[26] A body which shortly afterwards joined with a kindred society in forming the “Institution of Engineers and Shipbuilders in Scotland,” hereafter noticed.
[27] Following the methods laid down in the Treatise on Shipbuilding, edited by Prof. Rankine, Mr John Inglis, Pointhouse, instituted calculations in 1873 of the longitudinal strains of two steamers built by his firm, the form of the waves being assumed trochoidal. The result of these calculations—which, under Mr Inglis’ directions, were got out by Mr G. L. Watson, subsequently distinguished as a yacht designer, and then in the employ of Messrs Inglis—appeared in the form of curves of hogging moments in Engineering for 1st May, 1874. Mr Inglis found that entering upon the work of calculation had a very decided effect in giving him clearer ideas of how distribution of weight and buoyancy affected the structure of a vessel.
[28] The substance of this paper is contained in a series of three articles on the Strength and Strains of Ships given in “Naval Science” (vol. i. and ii., 1872-3), a high-class journal ably edited by Sir E. J. Reed, but unfortunately abandoned after the fourth year of publication.
[29] It should be stated that under certain circumstances of lading and support the value assigned by Mr John for the maximum bending moment may be exceeded in merchant vessels, and that in some special classes of ships—particularly light-draught vessels in certain circumstances of lading and support—the sagging moment may prove of most consequence. Instances are indeed on record of light-draught vessels giving way completely under the excessive sagging strain brought upon them at sea.
[30] The Institution of Engineers and Shipbuilders in Scotland was formed in 1865 through the amalgamation of two separate bodies—“The Institution of Engineers in Scotland” and “The Scottish Shipbuilders’ Association.” The former of these was founded in 1857 and the latter in 1860, the same year in which “The Institution of Naval Architects” was established. The membership of the Institution at the present time numbers nearly seven hundred, and comprises honorary members, members, associates, and graduates: the latter being a special section of the Institution, designed to embrace students or apprentices in the profession, and fulfilling a very useful end. The various offices have long been filled by gentlemen more or less actively engaged in the practice of shipbuilding or of engineering on the Clyde, and the proceedings have assumed, on this account alone, a richer practical interest. Scientific subjects have also received their share of attention, and of the members taking the lead in this connection the names of Mr J. G. Lawrie and Mr Robert Mansel are worthy of special mention. Along with Mr Robert Duncan and Mr Lawrance Hill, these gentlemen have, from the foundation of the Institution, taken a specially warm interest in its prosperity, and have contributed not a little thereto by the numerous valuable papers they have brought before its meetings. The secretary of the Institution is Mr W. J. Millar, C.E., himself the author of numerous papers, and the editor of the Transactions.
[31] For interesting and reliable information on this head, as well as on other matters dealt with in this and the preceding chapter, see Sir E. J. Reed’s excellent treatise on “Shipbuilding in Iron and Steel.”
[32] This method of graphically representing tonnage output was applied for the first time by the author to the Clyde district from the figures supplied by the Glasgow Herald for each of the years since 1860, and appeared, with much of the descriptive matter now given, in the issue of that journal for March 4th of the present year.
[33] The following fragmentary returns have, through the kindness of a friend engaged in shipbuilding on the Tyne, been forwarded while those sheets were in the press. They have been gathered from occasional records in the local press, supplemented by personal knowledge, but may only be taken as approximate:—
| Year. | No. of Vessels. | Tons. | Year. | No. of Vessels. | Tons. |
| 1864 | 97 | 49,820 | 1868 | 86 | 45,390 |
| 1865 | 123 | 77,500 | 1869 | — | —— |
| 1866 | 110 | 51,800 | 1870 | 95 | 86,420 |
| 1867 | 81 | 34,080 | 1871 | — | —— |
[34] These instruments, and the others here noticed, are supplied in this country by Mr W. F. Stanley, the noted scientific instrument maker of Great Turnstile, Holborn, London. They are described in his treatise on “Mathematical Drawing Instruments,” from which work, it should be stated, some of the present notes concerning them are derived. A source of accurate information on the theory of planimeter, to which Mr Stanley himself expresses indebtedness, is the paper by Mr —now Sir—F. J. Bramwell, read before the British Association in 1872, and contained in the Association Reports for that year.