TBASSACTIONS OF SECTION C. 547 



5. On the Southampton Artesian Well. By T. W. Shore, F.C.S., and 



E. Westlake, F.G.S. 



In bringing; forward this subject on behalf of the town, we place before the 

 Section such details as we hope may enable them to form aa opinion on a 

 question of much local importance, viz., whether it is possible, by an extension of 

 the existing well, to utilise it as a source of supply to the town. 



The amomit of water yielded by the well, on the last occasion of pumping, in 

 1851, was 130,000 gallons per day. The quantity at present supplied to the town 

 from the Itchen is from three to three and a-half million gallons, but this is a 

 much larger quantity per head than is foimd to be sufficient for towns under a 

 regulated system of supply. It thus appears that the well yields about one twenty- 

 fifth part of the quantity required. 



For the purpose of increasing the yield two methods are suggested. One of 

 these is, to drive galleries or drift-waj"s in the chalk. The other, to continue the 

 boring through the chalk into the upper and lower greensands. 



We will first describe the present condition of the well, and then refer to the 

 probable nature of the strata below the point reached by the boring. 



The work of excavation was carried on from July 1838 till February 1851, at a 

 total cost of 19,000/., and reached a total depth of 1,317 ft. 



A well was sunk by means of iron cylinders and brickwork, through 464 ft. of 

 the tertiary beds. The diameter is 13 ft. at the top, and diminishes by successive 

 stages to 7 ft. in the lower portion. 



The beds passed through consist of: 2 ft. of soil; 74 ft. of lower Bagshot 

 beds, consisting of sand and clay in alternations ; 304 ft. of London clay, consisting 

 of sandy clay, with seams of water-bearing sand, and pebble-beds towards the top ; 

 84 ft. of plastic clay, with the usual bed of greensand at the base. The chalk was 

 reached at a depth of 464 ft., where the masonry was terminated. The 7-ft. shaft 

 was continued 90 ft. in the chalk. A boring was then made with a six and a-half 

 inch auger to a further depth of 754 ft., making a total of 853 ft. in the chalk, or 

 1,317 from the surface. The chalk is stated to have contained Hints, all but the last 

 10 ft. The bottom 15 ft. of the tlinty chalk is described as blue and cloggy. The 

 last 10 ft. contained veins of clay, and were very cloggy. 



At this point the boring was stopped, the cost at that time being twice 

 as great as it is at present, and the report of ftlr. Hanger, the consulting 

 engineer, being unfavourable to its continuance. 



The moutli of the well is 140 ft. above the level of the sea, and the water stands 

 at present at 40 It. below the surface of the ground. 



Most of the water appears to come from the chalk. Previous to the commence- 

 ment of the boring in 1842, 20,000 gallons per day were raised ; in 1 844, after con- 

 siderable progress had been made in boring, this increased to 50,000 galkins ; 

 and finally, in September 1851, to 130,000 gallons. The chalk thus supplies about 

 five-sixths of the whole quantity. 



In connection with the method of increasing the yield of a chalk well by driving 

 galleries, we give a few particulars of the Brighton Waterworks, as an example of 

 the application of this method to the supply of a large town. 



Those who know the Brighton Downs will be aware that the rain forms no 

 •surface streams. It is entirely absorbed, and passes to the sea through fissures in 

 the body of the chalk. Since the chalk is as retentive as it is absorbent, it seems 

 probable that the drainage in chalk districts takes place almost entirely bj^ means 

 of these fissures. In the Brighton Works the fissures are found to follow tlie dip 

 of the beds. They vary in size, up to a few inches in width, but are generally not 

 more than tliree-fourths of an inch. The sides of these fissures are usually of the 

 colour of mahogany, caused by the infiltration of small particles of the upper clays, 

 and are polished by the continual friction of the water. 



The plan adopted at Brighton is to sink wells, and drive tunnels or adits at the 

 bottom of these wells in a direction parallel to the strike, so as to cut as many as 

 possible cf the fissures and intercept the water before flowing to the sea. In the 



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