442 REPORT—1840. 
ous phenomena which the Committee had observed, so as to 
reconcile theory with experiment. ‘The Astronomer Royal, Mr. 
Green, and Professor Kelland, had all been engaged on the 
subject; and the two latter had published memoirs in the 
Transactions of Cambridge and Edinburgh, in which they had 
succeeded in obtaining from analysis many of the very singular 
results published in the former report of the Committee. There 
still, however, remained difficulties which they had not been 
able to conquer; but as Mr. Kelland was about to lay before 
the Section his own investigations, it had become unnecessary 
to include them in this report. 
The subject which had chiefly engaged the Committee 
during the last year, was the conclusion and discussion of ob- 
servations on the Tidal Wave of the Frith of Forth. This 
tidal wave presented some very singular features; and, for 
the purpose of determining its phenomena with accuracy, a 
standard line had been levelled with great accuracy, under 
the direction of Mr. James Aden, C.E., and observations 
made at a great number of stations, the rise and fall of the tide 
being observed every five minutes. In this channel were ob- 
served the singular phenomena of four tides, or two double 
tides, every day; and, on some occasions, six tides, or two 
triple tides were observed. ‘These had all been accurately 
laid down from the levels; and it appeared that the top of 
high water rose at Stirling to the height of sometimes as much 
as ten feet above the level of the tides at Leith. The tides 
were of this form: 
J A, a common Tide-Wave. 
D B, the Tide-Wave of Leith. 
C, the Tide-Wave of Alloa. 
D, Tide-Wave near Stirling. 
0 
Mr. Russell had formerly intimated his expectation that this 
second tide was the great southern tide-wave of the English 
>a a 
