Santa Rosa bay. On the west the lagoons of Pensacola, Perdido, and Mobile bays, respectively, interlock in such a manner as to require but a few miles of cutting to complete a navigable channel from the first to the last named bay, and thence through an existing interior water communication to the city of New Orleans. Pensacola bay has rare properties as a harbor. It is now accessible to frigates, and there is reason to hope that the bar may be permanently deepened. The bar is near the coast and the channel across it straight and easily hit. The harbor is perfectly landlocked and the roadstead very capacious. There are excellent positions within for repairing, building, and launching vessels, and for docks and dock yards, in healthy situations. The supply of good water is abundant. The harbor is perfectly defensible. These properties, in connexion with the position of the harbor, as regards the coast, have induced the government to select it as a naval station and place of rendezvous and repair. An excellent survey has been made of the bay of Pensacola, sufficing to form the scheme of defence for the town and harbor. Regarded, however, as an important naval station and place of rendezvous and repair, which it now is, further surveys, extending a greater distance back from the shores, delineating accurately the face of the country, and showing the several avenues by land and water, are found to be necessary. The defences of the water passage as projected are nearly completed. Fort McRae, on Foster's island, is also finished; as is Fort Barrancas, on the site of an old Spanish fort. An old Spanish water battery has been thoroughly repaired, and placed in connexion with the last-named fort, and considerable progress has been made on a redoubt, in advance of the same fort. Permanent barracks in the same vicinity are about half finished. The site of Fort McRae was, a few years since, seriously threatened by the abrasion of a new outlet from the lagoon that lies just behind it; but this danger has been averted, and by the erection of a low rampart exterior to the fort a permanent security against any recurrence of the danger will be provided, and place for a heavy additional battery acting on the channel will be prepared. At a future day it will be proper to extend this exterior protection. At present it is designed to execute only that part lying over or nearly over the outlet that was lately so threatening and so difficult to close. Estimated at $204,000.— (Classes A, B, C.) Perdido bay. This bay is intimately related to Pensacola and Mobile bays, both as regards security and intercommunication, and should be carefully surveyed with a view to those objects. It must be fortified, and the cost may be $200,000.-(Class F.) Mobile bay. The plan of defence for this bay requires a fort on Mobile. Point, and another on Dauphin island. Fort Morgan, at the first-mentioned position, is a finished work, in an efficient condition, but requiring, in the way of barracks and quarters, storehouses, &c., for the accommodation of its garrison, some further expenditures. These improvements are in progress-estimated at $30,000.-(Class B.) Fort Gaines, on Dauphin island, has been authorized by Congress, and the expenditure of the appropriation awaits only the settlement of title to the site, as to which there are supposed to be no remaining difficulties. Estimate, $180,000.-(Class C.) New Orleans and the delta of the Mississippi.-The most northern water communication between the Mississippi and the Gulf is by the passage called the Rigolets, connecting Lake Borgne and Lake Pontchartrain. The next is the pass of Chef Menteur, also connecting these lakes. Through these passages an enemy entering Lake Pontchartrain would, at the same time that he intercepted all water communication with Mobile and Pensacola, be able to reach New Orleans from the southern shore of the lake; or he might continue onward through Lake Maurepas, Amité river, and Iberville river, thereby reaching the Mississippi at the very head of the Delta; or, landing within the mouths of the Chef Menteur, he might move against the city, along the edge of the Gentilly road. To the southwest of Chef Menteur, and towards the head of Lake Borgne, is Bayou Bienvenue, a navigable channel, (the one followed by the English army in the last war,) not running quite to the Mississippi, but bounded by shores of such a nature as to enable troops to march from the point of debarkation to the city. These avenues are defended by Fort Pike, at the Rigolets; by Fort Macomb, formerly Fort Wood, at Chef Menteur; by a small fort at Bayou Bienvenue, and by a tower at Bayou Dupré. The defences of the Mississippi are placed at the Plaquemine turn, about seventy miles below New Orleans-the lowest position that can be occupied. Fort Jackson is on the right bank, and Fort St. Philip a little higher up on the left. Forts Pike, Macomb, Battery Bienvenue, and Tower Dupré, have been put in the most efficient state, and will perfectly accomplish the objects for which they were designed. They will still need some small expenditures in reference to security of site, extension of accommodations, &c. Fort Jackson is also in good condition as to its batteries, but will be much improved in that respect on the completion of an outwork now in hand. It needs also more barrack room. Fort St. Philip is a very old fort, and much dilapidated. Its position is so commanding and advantageous as to require the fort to be put in the best state, and much has been done to that end within a few years; still more is necessary for the fort itself and its dependencies; and all the barracks, quarters, and storehouses have yet to be built. Estimated at $111,500.-(Classes A and B.) The most western avenue by which New Orleans is approachable from the sea passes on the west side of the island of Grande Terre into Barrataria bay, which is an excellent harbor for a floating force, guarding the coasting trade on that side of the Mississippi. From this bay there are several passages leading to New Orleans. Fort Livingston has been erected on the west end of Grande Terre island. This fort is kept from entire completion to await the cessation of a slight subsidence which has been going on for some time. It could be finished with the means now applicable at any moment by a few weeks' work.-(Class B.) Proctor's Lake, on Lake Borgne.-This position, which was overlooked in the original project for the defences of the city of New Orleans, has been already adverted to. A small battery, enclosing a tower, standing on the shore, would effectually close this avenue. The tower could not be carried by assault, nor the battery while protected by the tower. No landing could be made under its fire, and there is no other spot for a landing, owing to the swampy nature of the ground, but the site of the battery. Estimated at $100,000.-(Class D.) Several times in this report we have alluded to circumstances which would demand the employment of floating defences in addition to fixed defences upon the shore. We have here an instance in which that kind of defence would be very useful. Fortifications will enable us to protect New Orleans even from the most serious and determined efforts of an enemy; but, owing to the great width of some of the exterior passages, we cannot by fortifications alone deprive an enemy of anchorages, (especially that of Chandeleur island,) nor cover entirely the exterior water communication between the Rigolets and Mobile. We must, therefore, either quietly submit to the annoyance and injury that an enemy in possession of these passages may inflict, or avert them by a timely preparation of a floating force adapted to their peculiar navigation, and capable, under the shelter of forts, of being always on the alert, and of assuming an offensive or defensive attitude, according to the designs, conduct, or situation of the enemy. A floating force of this nature would be very useful in overlooking the coast eastward of New Orleans, especially the portion just mentioned, extending from the Rigolets (Fort Pike) to Mobile bay. And in connexion with the active service of such a force, and as a further defence of the approaches to New Orleans from that quarter, a fort on Ship island would be important. It would cover an excellent anchorage for the defensive flotilla and for other cruisers. With this refuge at one end of the base of operations, and at the other the anchorage between Pelican island and Dauphin island, guarded by works at the eastern end of the latter, a light steam squadron might, without being much exposed, be very effective. Projects have not yet been made for works on Ship island, but it may be estimated that an adequate fort would cost about $200,000.-(Class E.) In this age of great improvements in the means of locomotion, it would be unwise to decide, without pressing need, on the details of the floating force required at certain points on the Atlantic and Gulf of Mexico coasts-perhaps even on the nature of the moving power. Although the probability undoubtedly is that the power will be steam, genius may in the interim devise something still better than steam. And I may here remark, in relation to the preparation of steam vessels for warlike purposes generally, that wisdom would seem to direct a very cautious and deliberate progress. Every new vessel may be expected to surpass in important particulars all that had preceded, and to surpass the more, as each succeeding vessel should be the result of careful study and trial of the preceding. It may be considered unreasonable to expect that steam itself will give way to some agent still more potent, and at the same time not less safe and manageable. But it certainly is no more than probable that steam vessels now under construction may be regarded almost as incumbrances within ten years. A deliberate advance in this branch of naval construction is recommended the more, by our ability to construct these vessels in large numbers, when about to be needed, the timber being collected in the meantime. COAST OF TEXAS. In November, 1845, a special board of engineer officers was appointed to examine the coast of Texas in relation to its defence. Their report, submitted in February, 1846, was to the following effect: The coast from the Sabine to the Rio Grande is about three hundred and seventy-five miles in extent. It is composed, for nearly the whole distance, of long narrow islands and peninsulas, which lie parallel to the main land, forming several bays and lagoons, the inlets to which exhibit channels generally only suitable to the smaller classes of vessels. Galveston bay is the most important one on the coast. Besides a number of bayous and small tributaries, it receives the waters of the river Trinity. This river is said to be navigable for six hundred miles for steamers of a light class, and, when improved, this navigation will doubtless be extended. The harbor is represented as being undoubtedly the best on the coast, the bar at the entrance having also the greatest depth of water. The charts submitted by that board show a depth of nine feet at low water and twelve feet at high water. A permanent work is proposed for the defence of this harbor, of the class of that constructed on Grande Terre island, Barrataria bay. Its estimated cost is three hundred thousand dollars.-(Class D.) The construction of some Martello towers along the shore and across the island is deemed essential to the defence of the "Swash" channel and to the security of the town, Brazos Santiago. The board deem this harbor of equal importance with that of Galveston; it has not much capacity, but is the only one in the vicinity of the Rio Grande. The bay at the pass has eight feet water. The trade of the Rio Grande and of its dependent country passes overland thirty miles to Point Isabel, and from thence issues from the Brazos Santiago. The depth of water over the bar at the mouth of the Rio Grande being only four feet, admits the passage of very small vessels not suited to the purposes of commerce. With reference, then, to the trade of the Rio Grande and to a point from which military supplies could with the greatest facility be sent to the frontier, the defence of the Brazos Santiago is deemed by the board of equal importance with that of Galveston, and they recommend a permanent work, of the size, character, and cost of the one proposed for the latter place, estimated at three hundred thousand dollars.-(Class D.) Matagorda bay. It is deemed due to the extensive country washed by the rivers tributary to this bay, that its entrance should be defended. The difficulties, however, attending that entrance, and the navigation of the bay up to Matagorda and La Vacca, would seem to lessen, in a military point of view, the importance of its defence as compared with that of Galveston and the Brazos Santiago; but as a very good harbor for vessels drawing no more than eight feet of water is exhibited within the bay at Porto Cabello, and as it would afford convenient rendezvous for the light flotillas of an enemy, it is considered that a permanent work of secondary importance to those proposed for Galveston and the Brazos Santiago should be constructed for its defence. A small work, mounting some twenty-five guns, and estimated to cost $175,000, is accordingly proposed. (Class E.) The remaining inlets on the coast, either from the shallowness of the water, the comparatively little value of the harbors themselves, or the nature of the country immediately depending upon them, are deemed to require, at present, no other defence than that of a temporary character. They would depend upon the ultimate opening of a line of inland navigation, considered practicable between the Sabine and the Rio Grande; and the necessary work would be thrown up only in time of war. GENERAL SUMMARY. It may be of convenience to have here a summary of the principles contended for in the preceding remarks, and of the essential points contained therein. 1. Assuming that we may have wars with nations in possession of extensive naval means, we must consider ourselves likely to be attacked wherever there are objects tempting to an enemy, either from the spoil he might hope to gather, or the injury that through them he might hope to inflict. We must also consider that the power of the attack will be proportioned to the value of the object, and that, consequently, the means of defence should be of corresponding strength. 2. The mode of defence proper to our circumstances, as sustained by the consideration presented in the preceding remarks, and others of analogous nature, and as exemplified by the present, as well as by the former practice of all nations having an exposed seaboard, is believed to be a system of permanent fortifications, consisting of work adapted respectively in their power to the value of the object covered, and applied, in times of peace, severally, in an order of time also fixed by the relative importance of the objects. 3. It is just this mode of defence that has been, to a great extent, built up in this country since the war of 1812, and that should be carried to completion as rapidly as the means of the treasury will allow. The points that are most valuable are already, to a very important extent, covered by these defences. But among many points that are valuable, all are not equally so; while, for exam ple, New York has had much done for it, Baltimore has had little, and New Bedford-the third city in the Union for registered tonnage-almost nothing. More than four thousand heavy guns may, however, as has before been said, now be mounted for the defence of places which it was necessary first to guard, in permanent fortifications that are equal to any in the world, in their respective grades, and placed, moreover, in the most effective positions. These are in what are called in this report classes A and B, namely, old works repaired and new ones completed, or nearly so, at a total cost of $16,756,708. Then follows the class of works in progress, (class C,) of which the remaining expenditures are estimated at $5,028,194. And then the class D, next to be commenced, in which there is no work that can be dispensed with, as must be evident on consulting the list, page 92. The cost of class D is estimated at $4,083,000. Then follows the class E, next in importance, of which the estimated cost is $2,235,000. As to those in hand, all have received the approbation of the government and Congress, and not one of those comprised in any other class can be begun without the particular sanction of both. The last class, marked F, the most numerous of all, cannot be begun for many years, at any rate, and then only as the several positions shall, in the view of Congress, have risen to an adequate degree of importance. The estimate for that class is $11,829,000. 4. Though facility of communication with the interior of the country, by railroads, might be an advantage in all cases where an enemy might land and conduct operations for two, three, or more days, there are few such positions that now have, or are likely to have, the advantage of such communications. Generally, the points of the coast attained by railroads are not points at which the people are deficient in numbers, but where they most abound; and besides, the attacks to which the coast will be liable, will be almost universally sudden attacks-attacks without warning-attacks that must be settled, one way or the other, before relief could come, even by railroad, and to which railroads could not supply relief, even were there time-men not being wanted to resist these attacks, but heavy guns, whether afloat or ashore. The use of existing railroads, or of any railroad likely to be constructed, cannot, in general, therefore, affect materially a system of forts and batteries upon the sea-coast. There may be particular instances of partial benefit, but none is likely to occur wherein their use could justify the reduction of the power of fortifications otherwise necessary, much less the dispensing with such works altogether. 5. The application of steam to vessels-of-war is believed to act detrimentally to the defence of the sea-coast by opening new avenues of approach, and also by the suddenness and surprise with which attacks may fall upon any point. The first augments the number of the defensive works, and the second requires them to be at all times-at the opening of the war as well as during its continuance-in a state of perfect readiness for action. With the large steam navies now kept in commission by naval powers, there would be no state of transition between peace and war-no time for new defences to be prepared, nor for substituting new expedients even if any such would answer. On the other hand, the use of steam vessels as a reliance for coast defence is attended with all the objections inherent in other modes of defence with vessels, and with some of the objections exaggerated. The objections that are inevitable are, inordinate expense and the perishable nature of the preparation ; and to these are to be added uncertainty as to their proper state of readiness, and as to their sufficiency when ready. Steamers should in no case, therefore, take the place of shore batteries, when the use of the latter is not forbidden by |