528 REPORT—1890. 
the initial level of the sand. Thus reduced to a 30-feet tide, the initial 
depth of the sand was 5 feet higher in C than in B. The experiments 
were run for about 16,030 tides and surveyed, then re-started, when the 
level of water in C fell owing to a leak in the scummer. 
This lowered the sand at the lower end of the estuary, and a partial 
survey was made, and then the experiment continued until both tanks 
had exceeded 30,000 tides. The results, as shown in the plans, are very 
much alike, considering the very considerable differences in the initial 
quantities of sand. Owing to the much higher level of the sand in D, 
the top of the V was much more silted up in the early part of the experi- 
ment, and the sandbanks were higher towards the bottom of the estuary. 
Otherwise both tanks show the same characteristics. 
The highest point of the contour low water in the generator is still at 
Section 15, while the highest point of the contour at high water in the 
generator is at Section 4, so that the distance between the highest points 
of these sections was still about 11 miles, while the banks at low water 
extended down to Section 26. 
Experiments IL, Tanks C and D, with Land Water, Plate XIT., June 17 
to July 8.—The conditions in these experiments were the same as in 
Experiments I., Tanks C and D, except that the scummer in D was altered, 
until the mean tide level was only ‘003 foot above the initial height of 
the sand, and in Tank A :002 foot above, while the rise of tide in A was 
slightly greater and that in B slightly less. 
Surveys were taken at about 16,000 and 82,000 tides respectively ; 
they are very similar, and the effects of the land water are, as before, to 
slightly raise the lower sand and lower the upper. At low water there 
was still water in the channels right up to the top of the estuary, and at 
high water there was what would correspond in a 30-foot tide with 10 or 
12 feet of water at the top in the low-water channels. 
28. Experiments in long V-shaped Estuaries with straight tidul Rivers 
extending up from the top of the V with and without Water in Tanks B, E", 
and F.—Tank E was formed by opening out the partition boards in Tank 
C at the end of the V to a distance of 4 inches. That portion of the V 
below Section 12 remained as in Tank C, the position of the partition 
boards not being altered. Ata section, 12'5, a small angle was formed, so 
that while the boards above thesection remained straight their ends stood 
apart 4 inches instead of closing up to forma V. Tank C was extended 
by a trough 19 feet long, in which partition walls were constructed con- 
tinuing the partitions in the lower portion up to a section, 38, above the 
zero in Tank C ; these were straight, vertical boards, the distance between 
them contracting from 4 inches at the lower end to 1 inch at the end of 
the river. $ 
Tank F’ was formed in a similar manner, except that the upper 
extension was bent through two sharp right angles so as to return along 
the side of the tank ; and subsequently Tank F was formed exactly similar 
to Tank E with half the dimensions. 
Experiment with Land Water, I. and IL, Tanks E and F’, Plates XTII.- 
XVIL, July 11 to July 31.—In Tank E the sand was laid to a depth of 
4 inches, the same as in C, from the upper end of the river, Section 38 
down to Section 28. The rise of tide was 0°140 foot, and the mean level 
of the tide abont ‘016 foot above the level of the sand. The period 
49 secs. and water 1 quart a minute, or 1/200 the tidal capacity per tide, 
was introduced at the upper end of the river. 
