WAVES OF THE ATLANTIC AND GERMAN OCEANS. 



31 



A more exposed point of the Skerryrore Rock was at this time chosen for 

 experiment ; and with the view of ascertaining the effect of the waves at different 

 heights upon the rock, two instruments were fixed, the one (No I.) several feet 

 lower, and ahout 40 feet seaward of the other (No. II.) It was observed, that 

 about half-flood the force of the waves was a good deal expended before they 

 reached the place where No. I. was placed, from there being so little water on 

 the rocks outside. Whereas when the tide was higher the waves were, from the 

 greater depth of water, not so much broken when they reached No. II. The re- 

 sults of the Marine Dynamometer shew generally about twice the force at No, II. 

 as at No. I. ; a result which shews how important it would be to ascertain the 

 relative forces of the waves at different levels upon our breakwaters and other 

 seaworks. 



