GENERAL MONTHLY MEETING, Monday, Feb. 6, 1871. SIR HENRY HOLLAND, Bart. M.D. D.C.L. F.R.S. President, Henry Edward Colvile, Esq. Duncan Davidson, Esq. Warren William De la Rue, Esq. James N. Douglass, Esq. Mrs. Gibbs. Abraham Goodall, Esq. F.R.C.S. Alexander Macfarlan, Esq. Robert Turtle Pigott, Esq., F.R.G.S. Robert Sabine, Esq. Charles Southwell, Esq. Henry Stilwell, Esq. Mrs. Jacob Waley. were elected Members of the Royal Institution. The special thanks of the Members were returned for the following addition to "the Donation Fund for the Promotion of Experimental Researches":— The PRESENTS received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz.: FROM Academia Pontificia de' Nuovi Lincei, Roma-Anno XXIII. 4to. 1870. Allen, Peter, M.D. M.R.I. (the Author)-Lectures on Aural Catarrh. 16mo. 1871. Astronomical Society, Royal-Memoirs, Vols. XXXVII. XXXVIII. 4to. 1869–70. 1870. 1870. Solar Eclipse of Aug. 18, 1868. By Warren de La Rue, Ph.D. 8vo. 1870. Monthly Notices, Vol. XXX. No. 9, Vol. XXXI. Nos. 1, 2. Bavarian Academy of Sciences, Royal-Sitzungsberichte. 1870. II. Hefte 1, 2. 8vo. Berkley, George, Esq. M.R.I.-Experiments on Steel, by a Committee of Civil Engineers. fol. 1868-70. Bombay Branch of the Royal Asiatic Society-Journal, No. 26. 8vo. 1870. British Architects, Royal Institute of-Sessional Papers, 1870-1: No. 1-3. 4to. British Museum Trustees-Miscellaneous Inscriptions of Assyria. fol. 1870. Catalogue of Syriac MSS. 4to. 1870. Catalogue of Vases, Vol. II. 8vo. 1870. Catalogue of Dermaptera Saltatoria, Part 4. 8vo. 1870. Catalogue of Monkeys, Lemurs, and Fruit-eating Bats. 8vo. 1870. Channing, Rev. Wm. Henry, B.A.-Religions of China. (K 98). 8vo. 1870. Chemical Society-Journal for Dec. 1870, Jan. 1871. Svo. Comitato Geologico d'Italia-Bolletino, No. 9, 10. 8vo. Firenze, 1870. Day, George E., M.A. M.D. F.R.S. (the Author)-Chemistry in its Relations to Physiology and Medicine. 8vo. 1860. 8vo. Editors-Academy for Dec. 1870, Jan. 1871. 4to. Chemical News for Dec. 1870, Jan. 1871. 4to. Horological Journal for Dec. 1870, Jan. 1871. 8vo. Nature for Dec. 1870, Jan. 1871. 4to. Pharmaceutical Journal for Dec. 1870, Jan. 1871. 8vo. Franklin Institute-Journal, Nos. 536-539. 8vo. 1870. Geographical Society, Royal-Proceedings, Vol. XIV. No. 5. 8vo. Geological Institute, Imperial, Vienna-Jahrbuch, 1870. No. 2. 8vo. 1870. Grant, Charles, Esq. (the Author) through the Lord Josceline Percy, M.R.I.— Gazetteer of the Central Provinces of India. 2nd edition. 8vo. 1870. Institution of Civil Engineers-Supplement to the Catalogue of the Library. 8vo. 1870. Jones, Henry Bence, M.D. F.R.S. Sec. R.I.-Speech on the German War, delivered Aug. 3, by E. Du Bois Reymond. (K 98) 8vo. 1870. Linnean Society-Proceedings, Nov. 1870. 8vo. London Institution-Journal, Nos. 1, 2. 8vo. 1871. Lubbock, Sir John, Bart. M.P. F.R.S. M.R.I. (the Author)-Description of the Park Cwm Tumulus. (Ethno. Soc. Journ. Jan. 1871.) 1870. Lyon, Mrs. J. T.-Memoir of Dr. C. Collier. 16mo. Mechanical Engineers' Institution, Birmingham-Proceedings, Aug. 1870; Part II. and Nov. 1870. 8vo. Meteorological Office.-Quarterly Weather Report: II. April-June, 1869. 4to. 1870. Meteorological Society-Proceedings, No. 51. 8vo. 1871. Moxon & Co., Messrs.-Haydn Series: a Dictionary of Science. Edited by G. F. Rodwell. 8vo. 1871. Photographic Society-Journal, No. 221. 8vo. 1870. Preussische Akademie der Wissenschaften-Monatsberichte, June-Nov. 1870. 8vo. Royal Colonial Institute-Proceedings, Vol. I. 8vo. 1869. Royal Society of London – Proceedings, Nos. 123, 124. 8vo. 1870. Sächsische Gesellschaft der Wissenschaften, Königliche Abhandlungen. 4 parts. 8vo. 1870. Berichte. 5 parts. 1868-70. Scottish Society of Arts, Royal-Transactions, Vol. VIII. Part 2. 8vo. 1870. Svo. 1870. Symons, G. J. Esq. (the Author)-Symons' Monthly Meteorological Magazine, Dec. 1870, Jan. 1871. 8vo. Tomlinson, C. Esq. (the Editor)-Dr. W. A. Miller, Introduction to the Study of Inorganic Chemistry. 16mo. 1871. Twining, Henry, Esq. M.R.I (the Author)-Elements of Picturesque Scenery, Vol. III. Part 2. 8vo. 1870. Upsal Royal Society of Sciences-Nova Acta, Ser. III. Vol. VII. Fasc. 1, 2. 1869-70. 1870. Upsala Universitets Arsskrift, 1868, 1869, 1870. 3 vols. 8vo. 8vo. 1870. 4to. WEEKLY EVENING MEETING, Friday, February 10, 1871. SIR HENRY HOLLAND, Bart. M.D. D.C.L. F.R.S. President, E. J. REED, Esq. C.B. On some Fallacies connected with Ships and Guns. IN opening his discourse Mr. Reed stated that the fallacies connected with ships, to which he proposed to draw attention, grouped themselves chiefly about that question of stability which the loss of the 'Captain' has recently brought into so much prominence, and at once proceeded to explain the nature of statical stability and the modes of measuring it. In its simplest form the stability of a ship might be considered as the result of the total weight of the ship acting downwards through her centre of gravity, and of her total buoyancy (equal to the weight) acting upwards through a centre situated at a short horizontal distance from it, this distance defining the leverage with which either force acted about the other. The weight of the ship being the same whatever the inclination might be, the distance in question, viewed as a lever, or, in other words, the length of the lever, might be regarded as itself indicating the degree of "righting force" which the ship possessed. The actual lengths of these levers were given by Mr. Reed for the 'Captain' for all degrees of inclination at intervals of 7 degrees, and were as follows: It will here be seen that the length of the righting lever, which Mr. Reed spoke of as the "Arm of Safety" of the ship, increased up to 21 degrees of inclination, and then began to decrease, the cause of this being next explained, and shown to result solely from the lowness of the freeboard. All the time the ship had bulk to immerse on the depressed side the buoyancy went on increasing on that side, and the lever in question lengthened. When she had no more side to immerse, but was still inclined farther by the wind, the ship began to sink lower in the water, and re-immerse the opposite side, and consequently the buoyancy was gradually transferred back to that side, the lever meanwhile shortening, and the power of the ship to resist the wind diminishing. The "Arm of Safety" consequently never reached a greater length than 101 inches, became only 5 inches at 42 degrees, and disappeared at 54. This state of things was then compared with that of the Monarch. The lengths of the corresponding levers in her were given as below: In this ship, therefore, the "Arm of Safety," which is rather less than the Captain's' at small angles of inclination, instead of shortening like hers when only 10 inches, goes on lengthening to very nearly double that amount, attaining its maximum only at about 40 degrees, where the Captain's' leverage was rapidly disappearing; and there the Monarch' possessed double the greatest amount of stability which the 'Captain' ever possessed. Mr. Reed remarked that these figures fulfilled the double purpose of showing that the two ships were remarkably alike in stability all the time the low freeboard did not interfere; but as soon as that began to play its part, the resemblance between them ceased altogether. He next proceeded to show the unfitness of the low-sided ship to have her stability substantially corrected by ballast, although a high-sided ship could readily have a deficiency of stability made good by these means. In illustrating this, he compared the stability of the 'Captain,' with 400 tons of water-ballast admitted into her double bottom, with that of the "Vanguard' class, with their iron ballast, as now equipped-about 360 tons in amount. The introduction of the 'Captain's' ballast so far improved her as to lengthen her "Arm of Safety" by a small amount at all degrees of inclination, but it left the general character of her curve of stability unaltered. In the case of the Vanguard,' on the other hand, her leverage of safety went on increasing up to great angles, becoming greater even than the Monarch's,' and presenting the very opposite condition to that of the 'Captain.' In all the aspects of statical stability the 'Captain' therefore stood alone, and bears no analogy or relation whatever to either the Monarch' or the broadside ironclads. Mr. Reed next explained by what means the stability of ships is increased, and stated that such an arrangement of weights might be made as to lower the centre of gravity and give to a ship of the Captain's' type a greater degree of safety than she possessed, but that it was not possible without exact calculations, based on specific designs, to say how low in freeboard it would be safe to go with a given spread of canvas. He incidentally remarked that as a matter of fact the Captain's' centre of gravity was much lower than that of several ironclads, giving the following figures: 6 1.99 Minotaur,' distance of centre of gravity below load water line 'Valiant,' Achilles,' 'Captain,' 1.51 It might, nevertheless, have been placed lower if the necessity for doing so had been foreseen. On the other hand, changes involving a raising up of great weights would have been essential in a new ship of the type, because on the eve of the loss, Captain Coles admitted to the Commander-in-Chief that the guns and turrets of the ship were much too low. Mr. Reed next explained the nature of dynamical stability, and how it was measured, and discussed the effects first of a rising wind, and then of gusts and squalls, upon ships under canvas. He showed that when inclined to 14 degrees the Monarch' had dynamical stability remaining to enable her to resist a squall of sufficient force, if continued, to hold her over to an angle of 20 degrees or more, and even then to have a large reserve of stability still in store. The 'Captain,' on the other hand, was without any such reserve, and would necessarily roll over under such a squall. Exact calculations only could show what reserve of force a ship had, and all these calculations affecting the 'Captain' have been made from drawings of the ship as built since her loss. The necessity for them was not foreseen in the proper quarter. This portion of the lecture concluded with a brief discussion of the effect of waves upon ships sailing under canvas, and of the extreme difference between such ships when with sails and without, showing how little doubt the 'Captain's' loss need cast on the unmasted monitors of the navy. Another fallacy which also related to the question of stability, but which the speaker considered extremely unscientific, and almost puerile, is that which attributes certain danger to the existence in a ship of a double-bottom divided into watertight cells or compartments. Gentlemen, whose names and whose very professions he refrained from mentioning, had published papers in which the doctrine is laid down that a cellular bottom is radically and necessarily dangerous; and, unhappily, such writings have in these days an influence which every man of science must deplore. It is difficult to treat such opinions with any respect, but the speaker endeavoured, in a few sentences, to illustrate their irrationality. He thought the best way to proceed was to assume that the logical way of remedying any evil which may attend the presence of two bottoms will be to remove one of them. He first supposed the inner bottom of the 'Captain' to have been removed, and inquired what effect this would have upon the ship. To his mind the effect was obvious. This inner bottom being substantially constructed of iron, is of very considerable weight, and the removal of this weight from the very bottom of the ship would have had the certain effect of raising the centre of gravity, diminishing the stability, and capsizing the ship all the earlier. There cannot be a doubt on the question. If it should be said that by removing this bottom the means would have been afforded of placing the engines, boilers, and other weights lower down in the ship than they could be placed while the inner bottom existed, he would answer that this line of argument is based upon a total misapprehension. It assumes that the weights of the 'Captain' and other ironclads were |