Ships of War by the application of Diagonal Braces. 5 
“ have done, from three to four inches, and which she ac- 
“ tually and immediately did on their being disengaged.” 
This statement of the Portsmouth officers, I trust, will be 
considered conclusive as to the benefits to be derived from 
the principle of trussing in the construction of ships ; and 
although it was only applied from the keelson to the beams 
in the hold, and not to the ribs or frame of the ship, as is the 
case when ships are regularly built on this system, yet it 
sufficiently establishes the soundness of the principle. 
When the Justitia first floated, after being partially trussed 
as described, the noise occasioned by the pressure on the 
trusses is stated to have been “ truly terrific,” until she was 
fairly settled on them. The disengaging them also caused 
a similar crash. 
As, previous to the abovemen tioned trial on the Justitia, 
some professional persons had expressed a doubt, whether 
the braces ought not to have been placed in the direction of 
the trusses, and vice versa ; the following experiment was ex- 
hibited to show what was expected to take place, and which 
did actually take place on the trial made upon the ship. 
Let No. 2 . Plate I. represent a frame of wood, having 
the braces B pinned to the upper and lower ties C ; let the 
trusses D and the longitudinal pieces E, be merely let in 
without any fastenings; then make the point F the fulcrum, 
and pressing down the ends GG, it will be found that the 
frame comes more in contact by the pressure. Next reverse 
the frame, and let H become the fulcrum, and by pressing 
at 1,1, it will be seen that the trusses D and the longitudinal 
pieces E will immediately be disengaged and fall out ; this 
proves that, had the long braces in the ships built on this 
