ON TIE ACTION OF WAVES AND CURRENTS. ous 
ARTICLE PAGE 
21. Automatic tide gauges . - 4 ; . A : 521 
22. Compound harmonic tide curves . : : ‘ : : : : ee 
SEcTION IV.—Description of the experiments. 
23. Continuation of Experiments VII. Tank A,and III. Tank Bs. 523 
24, Experiments to find the limits of similar action, VIII. and IX. A, 
BV). Vill Boer . 524 
25. Experiments in rectangular tanks with land water, X. JN sh) VIII. B 525 
26. Experiments in short "Vs shaped estuaries without and with land water, 
XI. and XII. A,and X—XII.B . ° 526 
27. Experiments in long V-shaped estuaries without and with land water, i 
and II.C,andI.and1II.D . 527 
28 Experiments in long V-shaped estuaries with a tidal river, ‘with land 
water, I. E, and ii FandF’. 528 
29. The gradual diminution in the rise of tide owing to the lowering of the 
sand : 530 
30. Long V-shaped estuaries with a tidal river » ‘ithout land water, II. E, 
and II. F c : : : . : : : : : : . 531 
TABLE I.— General conditions and results of the experiments . 532 
»  IL—Mean slopes in the pe, V.to X. A, and ITT. to VII. B, 
in rectangular tanks , ? 534 
PLATES. 
I. Tanks and appliances. 
II. Reduced slope from Table II. 
IIJ._XVII. Plans and sections of the experiments. 
XVIII. Tide curves. 
§ I.—Inrropuction. 
1. In accordance with the suggestion in the report read at the 
Neweastle-upon-Tyne meeting of the British Association, 1889, the in- 
vestigation has been continued with a view (1) to complete the first 
series of experiments by determining the smallest vertical exaggeration 
at which similar results can be obtained with tides ranging upwards 
from half an inch in rectangular estuaries, and so to determine the law 
of the limits; (2) to determine how far similar effects can be obtained 
with land water acting on such slopes as had been already obtained in 
rectangular estuaries; and (3) to investigate the character and similarity 
of the results which may be obtained with V-shaped estuaries. 
2. The two models, subject to such modifications as were required 
for the various experiments, have been continuously occupied in this 
investigation, running, driven by the water motor, at all times when 
they were not stopped for surveying or arranging a fresh experiment. 
They have thus run about five-sixths of the time day and night. In this 
way the large model has worked through in the twelve months 500,000 
tides, corresponding to 700 years. These tides have been distributed 
over ten experiments or numbers from 32,000 to 100,000. The smaller 
model has run more tides than the larger, and these have been distributed 
over fourteen experiments. 
3. The experiments have all been conducted on the same system 
as is described in last year’s report. 
Initially, with two exceptions, the sand has been laid with its surface 
as nearly as possible horizontal at the level of half-tide, extending from 
the head of the estuary to Section 18, and in the later experiments to 
ean 1 The vertical sand gauges, ‘distributed along the middle line 
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