138 
SIR G. B. AIRY ON THE TIDES AT MALTA. 
From — 
To— 
Interval in 
Time. 
Number 
of 
Waves. 
Mean 
Duration of 
One Wave. 
Largest 
Rise or 
Fall in the 
Group. 
d. h. m. 
d. h. m. 
h. m. 
m. 
inches. 
1872. June 9 6 10 
1872. June 9 13 15 
6 55 
18 
23 
2-2 
13 15 
20 45 
7 30 
20 
22-5 
1-7 
20 45 
10 4 10 
7 25 
19 
23-4 
6-4 
10 4 10 
12 10 
8 0 
20 
24 
5-0 
12 10 
20 15 
8 5 
19 
25-5 
6-8 
20 15 
11 4 10 
7 55 
20 
23-75 
7-8 
11 5 20 
10 15 
4 55 
14 
21-1 
8-2 
10 15 
17 10 
6 55 
19 
21-8 
4-2 
17 10 
21 10 
4 0 
12 
20 
2-1 
21 20 
12 1 20 
4 0 
12 
20 
2-8 
28 0 5 
28 6 55 
6 50 
18 
22-8 
1-5 
6 55 
14 35 
7 40 
20 
23 
0-9 
14 35 
20 15 
5 40 
19 
17-9 
0-9 
20 15 
29 0 45 
4 30 
12 
22-5 
1-5 
29 22 10 
23 45 
1 35 
4 
23-8 
1-2 
30 0 5 
30 4 10 
4 5 
10 
24-5 
1-8 
4 10 
11 45 
7 35 
L9 
23-9 
3-0 
11 45 
19 0 
7 15 
20 
21-75 
3-2 
19 0 
July 1 3 15 
8 15 
19 
26-1 
1-8 
July 1 3 15 
11 10 
7 55 
19 
25 
1-6 
11 10 
18 40 
7 30 
19 
23-7 
1-7 
18 40 
20 55 
2 15 
6 
22-5 
1-2 
6 5 10 
6 9 30 
4 20 
13 
20 
1-2 
9 30 
17 0 
7 30 
19 
23-7 
1-9 
17 0 
21 25 
4 25 
12 
22-1 
2-2 
21 40 
23 50 
2 10 
6 
21-7 
2-4 
7 0 10 
7 6 30 
6 20 
16 
23-75 
4-7 
30 0 10 
30 8 35 
8 25 
18 
28-1 
1-0 
8 35 
18 50 
10 15 
19 
32-4 
1-3 
19 10 
20 30 
1 20 
3 
26-7 
0-8 
August 28 21 30 
August 29 5 45 
8 15 
20 
24-75 
2-4 
29 5 45 
13 15 
7 30 
19 
23-7 
4-5 
13 15 
15 10 
1 55 
5 
23 
4-5 
Appendix. 
My first knowledge of the Seiches at Swansea was derived from a letter of 
J. W. G. Gutch, Esq., dated “Swansea, Feb. 18, 1838,” of which the following 
is an extract : — 
“ I have some very singular curves marked pay the self-registering tide-gauge] in 
last month, and should much like to hear your explanation of them. They appear 
thus [with a rough diagram], and generally the irregularities occur at the top of the 
tide, and apparently at intervals of about a quarter of an hour or twenty minutes ; 
they seem to be large tidal waves.” 
In my reply, dated February 27, 1838, I said : “The small irregularities of height 
which you mention puzzle me extremely. I do not see how they can come from the 
tides ; whether from any strange reflections of waves in the bay or across the channel 
I cannot tell.” — G. B. Airy, October 4, 1877. 
