VI. MisceLLangous iwekisabinlas Y pina gem 
‘§ arts of the Atlantic and German came? be. a cearsaae 
(Trans. Roy. Soc. Edioburgh, xvi, 23.)—Mr. Stevenson’s experiments 
were made on the waves in the Irish Sea, the German Ocean, and the 
Atlantic at Skerryvore. To obtain results an instrument was con- 
trived, which he calls a Marine Dynamometer. It consists of a circular 
plate to receive the impinging wave, which acts upon a powerful steel 
spring enclosed in a cylinder ; and it is so arranged as to be self-regis- 
tering. The following are among the results obtained, with other ob- 
servations by Mr. Stevenson. 
In the Atlantic Ocean, according to the observations made at the 
Skerryvore rocks, the average of results for five of the summer months 
during the years 1848 and 1844, is 611 lbs. per square foot. The 
average results for six of the winter months (1843 and 1844) is 2086 
Ibs. per square foot, or thrice as great as in the summer months. 
__ The greatest result yet obtained at Skerryvore was during the heavy 
westerly gale of 29th March, 1845, when a pressure of 6083 lbs. per 
square foot was registered. The next highest is 5323 lbs. 
In the German Ocean, according to the observations made at the 
Bell Rock, the greatest result yet obtained is 3013 Ibs. per square foot. 
_ It thus appears, that the greatest effect of the sea, which has been 
observed, is that of the Atlantic at Skerryvore, which is nearly equal 
to three tons per square foot. 
_ These experiments, amounting to 267 in number, and on the Atlan- 
tic alone extending over 23 months continuously, are not intended to 
prove any thing farther than the simple fact, that the sea has been 
known to exert a force equivalent to a pressure of three tons per square 
- foot, however much more. Now, when .we.consider that the hydro- 
Slatie pressure due to a wave of 20 feet high, is no more than about 
half a ton on a square foot, we see how much of their force the waves 
owe to their velocity. There can be no doubt, however, that results 
higher than this will be obtained. 
I shall now contrast the indications of the Marine Dynamometer, by 
stating a few facts regarding the ascertained effect of the waves in the 
elevation of spray, and in the transportation of heavy masses of rock, 
is is more especially important, as to some, the results indicated by 
the instrument have appeared greater than they could have expected ; 
and it has even been supposed that, were they correct, the stones which 
itute our marine works would be scattered. 
Tn the Frith of Forth, at the Granton Pjer works, on 19th December, 
1836, afier a gale from the northeast, one stone was moved measuring 
