446 SEVENTH REPORT—1837. 
Does their velocity depend on the depth of the fluid? Is their 
form cycloidal? What is the cause of their breaking on the 
shore? And what law is observed in their breaking? Why do 
waves in any circumstances break ? What is a breaker? These 
are some of the questions which the Committee have examined, 
and their results are of importance to theory and to navigation. 
The Committee obtained for the purpose of their observations 
on the waves of the sea the use of one of the yachts of the Royal 
Northern Yacht Squadron, which was kindly granted by her 
proprietor, James Bogle, Jun., Esq., at the request of the secre- 
tary. The Mermaid was an excellent sea vessel, but the weather 
was unfortunate ; she was alternately,becalmed and bestormed ; 
one day driven into harbour for refuge and the next day pre- 
vented by calms from leaving harbour. Out of eight days oc- 
cupied in this way not more than one was favourable to obser- 
vation. By subsequently crossing the Irish Channel in steam- 
vessels one or two observations of a sufficiently accurate nature 
were obtained. 
From these observations it appears to be established that the 
velocity of the waves at the surface of the deep water is not a 
direct function of the depth. 
In a depth of 50 to 60 fathoms the velocity was 13°5 miles an hour. 
In a depth of 53 fathoms the velocity observed was 20 miles an hour. 
In a depth of 60 to 70 fathoms the velocity was 17 miles an hour. 
In a depth of 34 to 40 fathoms the velocity was 17% miles an hour. 
In a depth of 51 fathoms the waves produced by a steam 
vessel passing at the distance of about a mile, moved at the 
rate of only 4°3 feet in a second. 
It thus appears that the waves produced by the wind on the 
surface of the deep sea do not follow the same law with the 
great wave of the fluid. In other words they are not primary 
but secondary waves, or waves of some inferior order. They 
do not move with the velocity due to half the depth of the fluid 
in which they are generated. 
The following are the most important and accurate observa- 
vations made on this subject. 
Observations.—The observations were made by bringing the 
vessel nearly to rest in a direction at right angles to the ridge 
of the wave. The cork fenders of the vessel were then attached 
at equal distances to the log-line, and spaces of 200 feet were 
marked off upon it. The time was taken by a common chrono- 
meter; the observations made were upon the transits of the top 
of the wave under the floating buoys attached to the log-line. 
1. 4th Oct. 1836, lat. 55° 38’ N., long, 4° 49’ W. 
Oif the Cambray Islands, 60 to 70 fathoms. 
Space 200 feet, time 7 sec, to 9sec. = 25 feet per sec. 
= 17 miles an hour. 
