Submarine Mines in Relation to War. By Major G. S. Clarke, C. M. G., R. E. Woolwich: Printed at the Royal Artillery Institution, 1890.
Major Clarke in his concluding paragraph says: ". . . It had been sought to raise discussion upon the various points connected with the war uses of submarine mines, merely because such discussion is at present entirely wanting. All the other elements of defense, all questions of tactics by sea and land, have been subjected to searching and critical enquiry in endless books, pamphlets, and lectures. Nothing but good results from free discussion, by which alone can vagueness of thought and hallucination be swept away. The same method—the ordinary method of all science—must be applied to submarine mines, in order that they may be enabled to take their proper place in the Imperial Armoury. If an authoritative basis can be arrived at, they will fall at once into their legitimate sphere.” He adds that his opinions are those of a “non-expert.” Lawyers are held to be unfit jurymen, probably because their training is that of partisans, and in the consideration of legal technicalities they are apt to lose sight of the equity of the case. For the same reason it is well to have the opinion of a “non-expert” on the use of submarine mines, free from the bias begotten in the evolution of the mine-field.
Quoting from the Chatham Text-Book of 1873, Major Clarke says submarine mining defense is stated to be suitable for: (a) First-class fortresses, such as' Portsmouth; (b) Mercantile harbors, such as Liverpool; (c) Undefended harbors, such as Belfast; (d) Small harbors, such as Whitby; (e) Open towns, such as Brighton ; (f) Open beaches, such as Sandown.
The defense of open towns and open beaches against a fleet armed with long-range guns hardly needs serious consideration. To sow the sea with mines for the very ordinary radius, for bombardment, of 6000 yards, would be a serious task. As for an undefended harbor, that is, undefended by ships or guns, whether or not the mine-field is destroyed is simply a question of the disposition of the enemy.
In considering the case of defended harbors, the first question is as to the form of the port. If it is in the nature of a cul-de-sac, such as Plymouth, the inner harbor being commanded by guns, would any naval commander enter? Could even a battle-ship occupy herself in bombarding the town from such a position with her limited supply of ammunition, while batteries with a practically unlimited allowance were pounding away at her? It certainly is not likely that a naval commander would run into such a trap, even if cordially invited, and therefore mines would serve no purpose.
When the harbor is of such a shape that a fleet, once past the defenses of a narrow channel, finds itself in wide and safe waters, uncommanded by guns, and free to continue its operations, the use of mines is obvious, since every effort must be made to stop the passage of the enemy into the inner waters.
The time required for the construction and emplacement of modern heavy guns is so considerable that little can be done for the protection of a port, by guns, on the outbreak of war, unless they are already in position; and in such a case it may be protected from the entrance of an enemy’s fleet by mines for perhaps a few days, giving time for the arrival of a protecting fleet. The guns, once in position, arc always ready for instant use. The laying of a minefield takes considerable time and can never be commenced until war is at hand. Major Clarke considers it a valuable accessory in certain eases, but he protests against the absurdity of the pretension of the Chatham text-book and against the overgrown mine-field, with special batteries to cover it, a special flotilla to patrol it and special search-lights to illuminate it, the latter probably interfering seriously with the work of the main batteries in case of a night attack.
It is to be considered, moreover, that a really efficient mine protection involves the destruction of the commerce of the port. Merchant vessels will risk running a blockade, but will hesitate to attempt the narrow channel of a mine-field, if one is left, at night.
It is well for us in this country to bear the lesson in mind. We cannot allow the commerce of our ports to be destroyed; and for defense we must have heavy guns, commanding not only the entrance, but the harbor itself, where possible, a fleet of battle-ships to prevent a blockade, and clear channels for the entrance of friendly vessels.
C. S. Sperry,
Lieut.-Comdr. U. S. Navy.
Architecture Navale.—Théorie du Navire. Par J. Pollard et A. Dudebout, Ingénieurs de la Marine, Professcurs à l'École du Génie Maritime. Vol. I.
This work on Theoretical Naval Architecture, as contrasted with Shipbuilding, is by two of the lecturers at “l’École d’Application du Génie Maritime,” where the government students selected for the French Construction Corps take a course of two years.
Only the first volume has been received as yet; the remaining three arc, however, in press.
The subjects to be treated in the complete work are: Calculations of the geometrical elements and properties of ships’ forms, statical and dynamical stability, the rolling of ships in smooth and rough water, resistance and propulsion, the steering of ships, and the vibration of screw steamers.
Volume I. deals only with calculations of geometrical elements and properties, including methods and forms used in determining statical stability at given angles of inclination. Pp. 1-71 treat of methods used in calculation. The Trapezoidal and Simpson’s Rules are explained, and their absolute and relative accuracy discussed. Woolley’s Rule, the Method of Differences, graphic differentiation and integration, and mechanical integration arc also treated.
Pp. 72-114 arc devoted chiefly to the calculations found on an ordinary displacement sheet, dealing with the displacement in upright condition, and the corresponding positions of the center of buoyancy and the metacenters. In this portion of the work there is given, with full explanations, a complete copy of the regulation French tables and forms used in such calculations.
Pp. 115-252 discuss methods which deal with the ship when inclined, cither longitudinally or transversely. Under transverse inclinations, the authors explain five English and seven French methods of calculating transverse righting moments, and in addition, several methods of determining righting moments from models, etc.
The remainder of Vol. I, pp. 253-348, is devoted to the mechanics of floating bodies—including ships. All the elementary theorems of the subject appear to be here, and many which arc more interesting to the mathematician than to the average naval architect.
As may have been inferred from the preceding brief summary, this work collects and compares many methods which have been published separately in transactions of societies and in various technical journals. Hence, though containing matter of interest to all who have to do with ships, it will be of peculiar value to the naval architect as a work of reference.
The chief original matter in the present volume consists of comparisons between the various methods explained. These arc well drawn, and the distinctive advantages and disadvantages of each method are clearly and impartially pointed out.
A valuable feature of the present volume is a “Notice Historique et Bibliographique,” being a list of 468 books and papers—chiefly English and French —upon the various subjects covered by the present work. The books and papers arc classified according to dates and subjects, with short historical and critical notes upon the books.
D. W. Taylor,
Assistant Naval Constructor, U. S. N.
Hand-Book of Problems in Exterior Ballistics. Part I.—Direct Fire.
By Captain James M. Ingalls, 1st Artillery. Artillery School Press, 1890.
Captain Ingalls says in his introduction: “It is proposed to give practical solutions of all those problems of Exterior Ballistics which are likely to be useful to the artillerist, with examples fully worked out in the manner which a considerable experience has shown to be the most simple and concise.”
The intention has been well and fully carried out, and the book is an excellent guide for practical work. The formulas used are those of Siacci. Certain auxiliary formulas for the convenient approximate solution of certain cases have been added, and the subject of Probability is treated. The book includes Ballistic and convenient Auxiliary tables. C. S. S.