312 
Dr. Young's Remarks on the 
instant when the ship is in a horizontal position, while, in 
more common cases, when the waves are narrower, the strain 
will be proportionally smaller and nearer to the extremity. 
Hence it appears that the strain produced by the action of the 
waves may very considerably exceed in magnitude the more 
permanent forces derived from the ordinary distribution of the 
weight and pressure, being, according to this statement, nearly 
three times as great ; so that when both strains cooperate, 
their sum may be equivalent to about 15,000 tons, acting on 
a lever of one foot, and their difference, in opposite circum- 
stances, to about 5000. There may possibly be cases in which 
the pressure of the waves produces a still greater effect than 
this ; it may also be observed, that the agitation accompanying 1 
it tends to make the fastenings give way much more readily, \ 
than they would do if an equal force were applied less abruptl}\ , 
At the same time, it is not probable that this strain ever \ 
becomes so great, as to make the former perfectly inconsi- ■ 
derable in comparison with it, especially if we take into account 
the uninterrupted continuance of its action : it appears there- 
fore to be highly proper that the provision made for counter- 
acting the causes of arching should be greater than for 
obviating the strain in the contrary direction : for example, 
that if the pieces of timber, intended for opposing them were, 
on account of the nature of their fastenings, or for any other 
reason, more capable of resisting compression than extension, 
they should be so placed as to act as shores rather than as ties : 
although it by no means follows, from the form which the ship 
assumes after once breaking, that the injury has been occa- 
sioned in the first instance by the immediate causes of arching : 
since, when the fastenings have been loosened by a force of 
