles was reduced to that of 
 the ih/roat, e h, Kg. 5. The same effect might have 
 been accomplished by putting the throat in the face 
 
 Pig. «. 
 
 of the scarp, as in Fig. 6 (which, according to Sir 
 Howard, would have reduced to nothing, the " width 
 " of the parapet ") ; but, for various reasons, it was 
 found more convenient to place it 2 feet within the 
 face. 
 
CASEMATE EMBEASTIRES. 83 
 
 This arrangement leaves an acute angle, a h c, 
 instead of tlie obtuse angle of the old model, ABO 
 (vide Fig. 4) ; and here — ^proceeding from this 
 chmige of form — arose the necessity of strengthen- 
 ing the throat by wrought iron plates. Oxir experi- 
 ments have proved that a solid 8-inch wrought iron 
 throat-plate, solidly hacked against mason/ry^ is 
 capable of stopping a 68-pound shot, fired at 200 
 yards, with no material damage to the embrasure. 
 That, by repeated battering on the same place, the 
 throat may not be broken through, is not pretended. 
 The chances of such repeated hits are exceedingly 
 small, as every sailor knows ; and the structure, 
 military or naval, perfectly invulnerable and per- 
 fectly free from danger, has not been, and never 
 will be, invented. If that happy day arrives, men 
 will probably give up their artificial appliances for 
 fighting and betake themselves again to nature's 
 weapons. 
 
 So much for the form of the American embra- 
 sure, and the objects which have controlled that 
 form and manner of construction. Notwithstanding 
 " the dangers of the throat being broken through," 
 which he so earnestly deprecates. Sir Howard Dou- 
 glas very inconsistently makes the half-way admis- 
 sion, " Perhaps the American embrasure may be 
 " better adapted to the case for which it is designed 
 
84 
 
 CASEMATE EMBEASTXBES. 
 
 " than the ftmnel-sliaped embrasure ;" but imme- 
 diately adds — " However tMs may be, it is not 
 " adapted to, nor even practicable in, the formation 
 " of embrasures in eartben parapets 18 feet thick." 
 The title, " Casemate Embrasures," on the back of 
 the book which describes them, might have ren- 
 dered such a remark imnecessary. 
 
 Kg. T. 
 
 Wj. 8. 
 
CASEMATE EMBRASUBES. 
 
 85 
 
 Fig. 9. 
 
 Pig. 10. 
 
 The preceding sketclies are horizontal sections 
 (drawn to the same scale) of embrasures actually- 
 constructed in recent sea-coast fortifications. Figs. 
 7, 8, and 9 are in European works (the prototype 
 of No. 9 need not be sought far from London), 
 and Fig. 10 is the new " American embrasure." The 
 external openings of the first two are about 54 
 square feet ; that of the third somewhat less (prob- 
 ably 40 or more square feet) ; that of the fourth, 
 measured by the throat (for its peculiar form arrests 
 nearly all nussiles not entering the throat itself), is 
 
86 CASEMATE EMBEASUEES. 
 
 3_9_ square feet. In tte , three former, the sharp, 
 solid angles of masonry at the throat are liable to 
 be broken off (even by shells, or shot of small cali- 
 bres) and forced inwards npon the gunners, en- 
 larging very much the throat (the precise danger 
 Sir Howard compliments the American engineers 
 with dreading). The throat of the latter cannot be 
 broken in, unless by the long-continued hammering 
 of an 8 or 10 inch solid shot upon the same very 
 limited area. This embrasure is practically secure 
 from this danger; it is practically secure against 
 masonry fragments of any kind being carried in 
 from the wall around ; and practically secure against 
 the fragments of projectiles which batter themselves 
 to pieces against the cheeks of flaring embrasures. 
 
 Now, with regard to the grape and canister: 
 but first let me quote two items of evidence taken 
 by the " Commissioners appointed to consider the 
 " defences of the United Kingdom." The witness 
 is Captain B. J. Sullivan, K. K, C. B. 
 
 " Which guns do you consider most efficient — 
 " guns in a work on the hill, which you have 
 "just spoken of, or guns in a casemated battery 
 " at the Warden Ledge ? With raking shot, com- 
 " ing up the Channel, both tiers, but particularly 
 " the lower tier, of a casemated battery would be 
 " as effective as any guns could be ; but, if a ship 
 
CASEMATE EMBKASTJEES. 87 
 
 " attempted to engage it, tlieii I tlimk a casemated 
 " battery tlie most defective. If a ship can "bring 
 " up against ' it, there is no question that a case. 
 " mated battery should only be put where it is not 
 " pos'sible to put an earthen battery." 
 
 " (^CTiai/rmcm.) What are your reasons for that 
 " conclusion ? Because the casemates carry in the 
 " shot in such a large proportion ; and I believe 
 " that if a ship brings up within 200, or 300, or 
 " 400, or 500 yards of a casemated battery, such as 
 " we have seen in the Baltic, the battery must be 
 " silenced. I should have no hesitation in saying 
 " that ships must succeed against a casemated bat- 
 " tery, if they can get close ; and it is the only 
 " class of battery which they could succeed against 
 " If the embrasure were reversed, it would increase 
 " the power of the battery over the ship tenfold ; 
 " and then I should think that a casemated battery 
 " would beat any ship which could be brought 
 " against it." (Italics my own.) 
 
 " If the embrasure were reversed'''' — Captain 
 Sullivan hit the mark exactly that time. He had 
 seen these immense embrasures — almost large enough 
 to drive a cart through, "in the Baltic"* (per 
 haps, too, m tlie Channel) — staring him in the face. 
 
 * They were equally to be seen in the Black Sea. 
 
88 CASEMATE EMBEASTJEES. 
 
 If a little light was sldning in from tlie rear of 
 the casemate, he may have seen the men moving 
 about inside. Well might he respond, when asked 
 why " a casemated battery should only be put 
 " where it is not possible to put an earthen bat- 
 " tery," 't Because the casemates carry in shot in 
 " such a large proportion." Indeed those he had 
 seen looked as if they were made on purpose to 
 do so. Captain Sullivan will perceive that we — 
 Americans — ^have been acting on his idea to the 
 utmost extent our materials would admit ever 
 since we commenced making " casemated batteries," 
 and that now — ^by the introduction of iron we 
 have practically fulfilled it — ^we have " reversed the 
 " embrasv/rer 
 
 Let us now see the effects of this arrangement, 
 as regards grape and canister. (I extract a few 
 paragraphs from General Totten's report, in which 
 the matter is treated ftdly.) 
 
 Suppose a hundred-gun ship to be placed within 
 good canister range of a casemated battery of about 
 the ship's length and height; to the 50 guns of 
 the ship's broadside there would be opposed about 
 24 guns, in two tiers, in the battery. The ship 
 would fire each gun in three minutes, or ten times 
 in half an hour ; the 50 guns would therefore make 
 500 discharges within that time. 
 
CASEMATE EMBEASUEES. 89 
 
 With 156 balls in eacli 32-pdr. canister (weigli- 
 ing in all 31^ lbs.), there would be thrown 78,000 
 balls in 30 minutes. Supposing one half to miss 
 the fort — which, considering the size of the object 
 and the short distance, is a very large allowance — 
 there would still remaiu the number of 39,000 balls 
 to strike a surface of (say) 6,000 square feet ; that 
 is, on each square foot, 6J balls. 
 
 Should this idea be carried still farther, as it 
 ought, and the ship's canisters be filled with musket 
 balls — each 32-pdr. canister holding 639 balls — ^the 
 number of balls to the square foot of surface of 
 the battery would be 26. And the comparative 
 nmnbers of missiles "carried in" to the casemates 
 by embrasures of the external area of figs. 1 and 2, 
 and the new American embrasure, would be — 
 
 Gun 32-pdr., firing iron balls of 1.05 inch in diameter — 
 
 Through the throat of American embrasure, 25 balls. 
 
 Within exterior opening of European embrasure,. . . . 351 " 
 
 8-inch gun, firing iron balls of 1.05 inch in diameter — 
 
 Through the throat of American embrasure, 46 " 
 
 Within exterior opening of European embrasure 648 " 
 
 Gun 32-pdr., firing canisters filled with musket balls — 
 
 Through the throat of American embrasure, 101 " 
 
 Within exterior opening of European embrasure, .... 1,404 " 
 
 8-inch gun, firing canisters filled with musket balls — 
 
 Through the throat of American embrasure, 198 " 
 
 Within exterior opening of European embrasure, .... 2,754 " 
 
90 CASEMATE EMBEAStTBES. 
 
 By means of wrouglit iron shutters, proof against 
 tlie largest grapeshot, by far tte greater proportion 
 (probably nine tentbs) of tlie small missiles mentioned 
 above as coming tbrough tbe tliroat of tbe Ameri- 
 can embrasure will he excluded. Comment is un- 
 necessary ; probably no safer arrangement, by wMch 
 to put a gun in battery against sMpping, can be 
 contrived tban tie " casemated battery" witb (to 
 borrow Captain Sullivan's bappy expression) " em, 
 " hrasures reversed" and provided witb grape-proof 
 stutters. 
 
 The work of Sir Howard Douglas on " Naval 
 " Gunnery" bas been usually recognized as of Mgb 
 autbority. It is in tbe hands of almost every 
 naval officer, of almost every military engineer, and 
 of almost every artillerist in the United States. 
 It becomes, therefore, the more important to scruti- 
 nize statements which he puts forth with a con- 
 fidence which seems to imply that there is no room 
 for denial, or, at least, that irrefragable evidence 
 for them is furnished in his work, — ^like the fol- 
 lowing : — 
 
 " The very worst combination of materials that 
 " can be made ia the formation and strengthening 
 " of defensive works is that which consists of two 
 " hard, rigid, brittle, and splintering materials — 
 " stone and iron — acting and re-acting vehemently 
 
CASEMATE EMBKASTXEES. 91 
 
 " upon eacli otter on the impact of every shot ; 
 " and wMcli fully explains the causes of the ener- 
 " getic vibrations, concussions, and displacements re- 
 " ported on page 138 of General Totten's work, 
 " inserted in Art. 434* The combination of tim- 
 " ber and iron is not so bad, on account of the 
 " elasticity of the timber, by vrhich the blow is 
 " somewhat cushioned. A facing of earth to a 
 " stone wall, as practiced at Sevastopol, is a far 
 " better cover ; but best of all is a parapet of 
 " earth — good, well-rammed earth — ^with an escarp 
 " wall to the rampart below." 
 
 Now, if we turn to his chapter headed " Metallic 
 " defences to batteries" (16 pages), we do not find 
 a solitary example of an experiment upon a " com- 
 " bination of masonry and iron," nor a case in 
 which masonry enters at all. If we turn to that 
 headed " Masonry defences strengthened by a com- 
 " bination of iron slabs" (26 pages), we find no 
 experimental facts whatever relating to this head- 
 ing other than three instances (paragraphs 424, 
 
 * It is worth while here to mention that the " energetic vihrations, con- 
 " cuasions, and displacements" took place in the extreme end of a bit of a 
 wall 10 feet high, 5 feet thick, unsupported by counter-forts or other masses, 
 and " very much shattered (as General Totten states in another place) by 
 previous firings, and that they were described rather for their scientific 
 interest than as any example of the effect of a 128-lb. shot upon the wall of 
 a casemated battery. 
 
92 CASEMATE EMBEASITEES. 
 
 426, 427) taken from General Totten's experiments, 
 of trifling importance in themselves (from the 
 nature of the materials and combinations in the 
 embrasure fired at), and totally unmeaning and mis- 
 leading, detached, as they are, from the rest. 
 
 The sonorous phraseology just quoted must, 
 therefore (like coins), be taken by its ring, unless, 
 indeed, our irreverence permits us to search out 
 evidence and form opinions for ourselves. Let us 
 hear it again, however : " The combination of tim- 
 " ber and iron is not so bad, on account of the 
 " elasticity of the timber," <fec., &c. Dogmatic 
 assertion, so vague as to take no account of the 
 meaning of the words used (e. g., which includes 
 wrought iron in the category of " brittle and splinter- 
 " ing materials"), will carry no conviction without 
 evidence, and against evidence. Our opinions are 
 different. 
 
 That the 8-inch wrought iron throat-plate of our 
 embrasure should offer an effectual resistance to 
 heavy shot, we believe that it must be solidly 
 hacked by masonry. We believe that to put an 
 " elastic material" behind the iron is to ensure its 
 destruction (unless the thickness of iron is enor- 
 mous). 
 
 Our own experiments justify this belief; so 
 also the experiments we see recorded on detached 
 
CASEMATE EMBEASUEES. 93 
 
 iron plates, and on plates attached to the sides of 
 floating-batteries. The more unyielding and in- 
 elastic the backing, the more invulnerable is the 
 plate. And this opinion is confirmed by more 
 recent evidence. "We are told," says the writer 
 on " Iron-clad ships of "war," in Blackwood, " that 
 " Armstrong's 100-ponnders and the solid 68-pound- 
 " ers lately tried on a 6-inch plated embrasure, at 
 " Shoebujyness, Tnade no impression^ although the 
 " sProke was so violent that one projectile actually 
 " recoiled bach into the traverse where the committee 
 " were watching for the effect ;" and the author of 
 " Iron sides and wooden walls," in the London 
 Quarterly, says : — " It is by no means clear that 
 " this lining of wood in the ' Warrior,' and especially 
 " in the French vessels, is not entirely a mistake. 
 " It is almost certain tha,t the buckling of the plates 
 " and starting of the bolts, in the ' Trusty,' were 
 " due to the elasticity of the cushion to which they 
 " were attached. Still more clear that the success — 
 " in the Admiralty sense of the term — of the ex- 
 " periments at Portsmouth was owing to the 
 " yielding of the target. A very thin plate attached 
 " to a gra/nite hlock, or any v/nyielding substance, 
 " will resist almost any blow ; and if two more 
 " inches of iron were added to the thickness of the 
 " 'Warrior's' sides instead of the teak, it is more 
 
94 CASEMATE EMBEASUBES. 
 
 " than probaUe that, with the same weight, she 
 " would resist the impact of shot to a much greater 
 " extent." Yet, if we are to believe the " London 
 " Times," Mr. Whitworth acknowledges that the 
 " "Warrior," with her 20 inches of solid teak, is 
 practically invulnerable, even to his famous " bolts." 
 
 Were there a perfectly inelastic mass of masonry 
 behind a 5-inch plate, it would probably defy the 
 repeated efforts of this most penetrating of project- 
 iles, even at tm, yards. 
 
 But we have yet missed the main point to 
 which, after all. Sir Howard's disapproval of the 
 American embrasure, and his unbelief in iron — 
 particularly in that "very worst combination of 
 " materials," masonry and iron — ^leads him : or more 
 probably the point from which he started. He not 
 only passes judgment upon the American embrasure, 
 but upon the works which contain them. " It ap- 
 " pears," he says, " to the author that the remedies 
 " proposed to strengthen the casemate embrasures 
 " is the strongest proof of the original error of hav- 
 " ing constructed works of this description, so as to 
 " render it absolutely imperative upon the engi- 
 " neers of the United States to endeavor to remedy 
 " defects inherent in masonry defences, or to replace 
 " them by earthen works. This observation, if 
 " followed up, would lead to a very large question, 
 
CASEMATE EMBBASTJEIS. 95 
 
 " on wMcli it would be out of place to enter ; but 
 " the author may refer to Ms work lately published 
 " on ' Fortification,' in whicli that question is fully 
 " discussed, in examining the controversy which 
 " has long been carried on between the French and 
 " German engineers on earthen works against ma- 
 " sonry works, — the French engineers adhering to 
 " the bastioned system, Avith parapets of earth, <fec." 
 
 This indeed " would lead to a very large ques- 
 "tion" — a question which has been thoroughly 
 discussed (in this country, at least) in its proper 
 bearings, vi^. : " Whether masonry casemated bat- 
 " teries are proper and eligible for sea-coast defence^ 
 
 Our own engineer reports treat the subject in 
 full, and I have taken my part in the discussion, 
 so far as the affairs of the Allied fleets against the 
 Russian casemated works throw any new light upon 
 the subject* It would be sufficient here to say that 
 in no svngle case in which fleets have contended with 
 masonry works have the results of their cannonade 
 upon masonry walls been such as to indicate that 
 the latter were not capable of sufficient endurance — 
 that they were not, after the action, so little dam- 
 aged as to be, to all intents and purposes, intact. 
 Some injury was perhaps done to the masonry walls 
 of Kinburn, but the work was " dilapidated " and 
 
 * " Dangers and Defences of New York." 
 
96 CASEMATE EMBKASUEBS. 
 
 almost insusceptible of defence, the guns of low 
 calibres and in " barbette," and the attacking force 
 overwhelming in numbers and weight of metal. 
 
 The useless cannonade of Sevastopol, October 
 17, 1854, produced so little effect on the most 
 exposed work (Fort Constantine) that the Russian 
 official accounts do not acknowledge that any dam- 
 age was inflicted "other than injury to the guns 
 " and parapet of the crown " of that fortress where 
 the cannon and men were exposed* (i. e., the bar- 
 bette, not the casemate battery). 
 
 Bomarsund — a single "masonry casemated castle" 
 — after it had defied a large fleet, " went down like 
 " a pack of cards " before a small Icmd batteryf of 
 32-pounders. Yet these works, with their embra- 
 sures turned wrong end foremost — with external 
 openings arranged to "carry in" the largest pos- 
 sible quantity of shot — ^with throats exhibiting 
 acute solid angles of a brittle material — presented 
 casemate guns under the most imfavorable circum- 
 stances in which they could be arranged in a case- 
 mated battery. Yet it was the barbette guns of 
 Fort Constantine that appear to have suffered most, 
 and the walls were practically uninjured. 
 
 * See 2d note to page 49, and also my aeeount of these affairs in "Dangers 
 and Defences," Ac. ; also " Naval Gunnery," par. 361. 
 \ See note to page 49. 
 
CASEMATE EMBEASUEES. 9*7 
 
 Open earthen batteries are excellent emplace- 
 ments for sea-coast guns in certain cases, but it is 
 rare that sncli favorable sites offer themselves (for 
 example, at Sevastopol there was not a site of the 
 kind suitable for defending the ent/rance of the 
 harbor), and also rare that a sufficient number of 
 guns can be accommodated on earthen batteries 
 when they do offer themselves. 
 
 For low sites, which can be approached within 
 grapeshot range, such batteries are inadmissihle. 
 Earthen embrasures in such locations furnish poor 
 protection to the gunners against the showers of 
 grape which may be poured upon them from ships' 
 guns, — still less against sharp-shooting from the top- 
 masts.* To build an artificial site in a channel- 
 way (like that of Fort Calhoun, in Hampton Roads, 
 or like those sites the British Commissioners pro- 
 
 * American engineers discard " earthen embrasures" for sea-coast guns (in 
 barbette batteries) almost entirely, on account of their limiting the traverse 
 of the gun to so small an angle as 30°. Captain SuUivan gives us some 
 interesting testimony on this point, also. 
 
 " {Sir Frederick Abbott.) Am I to understand you that a barbette bat- 
 " tery would make a good fight against a ship ? — Nothing, I believe, will 
 " contend with a ship equal to a barbette gun with raised traversing plat- 
 " forms. However large an embrasure may be, it can never give the sweep 
 " which a barbette gun can give. Wherever guns are confined in embra- 
 " snres, it is certain that ships can take up a position just shutting in the 
 " embrasures, where not a gun can fire on them, when barbette guns in the 
 " same position would fire on them ; and it is for that reason alone that I 
 " think a barbette battery has an advantage over any embrasures." 
 10 
 
98 CASEMATE EMBEASTTEES. 
 
 pose to build for the defence of Spittead), and to 
 put an "earthen battery" on it, would be the 
 height of absurdity; and yet otherwise than on 
 such artificial sites there can be no permanent 
 defences to those waters. 
 
 This discussion — exhausted long before — need 
 not be carried further here. When, however, an 
 authority so high as Sir Howard Douglas alludes 
 to this "very large question," and refers the 
 reader to " his work, lately published, on Fortiflca- 
 " tion, in which that question is fully discussed," 
 the latter turns to that work with no little curiosity. 
 With a miad preoccupied with the subject of " sea- 
 " coast defence," and the relative expediency of 
 putting guns in " masonry casemates," or earthen 
 batteries, he will probably be somewhat "taken 
 " ab^ck " to find in it nothing but a reprint of the 
 authcff's views (published 40 years ago) on the 
 Carnot system of fortification and defence by curved 
 fires of small projectiles (comprising a repetition of 
 that " mxyrceau choisi " of all the opposers of the 
 German system of fortification, the Woolwich ex- 
 periments on the " Carnot wall "), and accounts and 
 criticisms of the German system, taken mainly from 
 the well-known French works of Mangin, Maurice 
 de Sellon, &c. The reader — ^his mind occupied with 
 the subjects I hav« mentioned, and referred to this 
 
CASEMATE EMBEASUEES. 99 
 
 work for a " Ml discussion " — ^will be no less taken 
 aback to find himself tlius confronted witli old 
 acquaintances, tlian puzzled to imagine what 
 (hitherto unsuspected) business they have with the 
 matter in hand ; until perchance the thought strikes 
 him that Sir Howard, mystified, perhaps, by his 
 Germail studies, has confounded the principle — older 
 than Vauban, and certainly not disowned by the 
 Germans (however much their works may be open 
 to stricture for its practical violation) — that the 
 masonry of a front of fortification should not be 
 exposed to the besieger's Icmd batteries, with the 
 question as to the capability of masonry sea-coast 
 J>atterie8 to contend with ships.* A reference to his 
 " Naval Gunnery " might, I should think, have con- 
 vinced him that there was — when a masonry work 
 went down " like a pack of cards " before the con- 
 centrated fire of a small land battery, at 900 yards, 
 yet resisted the " most powerful ordnance in the 
 
 * No nation in the world has used masonry sea-coast batteries more 
 extensively than France — witness Cherbourg, Brest, Cette, Marseilles, 
 Toulon (and, I presume, every other French sea-port, — not only masonry 
 works, with walls exposed from top to bottom to naval cannonade, but case- 
 mated works, with their guns firing through masonry embrasures. The 
 "French engineers," who, according to Sir Howard, "adhere to the bastion 
 "system, with parapets of earth," will probably be enlightened by the 
 discovery that the controversies as to the relative merits of the French and 
 German systems have anything to do with this subject. 
 
100 CASEMATE EMBEASITEES. 
 
 Britisli navy," directed first from 900, then from 
 400 yards, wittont a real breacli "being made (al- 
 tliougli the deserted walls made tw response to the 
 floating structure wHcli assailed it) — some slight 
 differences of fact and argument to be used in the 
 treatment of these two subjects. However that 
 may be, it is the first time that we, on this* side of 
 the water — ^though tolerably well acquainted with 
 the " German system" — ^have ever suspected that the 
 works that Sir Howard has anglicized contained a 
 " full discussion," or any discussion at all, of the 
 proper kind of constructions for sea-coast defence, 
 or, indeed, had the slightest connection with the 
 subject. 
 
CASEMATE EMBEASUEES. 101 
 
 [POSTSCEIPTUM.] 
 
 Since the al>ove pages were placed in tlie 
 printer's hands, I have seen Sir Howard Douglas's 
 " Postscript to the section on Iron Defences, con- 
 " tained in the 5th edition of the Naval Gunnery, 
 " in answer to the erroneous principles set forth by 
 " the Reviewer in the Quarterly Eeview, for Octo- 
 " ber, 1860." 
 
 The question of " Iron sides versus wooden 
 " walls " is not one which I am competent, profes- 
 sionally, to discuss. In the preceding pages I have 
 indicated perhaps sufficiently my concurrence with 
 those naval authorities who believe that to some 
 more perfect protection against modern projectiles 
 the course of things must inevitably tend, and that 
 iron will probably be the material through which 
 this protection will be gained. But it is quite suffi- 
 cient for me, as an engineer, to take the facts as I 
 find them : that iron floating-batteries have actually 
 been constructed expressly for the attack of fortifi- 
 cations, and that they are regarded by high naval 
 authorities as among the established means of such 
 attack ; that both France and England are actually 
 
102 CASEMATE EMBKASTJEES. 
 
 constructing iron sMps of war ; and that there are 
 those who vaunt the ability of such ships to " en- 
 " gage, at breaching distance, any land battery." 
 Expressing my entire disbelief in this opinion, it is 
 none the less proper that those who have to design 
 or construct land batteries should have a full antici- 
 pation of what their works will or mwy prohably 
 have to contend with ; and to show that they wiU 
 not be found wanting against such probable tests.* 
 In this " Postscript," however. Sir Howard has, 
 in two places, reiterated his erroneous assertions as 
 to the embrasure experiments in the United States, 
 in reference to which I have attempted to prove 
 that he does not only not at all understand the 
 system which he condemns, but that he has not even 
 " attentively read " the report of General Totten, on 
 which he bases his opinions. As previously stated 
 (in the text), more than five hundred Tiew embra- 
 sures on General Totten's system have been built, 
 within the last four or five years, in fortifications in 
 course of construction. On what real basis, then, 
 rests the claim to " authority " (which Sir Howard 
 tells us is conceded to " Naval Gunnery " all the 
 
 * It is proper here to remark that guns of " extraordinary " calibre were 
 urged by the Engineer Department of the United States, for the purposes of 
 sea-coast defence, long before iron-clad floating-batteries or ships were 
 thought of. 
 
CASEMATE EMBRASURES. 103 
 
 world over) of the work wliicli uses language like 
 the following, — and that, too, with General Totten's 
 Eeport before him, and without a word of conflict- 
 ing evidence from any other quarter ; — * * " The 
 ' prophecy of General Totten is not on the eve of 
 fulfillment ; for his proposition to combine iron 
 with masonry, to defend the throats of casemate 
 embrasures in masonry defences, had been tried, 
 was not successful, and never will be fulfilled ; for 
 the very worst combination that can be made of 
 materials for defensive purposes is that of stone 
 ' and iron, which, from their rigid, brittle qualities, 
 ' act vehemently on each other, and shake the whole 
 ' fabric so formed." What claim to be considered 
 a careful, accurate, and candid sifter of facts, can 
 the writer have who, with General Totten's report 
 before him, announcing, in its concluding paragraph, 
 the approval, by the American War Department, 
 of his system, has asserted, in this authoritative 
 manner, the disapproval of that Department — (the 
 very curious manner in which Sir Howard discovers 
 the decision of the Department in two paragraphs 
 of my letter to the Secretary of War is alluded to 
 in the text) — and who, while continually reiterating 
 his favorite phrase, " the very worst combination that 
 " can be made of materials," &c., &c., fails to support 
 this opinion by one single experimental fact as to 
 
104 CASEMATE EMBEAStJEES. 
 
 the combination of stone and iron (for those two or 
 three cases of " firings," taken from General Totten's 
 report, detached from the rest, have not the slight- 
 est significance), and who calls wrought ojcon a 
 " brittle and splintering material ? " 
 
 There is one other matter in the Postscript on 
 which I would say a few words, as it has some 
 relation to the value of guns in casemates, viz., the 
 greater damage done to the vessels of the detached 
 squadron at Sevastopol by the guns of the " Wasp " 
 battery (1,200 yards distant) over that inflicted 
 by those of Fort Constantine (700 or 800 yards 
 distant), with which the squadron was immediately 
 engaged. Sir Howard makes allusion to it as 
 follows : — ■ 
 
 " In the letter signed ' A Captain, K. N.,' which 
 " recently appeared in the ' Times,' the writer 
 " appears to think that he has decisively settled the 
 " question in favor of iron-sided ships by stating 
 " that the severe damage sustained by the British 
 " fleet in the bombardment of Sevastopol, on the 
 " 17th of October, 1854, would have been prevented 
 " had the sides of our line-of-battle ships been pro- 
 " tected by iron plates. But the ' Captain, B. N.,' 
 " who says he served there, seems not rightly to 
 " understand the case. The fire which did such 
 " damage to the British ships, and from which they 
 
CASEMATE EMBRASURES. 105 
 
 " were forced to witlidraw, was not horizontal fire, 
 " but plunging, direct fire, from tlie Wasp and 
 " Telegraph batteries, placed on the summit of the 
 " cliif, and against which those ships could not have 
 " been protected unless their decks had been covered 
 " with shot-proof iron plates. According to this 
 " very erroneous conclusion, published on the 
 " authority of an officer — ^present, as he states, at 
 " that affair — we see how it has been run away 
 " with, and carried to the credit of iron-sided 
 " ships." 
 
 "Whether "A Captain, K. K," who "served 
 " there," was able to " understand the case," or not, 
 I cannot say ; but " A Captain, E, N.," who served 
 there on the Aga/memnon, ought to understand it. 
 Hear Captain Cowper P. Coles' evidence (" Evidence 
 " taken before the Commissioners, &c.") : — 
 
 " 397. {Chairman?) Have you any idea what 
 " was the nature of the guns which they fired at 
 " you ? — The Eussian 32-pounders, which, I think, 
 " are a trifle larger than ours." 
 
 " 398. {Sir Frederick Abbott.) Were those the 
 
 " largest ? — ^Those at the Wasp Fort, I imagine, were 
 
 " 68-pounders." 
 
 * * -X- * * * 
 
 " 439. {Sir Fredericlc Abbott.) You have stated 
 " that the fire from the Wasp Fort was more 
 
106 CASEMATE EMBEASTJEES. 
 
 " destructive, or annoying, tlian tliat from any other 
 
 " fort ; will you explain why ? — I fancy that they 
 
 " «ould see better through the smoke, from having 
 
 " no embrasures (I would here wish to remark that 
 
 " embrasures in casemated forts, when once filled up 
 
 " with smoke, obscure the sight), and, being high 
 
 " up, they were less molested by the fire of the 
 
 " ships, to a certain extent ; but I also imagine that 
 
 " they had superior gunners in Wasp Fort, for it 
 
 " was hardly ever known to make a bad shot. 
 
 "441. (jSir Frederick Alhott.) Then the advant- 
 
 " age was not at all connected with the direction 
 
 " of the shot, — ^that is to say, its coming down from 
 
 " a greater height upon your decks ? — No ; the angle 
 
 " would be so little that I do not think that it 
 
 " made any great difference ; but it was also in a 
 
 " raking position, as Wasp Fort was on our 
 
 " quarter." 
 
 ****** 
 
 " 450. (^Chairmcm.) Do you think that if the 
 " Wasp Battery had been higher or lower its fire 
 " would have been more effective ?— If lower, they 
 " could have laid their guns with more precision ; 
 " they could have taken better shots ; but being 
 " high enabled them to have a better view of the 
 " ships over the smoke." 
 
CASEMATE EMBEASTJEES. 107 
 
 And Commander DaUgren, U. S. N., speaks as 
 follows : — 
 
 " The value of tlie small works on the cape and 
 " bluffs was clearly defined in these results ; being 
 " above the dense cloud of smoke that enveloped 
 " the ships and the lower forts, their aim was not 
 " embarrassed ; while the seamen labored under the 
 " difficulty of firing, with an inconvenient elevation, 
 " at objects that they saw but seldom, and then but 
 " dimly and briefly." • 
 
 Command, in a shore battery, has, doubtless, its 
 advantages, where it can be attained (which is far 
 from being usually the case). But batteries "d fleur 
 d'eau " have also their advantages ; and, for the 
 great majority of cases, no command can be attained 
 except by piling guns in triple and quadruple tiers 
 in casemates. The actual plunging effect, so strongly 
 insisted upon by Sir Howard, is very trifling from 
 batteries even as high as 120 or 150 feet, beyond 
 600 or 800 yards ; and the ricochet of such batteries 
 is lost. Captain Coles points out very clearly the 
 advantages of the Wasp battery, — viz., larger- 
 calibred guns, better gunners, a clearer view over 
 the smoke, greater difficulty in hitting the battery 
 from the ships, <fec., &c. The plunging effect (as 
 due to command^ of a battery 130 feet high, upon 
 ships 1,200 yards distant, amounts to nothing. The 
 
108 CASEMATE EMBEASUEES. 
 
 angle wMcli a line, drawn from the deck of tlie sMp 
 to the battery, would make witk the horizontal, 
 would be about 2°. The angle of descent of ^ the 
 shot would be somewhat greater. If the battery 
 were " d fev/r d^eau" the elevation of the gun 
 necessary for the range would be about 2° ; and the 
 descending shot would make an angle, probably, 
 fully equal to what it would make in the other case. 
 I have stated already that casemate guns could 
 not be exhibited under more disadvantageous cir- 
 cumstances than they were in. those Russian works. 
 Embrasures of enormous dimensions, with sharp 
 angles of masonry at their throats, are not combina- 
 tions under which American engineers advocate the 
 advantages of casemated batteries. Add to these 
 disadvantages the low calibre of the guns, and the 
 fact that a wooden fleet was not destroyed (three of 
 the five vessels originally engaged were driven off 
 crippled, so also the " Queen," which came to their 
 aid, soon after she got into her position), is intel- 
 ligible. The " Agamemnon " received 240 shots or 
 shells (Captain Coles mentions but three shells, " one 
 " which burst on the main deck, and two in the 
 " bunt of the main-yard ") ; had she received but 
 half a dozen shells and solid shot of sufficient cali- 
 bres, she would probably have been disabled. In 
 writing on this subject once before, I stated (and I 
 
CASEMATE EMBEASTJEES. 109 
 
 believe the facts justify tlie statement) " tliat it is 
 " only due to tlie inefficiency " (in respect to calibre) 
 " of tlie projectiles by whicli she was struck that 
 " she was not destroyed." 
 
 In conclusion, I would state that the defence of 
 the American system of sea-coast fortifications 
 against the strictures of Sir Howard Douglas has 
 been with me no labor of love. Much more grate- 
 ful would it have been to have had only to recipro- 
 cate the expressions of regard and professional 
 respect which he uses in speaking not only of 
 American naval officers, but of American engineers. 
 I hesitated long, after the appearance of the 5th 
 edition of his " Naval Gunnery," to undertake this 
 work. My first impulse was to address Sir Howard 
 a private letter, asking a correction of errors of 
 statement, and the giving of a just view of what the 
 American embrasure and the American system of 
 casemated works actually were. Those who have 
 read these pages will, I think, concur vsdth me in 
 the opinion that that course would have been quite 
 insufficient. The " Naval Gunnery " is widely re- 
 ceived as of the highest authority, being (according 
 to his own statements) translated into several Euro- 
 pean languages. 
 
 American engineers have a right to claim that 
 their Avorks shall not be condemned in it -sA-ithout 
 
110 CASEMATE EMBBASURES. 
 
 proper information or imderstandirig of tliein ; and, 
 if noticed at all, that it shall be in a manner wMch 
 does not betray such complete want of accurate 
 information and such a readiness to overlook the 
 actual facts, or to find in them only what will sanc- 
 tion what appear to be the prejudgments of the 
 author on matters which have now assumed a high 
 importance and which have been dragged into the 
 arena of controversy. 
 
ERRATA. 
 
 Page 28, note^ 5th line, for " she," read " they." 
 
 Page 55, 2d line, for " rotary," read " rotation." 
 
 Page 89, line 15, instead of " figs. 1 and 2," read " figs. 7 and 8." 
 
 Page 94, 17th line, for " embrasure," read " embrasures." 
 
 Note to page 99. — The author's language may be excepted to as doing injustice to 
 Sir Howard's meaning. It may be alleged that his argument from the German system 
 rests simply upon his assumed proof of the impropriety of placing guns in casemates, be- 
 hind masonry walls, as practiced iov Jtanking purposes in that system. It matters little, 
 however, as to my argument. 
 
 The reliance upon " caseraated caponni^re defences," for purposes vital to the security 
 of a place (*. c, for the flanking defence), upon which may be concentrated the curved 
 fire of the besieger's batteries, from the second parallel, or the direct fire of his counter- 
 batteries, from the crest of the covert-way, is so entirely different a matter from the use of 
 guns in casemates for sea-coast defence, that the reader of his work may well be excused 
 for mistaking what the pith of his " full discussion " consists in. 
 
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