THE RIVER BURE AND ITS TRIBUTARIES. 225 
The charts from Brundall and Oulton show well what is 
often indistinct in the records from the Bure, namely the 
difference in range between alternate tides, or the diurnal 
inequality. In the charts from Oulton the afternoon tide 
was always greater than the morning tide. The same thing 
may be traced in favourable conditions in the Bure, but since 
the range of the tide is so small, the difference between 
successive tides is liable to be obscured by any disturbing 
factor such as wind. Thus at Acle Bridge in July, 1906, the 
range of successive tides was : — 
Morning. Afternoon. 
Time. 
Range. 
Time. 
Range. 
2.0 
nf in. 
i-45 
13$ ’ n - 
2.30 
iof in. 
2.30 
i 3 f in. 
3-o 
9 in. 
— 
— 
The Progress of the Wave up the River. 
(a) The River Bure.* 
The progress of the wave may best be traced by showing 
the range of tide at different points in the river. The range 
of the tide is the rise from low water to high water of any given 
tide, and must be distinguished from the “ Rise,” which 
means the rise from mean low water of spring tides. As no 
fixed datum line is available I have been obliged to give 
in all cases the range only. This course has obvious dis- 
advantages in that it somewhat obscures the significance of 
the charts. Thus the range of two tides might be the same 
although a strong North wind might have held up the ebb 
to an unusual level, so that the second flood might have come 
in on the top of this and caused an exceptional rise. 
The range of the tide off Yarmouth is comparatively small, 
amounting to about 6 feet at springs and 4 feet at neaps, 
* Drainage area of the Bure and its tributaries, 337 square miles. 
Gradient of the Bure 1 in. 30,000 or about 2" in the mile. 
Average flow of river at Horning about 40,000,000 gallons per day. 
Q 2 
