THE RIVER BURE AND ITS TRIBUTARIES. 227 
of the moon. The period is not sufficiently long entirely 
to remove the effects of abnormal tides, but it is enough 
to show clearly the difference of range at the Bar and at 
Southtown Bridge. 
The following table gives further details of the tidal range 
at Southtown Bridge abstracted from the figures for 24 months 
(September, 1905 — June, 1906, and April, 1907, to May, 
1908). 
Average. 
Weekly Range. 
Extreme Range. 
Height on Gauge.* 
Springs. Neaps. 
Springs. Neaps. 
Springs. 
Neaps. 
4 ft. 7 in. 3 ft. 7 in. 
5 ft. 4 in. 2 ft. 7 in. 
6 ft. 3 in. 
4 ft. 4 in. 
At Muckfleet. 
The Muckfleet Dike, about 10 miles from Southtown Bridge, 
is about the extreme point at which salt water may normally 
be traced. Here records were taken of five tides on June 
7th — 8th, 1906, showing that the range, during normal spring 
tides, without apparent influence of wind, varied between 
14 and 16 inches. The form of the tidal curve is very well 
shown here (Fig. 1). 
A rather longer series of observations were taken at the 
same point from September 12th to 16th, 1910. The moon 
was at its first quarter on September nth, so that the period 
corresponded to one of increasing tides. 
The wind was North-easterly during the period, but of moder- 
ate strength, so that no disturbance of the tide should be looked 
for. Taking the range from low water to high water and 
from high water to low water of each successive tide there 
was a gradual, though rather intermittent, rise of range from 
6.9 in. to 9.3 in. The only notable exceptions were the tides 
of September 14th, when the range of low water at midnight 
on September 13th to low water at 1.30 p.m. on September 
14th was 10.9 in. and 10.2 in. I cannot account for this from 
the weather observed. There was heavy rain and a dead 
* Zero on the Yarmouth gauge is the average low water of spring 
tides, and is 1 ft. 9 in. below O.D. 
