496 



Since the luminous appearance of the Milky Way is caused by 

 stars that are invisible to the naked eye, this part of the heavens pre- 

 sents a vast field for observation on the existence of a clustering 

 power. To the naked eye it is visibly divided into large patches ; 

 and a telescope shows it to be still further subdivided into unequal 

 groups, which, though now not completely detached, it is presumed 

 will hereafter become insulated ; so that the Milky Way will finally 

 be broken up, and cease to be a stratum of clustered stars. 



The same mode of reasoning that leads the imagination to con- 

 ceive the progressive changes of its future existence, involves also 

 the supposition of its origin at some period certainly very remote, 

 but which it may possibly be in the power of future astronomers to 

 estimate, by means of accurate observations on the rate of those 

 changes that may be discovered to have taken place in the course of 

 ages yet to come. 



With respect, however, to the extent in space of that portion of 

 infinity through which any objects are discernible, and the arrange- 

 ment and relative distances of all celestial bodies yet observed, the 

 author is of opinion, that some present judgement may be formed ; 

 and he is now engaged in a series of observations, with a view to 

 investigate the visible extent of the universe. 



On a new principle of constructing His Majesty's Ships of War. By 

 Robert Seppings, Esq. one of the Surveyors of His Majesty's Navy. 

 Communicated by the Right Hon. Sir Joseph Banks, Bart. K.B. 

 P.R.S. Read March 10, 1814. [Phil. Trans. 1814, p. 285.] 



After remarking upon the length of time that has elapsed since 

 any considerable improvement has taken place in the art of ship- 

 building, and the causes that appear to have prevented amendments 

 being introduced, the author gives a general outline of the structure 

 of ships, as hitherto built, which he represents as consisting generally 

 of pieces of timber or plank, all placed nearly at right angles to each 

 other. For, first, the ribs rise at right angles to the keel. The ribs 

 are crossed, on their inner as well as outer side, with planks at right 

 angles to them, and parallel to the keel. And within the inner linings 

 are also a secondary series of ribs, called riders, at some distance from 

 each other, parallel to the former set, and at right angles to the keel. 

 Across this fabric are placed beams, connecting the opposite sides of 

 the vessel ; and these also are at right angles to all the parts before 

 mentioned. From beam to beam, at right angles, are the carlings, 

 which support joists parallel to the beams, on which are laid the 

 planks of the deck, in a right line from head to stern, and accord- 

 ingly preserving uniform adherence to the parallel^and rectangular 

 structure, which in every other instance of carpentry is known to 

 every common mechanic to be the weakest form in which any num. 

 her of lines can be framed together, as it affords no check to that 

 bending of the materials to which they are liable in the direction of 

 their greatest length. To this cause is to be ascribed the well-known 



