462 SEVENTH REPORT—1837. 
which is probably produced by the circumstance that it is the 
result of two waves (one behind the other). The corresponding 
wave at Liverpool is also given; it is also a compound of two 
waves, which coincide nearly in time. 
From a laborious discussion of these observations, it appears 
that the wave of high water travels 
From IX. to VIII. in 6 min. 14 miles. 80 mil ene 
From VIII. to VII. in 9 min. 6 wat TARCEED GE 
From VII.to VI. in 6 min. 3°75 miles. 20 mil 1 
Brom - -V1.,f0) esa in 18 min. 4°25 miles. fe pn at ere 
From V.to IV. in 19 min. 2:5 miles. 8-1 mil Be 
From IV.to ITI. in 18 min. 2°5 miles, f a so al 
From. sLLI. to. 2 “UE: in 15 min. 2°75 miles. 15 mil hour 
From II. to Ll in 7 min. 2°78 alee peg 
These results show that in the deep water being between 40 
and 60 fathoms, or between 240 and 360 feet deep, the wave 
travels at the enormous rate of 30 miles an hour; that on 
reaching water from 20 to 30 feet deep, the velocity is di- 
minished to 20 miles an hour; and from V. to II. where the 
river is wide, shelving, and shallow, the velocity of the tide 
wave is retarded to 8 miles an hour; while on ascending fur- 
ther up; where the banks nearly upright, and the contracted 
width give an increase of mean depth, the velocity has a cor- 
responding increase to 15 miles an hour. 
By examining the plans it will be apparent that we shall not 
err greatly if we assume the average depth of the river, from I. 
to III., at 15 feet. From ITI. to V. the river is wide and 
shallow, spreading over extensive banks, where there are not 2 
feet of water, for which we may be allowed to take a third part 
of the greatest as a mean depth, or about 5 feet. In the di- 
vision from V. to VII., both depth and breadth increase very 
rapidly to about 35 and 37 ; taking 25 feet as the mean depth, 
we have 
Velocities of the Tide- Mean depth. Velocity due 
wave as observed. to depth. 
80 miles an hour. 240—360 feet. G6O0—80 miles. 
20 miles an hour. 25 feet. 19-3 miles. 
8:1 miles an hour. 5 feet. 8-6 miles. 
15 miles an hour. 15 feet. 14-9 miles. 
The following are the results of the observations in regard to 
the time of high water :— 
At Cloch Light,—High Water is 9 Min. earlier than at Port Glasgow. 
Lazaretto-Point ..........-.06. A do. do. 
Cumbray Light-house ......... 15 do. do. 
Portteatuick yh pcped-tencdve pear {| do. do, 
