BRIGHTON WATERWORKS. 397 



in a direction parallel to the sea, and at about the level of low water, these 

 fissures would bo cut across and the water intercepted and stored in the tun- 

 nels. His conclusions were amply verified. Ramsgate has been supplied 

 since the year 1836 from wells and tunnels made on this principle. 



The town of Brighton is very similarly situated. For at least 6 miles to 

 the north, as many to the west, and nearly 8 miles to the eastward, there is 

 a succession of Chalk Downs untraversed by any river or stream. The geo- 

 logical formation is that of the Upper Chalk with flints. Throughout the 

 whole of this district (with a few exceptions of no importance) there is no 

 system of agricultural drainage : none is required. The whole of the rain- 

 fall, except that absorbed by the vegetation or given off by evaporation, per- 

 colates at once into the chalk, and has its chief outlet in the sea as before 

 described, — its chief outlet, because all round the base of the great escarp- 

 ment at the northern boundary of the Chalk Downs there flow out springs 

 more or less copious, which are formed by the overflow of the great chalk 

 reservoir when saturation has taken place. 8uch springs, for instance, are 

 those at Poynings, at Plumpton, and at Clayton. They find their way into 

 the sea by the river Adur at Shoreham on the west, and the Ouse at Ifew- 

 haven on the cast. The volume of these springs, however, is but a very 

 small percentage of the total quantity of rainfall, the main body of which is 

 absorbed by the chalk, and by its means travels to the sea. But although 

 the chalk is as absorbent as a sponge, it is equally unready to give up its 

 contents ; and, consequently, were it not for some outlet more free and open 

 than those afforded by its own pores it would necessarily overflow, and the 

 ordinary phenomena of surface-streams would result. These freer outlets 

 are provided in the shape of clefts or fissures extending almost from the 

 surface downwards to a very great depth, which have been formed in all pro- 

 bability, in the first instance, and continually kept open, by the action of the 

 water through a vast series of years. Where the stratification of the chalk 

 has not been disturbed by local upheavals and depressions, these fis§ures are 

 almost invariably at right angles to the coast-line : each is entirely inde- 

 pendent of its neighbour, and forms in itself a small rivulet, which takes its 

 origin from the supersaturation of the chalk, and flows down collecting water 

 as it goes, and finally discharges itself into the sea. The sides of these 

 fissures are generally of the colour of mahoganj'-, caused by the infiltration of 

 small particles of the upper clays, and are polished by the continuous friction 

 of the water. The fissures vary in size, but are seldom more than a few 

 inches in width, and generally not more than -2- of an inch ; thei'e is there- 

 fore considerable resistance to the passage of the water, and consequently as 

 the body of the chalk gets full the pressure keeps on increasing, as shown by 

 the varying level of the water in the wells. The diagram on the wall shows 

 the quantity of rainfall of each month for the 10 years 1862 to 1872, and 

 also the fluctuations of the level of the water in the ,wells on the Lewes 

 E-oad. This latter varies, as will be seen, from as low as 5 feet in depth in 

 the autumn of the year 1864 to as much as 88 feet in depth in the spring of 

 the year 1866. Speaking generally, the maximum quantit}' of water in the 

 chalk is in March each year, and the minimum in October to December ; and 

 the curve formed by the depths of the water follows that of the quantity of 

 rain at an interval of four months, the highest jiart of the one curve being 

 nearly coincident with the lowest of the other. It follows tliat the chalk is 

 acting exactly as a storage reservoir, and is receiving the surplus rainfall of 

 the months of October, November, December, and January (when, in con- 

 sequence of the low temperature and the comparative sluggishness of vege- 



