ON WAVES. 457 
Fourth Series of Observations. 
On the Tide Wave of the River and Frith of Clyde in 
Scotlund.—The observations on the river Dee having been 
necessarily very limited in number, and in the means as well as 
objects of inquiry, suggested the nature and indicated the ne- 
cessity of a more extensive series of observations of the tide 
wave in its progress along some limited channel whose dimen- 
sions might be determined with the requisite precision. The 
river and frith of Clyde on the west coast of Scotland were at 
once suggested to the Committee, as in every way suitable to 
the objects of their inquiry. That river is, like the Dee, con- 
tained in a channel, which is a work of art rather than of 
nature, having been rendered one of the finest rivers in Britain 
by the perseverance, enterprise, and wealth of the citizens of 
the important manufacturing and commercial city, whose mer- 
chandise it transports from all quarters of the world. Your 
Committee made application, with the assistance of Sir Thomas 
Brisbane, the President of the Royal Society of Edinburgh, and 
one of the former presidents of the British Association, to the 
board of Commissioners or Trustees of the navigation of the 
Clyde, and were fortunate in obtaining their cordial and ‘ef- 
fectual co-operation in conducting all the observations and ob- 
taining all the information they required. The willing assistance 
of Mr. Logan the engineer of the river, was given in conducting 
the observations; at his request simultaneous observations were 
made at several other ports in the vicinity ; Captain Denham, 
R.N., of Liverpool, was good enough to order similar obser- 
vations at that port; Professor Nicol kindly placed the instru- 
ments in the college observatory at their disposal, for regulating 
the time-keepers of the observers, and nothing was omitted 
that could give the observations value and general interest. 
Moreover, it was fortunate that the board of Trustees had just 
obtained very accurate surveys of the river with transverse sec- 
tions, at distances of each quarter of a mile; and they further 
ordered that the stations of observation should be connected by 
a system of levelling. -These were all placed at the disposal of 
the Committee by the Trustees and their engineer, who were of 
opinion that observations of that nature were of equal value to 
the practical navigation and improvement of their river, as to 
the theoretical speculations of the British Association. 
Throughout the greater part of 18 miles, the distance be- 
tween Glasgow and Port-Glasgow, the river Clyde is little more 
than an inland tidal canal, excavated and embanked by artificial 
means; it then expands into a frith of considerable breadth, 
