( 23 ) 
IV.—Account of Experiments upon the Force of the Waves of the Atlantic and 
German Oceans. By Tuomas Stevenson, Civil-Engineer, Edinburgh. Com- 
municated by Davip STEVENSON, Esq. 
In forming designs of marine works, the engineer has always a difficulty in 
estimating the force of the waves with which he has tocontend. The information 
on such a matter, which is derived from local informants, who, although intelli- 
gent in the departments of trade which they follow, are, nevertheless, more or less 
prejudiced from being constantly on the spot, is not satisfactory ; and it has, there- 
fore, often occurred to me that it would be most desirable if the engineer could 
be enabled, to some extent at least, to disregard the prejudiced statements of others, 
and the vague impressions left by them on his own mind, and really to ascertain, 
by direct experiment, what force, expressed in pounds per square foot, the sea 
actually exerts upon the shores where his buildings are proposed to be erected. 
Notwithstanding the want of all direct experiments* on this subject, and the 
somewhat unpromising nature of such an enquiry, I was, nevertheless, induced to 
attempt the construction of an instrument to effect the desired end; and after 
several fruitless devices had been put to the test, I at length succeeded in forming 
one whose indications I hope to be able to shew are trustworthy. Before con- 
sidering the results obtained, however, I shall explain the construction of this 
simple self-registering instrument. 
The letters D EF D represent a cast-iron cylinder, which is firmly bolted at the 
projecting flanges G to the rock 
where the experiments are 
wanted. This cylinder has a OQ 
flange at DD. LL is a door, 5 peepee = 
which is opened when the obser- =e 
vation is to be read off. AA 
is of iron, and forms a circular 
plate or disc, on which the sea 
impinges. Fastened to the disc 
are four guide-rods BBBB. ee - 
These rods pass through a circu- er or or on oe ee ee ee ae 
lar plate C C (which is screwed 
down to the flange D D), and also through holes in the bottom EF. Within the 





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* Sir S. Brown has infleed stated, that at Brighton he found the impetus of the waves during 
heavy gales was “ equal to 80 lb. to a foot upon a cylindrical column of 12 inches diameter.” The 
hydrostatical pressure of a wave only 11 foot high is equal to 80 lb. upon a square foot. 
