292 Mr, Seppings on a new principle of constructing 
by the hands at each end, which first bends, and then 
breaks. 
To prevent any transverse action upon the fibre of the 
timber, is one of the benefits arising from the new system, and 
to impede a longitudinal extension of the structure, is another. 
For as the diagonal frame, composed of a series of triangles, 
aided by diagonal trussing between the ports, prevents the 
fabric from being acted upon transversely to the fibres of 
the materials horizontally placed, so the wales, the plank- 
ing, the shelf pieces, the improved waterways, and the decks 
systematically secured, become the tie beams of the struc- 
ture. In a word, the system of triangles is so constructed, in 
conjunction with the planking of the ship, as conjointly to 
possess that property of a triangle already explained, viz. that 
its figure is as unalterable as the compression or extension of 
the fibre of timber will admit it to be. 
The strength of the principle has hitherto been considered as 
applying to, or resisting an alteration of, the figure, by giving 
great stiffness. It is now to be taken in another point of view, 
that of rendering the strength of the fabric as general and 
united as possible. For let it be again observed, the strength 
of any body is but equal to that of its weakest part. 
In the new system, the openings between the ribs are filled 
in with slips of timber nearly to the height of the orlop, or 
lower tier of beams ; which being then caulked, and paid or 
pitched over, makes the frame from head to stern, and within 
a few feet of the greatest draught of water, one compact and 
water tight mass of timber ; so that were any of the outer 
planking of the bottom to be knocked off, the ship would not 
only still keep afloat, but would be secured from sinking. In 
