TRANSACTIONS OF THE SECTIONS. 181 
over 20 inches per annum. The late Mr. Robert Stephenson told me that upon 
one occasion in the Andes, the rainfall amounted to as much as 8 inches within the 
short space of an hour. This is a question assuming so great importance that I 
think this Association ought to use all its power and influence to induce the 
Government to aid it in these investigations, by which alone the engineer can 
be guided in the application of the laws to which I have alluded. I think that 
the quantity of water which falls alone the whole course of our rivers should be 
gauged, that the rainfall at different intervals should also be measured, and that 
there should likewise be meteorological observations, for the purpose of ascertain- 
ing the condition of the atmosphere under which these rainfalls occur. I think 
that if these observations were persevered in for a few years, a mass of facts might 
be collected which might, by the aid of the great and extensive knowledge of my 
friends now present, be applied to the permanent benefit of this country. 
The remarks I have just made may, to some extent, be illustrated by circum- 
stances connected with the rivers in this immediate neighbourhood. As you are 
aware, the rivers Wensum and Yare conyerge at a point a little below this city. 
The river Waveney joins them a little below Reedham, and the river Bure flows 
into them at a point not far from Yarmouth, the whole of the water being con- 
veyed thence through the harbour into the sea. There is no doubt that formerly 
there was in this locality a great estuary open to the ocean, but the travelling 
sands which form the dunes upon this coast seem to have confined that water 
within the narrow channel which falls into the ocean at Gorlestone. I believe 
that at one period the Waveney flowed through Mutford lock, and that a dam was 
erected there by the advice of some Dutch engineers, with a view to prevent the 
incursion of the sea, which doubtless inflicted upon the upper lands much greater 
injury than could be caused by the freshwater floods. But, be this as it may, if 
you trace the Wensum from its course down the valley, flowing at a gentle rate, and 
affording nourishment to a considerable tract of country between Norwich and Yar- 
mouth, you will find that the entire flow of the water is maintained by a fall of 
something like 4 or 5 inches in the mile. This circumstance is undoubtedly attended 
with great advantage to the neighbourhood. In the first place, the waters of the Yare 
are free from any large amount of deposit, while the velocity of the stream is so slight 
that it does not have the effect of destroying or injuring the banks, which are com- 
posed of a soft material, and the river being deep, enables a large amount of com- 
merce to be carried on between Yarmouth and Norwich by those beautiful craft, 
the wherries, which navigate these waters. Such is the facility afforded by the 
river for the conveyance of traffic, that these wherries maintain to this moment an 
active competition with the railway which runs between this place and Yarmouth. 
Near Yarmouth we have the entire body of water belonging to this district con- 
verging at the head of Breydon, and all the circumstances connected with these 
waters are subject to laws which we can estimate with perfect certainty. But 
beyond the point I have alluded to they come in contact with the tide; and here 
commences a disturbing element, upon which a great variety of opinion is main- 
tained, and which has, I am aware, led to much litigation. 
Yarmouth has also this further natural condition, that being surrounded by a 
yast amount of sand, which forms the roadstead, the result is that, although on 
both sides of the coast, at Aldborough and on the estuary near Lynn, the tide 
rises from 16 to 18 feet at springs, nevertheless it only rises some 5 feet at Yar- 
mouth. The consequence is that the tidal scour at Yarmouth is very much 
reduced, and the effect is so much modified that it occasions a large outlay in 
maintaining even the present depth of water over the bar, inadequate as that may be. 
But if the range of the tide through the port of Yarmouth had corresponded with that 
upon each side at the places I have mentioned, it is a question whether its effect 
upon the estuary of the river would not be of the most disastrous character. My 
own opinion is that such would be the effect ; but my more immediate object is to 
call attention to the tidal influences, combined with the fresh water from the land, 
in the maintenance of the bar at Yarmouth. Upon the question of how much is 
due to the land floods, and how much to the flux and reflux of the tide, there is 
great difference of opinion among philosophers and engineers. It is, indeed, a 
difficult question ; but I think it is one that ought to be grappled with, and one 
