46 
MR. AIRY ON THE LAWS OF INDIVIDUAL TIDES 
feet. 
Below a mark on the coin stone at the south-west angle of All Saints’ 1 
Church J 
Below the flags of the footpath 
Below a mark on the north side of the pedestal which supports the east lion 4 
at the north side of the Bar J 
Below the ground there 
Below a mark in the bricks of the wall at the south-west side of the door 4 
of the toll-house, at the junction of the London and Salisbury roads . . J 
Below the ground there 
Below the lower sill of the centre door of St. Paul’s Church 
Below the flag-stones 
Below a mark on the south front of the west angle of the east wing of the } 
buildings at the Ordnance Map Office J 
Below the ground there 
43-057 
3/-657 
50-514 
45-094 
69-669 
67-219 
77-814 
76-704 
89-344 
87*449 
The height of the water upon this scale was observed at every five minutes, from 
February 23, 15 b 10 m (astronomical reckoning), to February 27, 6 h 20 m . The watch 
by which the times were taken was a pocket chronometer belonging to Lieutenant 
Yolland, of which the error was small. The observations at February 24, 6 h 5 m and 
6 h 10 in , were omitted from inadvertence (darkness coming on before proper prepara- 
tions were made) ; those of February 24, 6 h 35 m and 6 h 40 m , were excluded from cal- 
culation, because the water was disturbed by a boat ; and those of February 25, 2 h 0 m , 
2 h 5 m , and 2 h 10 m , because they were evidently irregular, although no reason was 
assigned for their irregularity. 
When the seven complete tides embraced by these observations were laid down in 
graphical projection, each of them presented a curve similar in its general form to 
the extraordinary figure represented in the diagram, fig. 1. in Plate II.; four of the 
curves having three maxima of elevation in each tide. In the first two tides, the first 
maximum, as in the diagram fig. 1, was rather a stand-still in the rise than a rise and 
fall ; and in the last tide (the highest of all), the first and third maxima were both of 
this character. In all the others, the three maxima to each tide were well marked. 
On February 24, from 15 h to 17 h , the wind blew strong from W. and S.W. On 
February 25, from 18 h to 19 h , it blew a gale from S.W. and W. From February 25, 
21 h , to February 26, 3 h , the wind was strong from S.W. and W. And from February 
26, 20 h to 23 h , there was a strong W.S.W. wind. At other times the air was almost 
perfectly calm. These changes in the state of the atmosphere do not appear to have 
produced any sensible alteration in the character of the individual tides. 
The epochs and magnitudes of the tides appear, however, to have been sensibly 
altered by these or other disturbing causes. Thus, if we examine the times and in- 
tervals of high water, they are as follows : — 
