TRANSACTIONS OF THE SECTIONS. 
607 
of the subsoil;—chalk, sandstone, and clay respectively pre¬ 
dominating in each. The plants peculiar to each district ap¬ 
pear to be sufficiently numerous and characteristic to warrant 
the proposed division : but the observations have not hitherto 
been made to such an extent as to enable Professor Henslow 
to speak with entire confidence on the subject. To the state¬ 
ments in this communication were added lists of such plants as 
had been detected since the last edition of the Flora Cantabri - 
giensis, and of those which had apparently become extinct in 
the county, in consequence, principally, of the extensive drain¬ 
age of the fen districts. 
10. ARTS. 
On the State of Naval Architecture in Great Britain. By 
George Harvey, F.R.S. E. &c. 
The vast national importance of the subject of naval architec¬ 
ture, as well as its necessary though not enough considered de¬ 
pendence on mathematical principles, is strongly insisted on 
by the author of this communication; and the latter circum¬ 
stance in particular is illustrated by a reference both to the ac¬ 
tual state of the art of ship-building in Great Britain, and to 
the history of its progress in France and other countries. The 
remarkable deficiency of mathematical theory in the adjustment 
of the external forms of vessels, on which their sailing perform¬ 
ance so much depends, is contrasted with the extreme perfec¬ 
tion to which the internal carpentry of the vessels has been 
brought by Sir R. Seppings and others; and the probable 
benefit of the application of refined analysis to the various 
practical problems which ought to interest the ship-builder,— 
problems of capacity, of displacement, of stowage, of velocity, 
of pitching and rolling, of masting, of effect of sails, and of re¬ 
sistance of fluids,—is illustrated. The notorious differences in 
the performance of ships, as well as the extraordinary variety 
in their external forms, are stated by the author to be at pre¬ 
sent unaccounted for in British treatises on ship-building ; and 
he proposes the theory of these diversities of structure, and 
differences of effect, as a specific object of investigation, which, 
though embracing only a part of the subjects that demand rigo¬ 
rous mathematical inquiry, is capable of yielding immediate and 
valuable results in practice. The example of the French phi- 
