No 3] 



FARMERS' REGISTER. 



177 



four or five years, until the patience and the limils 

 of the parties were a!ii<e exhiuisted, but we tliink 

 enduirh has been staled above to prove to your 

 salisliicliun, liow very uncertain has been liiis 

 method of obtaining water. We think it right, 

 however, toiruard against theinipression that bor- 

 ing for water is ^i bad system; on the contrary, al- 

 low us to repeat that, we thitd< most, inghly of ii; 

 but then only under proper management, and as a 

 useful auxiliary to the sinking of capacious wells. 

 With respect to the project generally, of fbrm- 

 inii; a regular establishment tor the pur|)ose of sup- 

 plying water to the various towns of France, we 

 have to remark, that there can exist no i)hysical 

 impediment to the accomplishment of the plan; 

 there is no question but every town in France 

 miglit be made to enjoy the same inestimable ad- 

 vantages possessed by the inhabitants of London 

 and other towns of England; that is say, a con- 

 stant, abundant, and an economical supply of 

 good water, for all purposes of domestic and man- 

 ufacturing use; but of the three modes by which 

 this can be accomplished, the one by boring or 

 well-smking is decidedly the most expensive, and 

 the most uncertain in the final results. 



From the same. 



SOME ACCOUIVT OP SEVERAL SECTIONS 

 THROUGH THE PLASTIC CLAY FORMA- 

 TION IN THE VICINITY OF LONDON. 



By William Gravatt, F. R. S., M. Inst. C. E. 



Tring Hill Herts.. 



A boring for water for the Grand Junction Ca- 

 nal commenced at 25 feet below the summit level 

 of the hill near Marshcroft Bridge. 

 Chalk 20 feet. 



Hard blue 



clay 30 



Blue stone 4. At 54 feet the water rose 

 to the top and ran over 1360 

 cubic feet in 24 hours. 

 Hard blue 



clay 47 



101 feet — no more water than at 54 

 feet. 

 The boring discontinued in November, 1837. 



A second boring in the same hill commenced 

 20 feet from the summit level. 

 Chalk 30 feet. 



Hard blue 



clay 34 

 Blue stone 4. Water rose up. The stone 

 required punching before using 

 the auger. 

 Blue clay 82 fStrataof indurated clay at about 

 J every four feet, so hard as to 

 I require punching from (wo to 

 Black grit 10 (^ ten inches. 

 Blue clay 108 very hard. 



268 feet. Boring discontinued — no more 

 water than at first. These two 

 borings cost £145 and were 

 three months in hand. 



Norwood, near Standwell. 



A well four feet in diameter, sunk and bricked 

 280 feet through the blue clay, into the sand; the 

 Vol. V-23 



instant the sand was reached, the water nislied up 

 to the top so liist as to endanger the workmen; it 

 now stands wiihin 8 li'ct of thesurliice of the canal, 

 which is 86 feet above Trinity high water-mark. 



Boring at Brentford, six miles from London. 



Brick earth 8 feet. 

 Sandy gravel 7 



Ijoam 5 varies from one to nine feet. 



Sand and gra- 

 vel 4 varies from two to eiffht. 

 Contams water. 

 Blue clay 200 



224 feet. Boring discontinued — still 

 in clay. 



Woolwich Sandpits. 



Alluvium of various depths. 



Rolled flints with sand 12 feet. 



Clay, striped brown and 

 red, a few shells 6 water merely drops. 



Blue and brown clay, ma- 

 ny shells 9 



Iron shot sand, with ochre- 

 ous lumps 9 



Greenish sand, clean 8 



Greenish sand with flint 

 pebbles 1 



Light ash-colored sand, 

 perfectly clean 35 



Green sand, with green 

 chalk 1 



Chalk unknown, 



Plumstead Common. 



Shafts for Chalk. 



No. I. Alluvial gravel, and pure ash- 

 colored sand 120 feet. 

 Chalk penetrated to 24 



No water at 144 



No II. Alluvial gravel 36 



Stopped by the water. 

 No. III. At a small distance from this, stopped 



again by the water at the same depth. 



N. B. — These three shafts were in the same 

 field. 



Boston Heath, near IVoolwich. 



A well sunk for water. 



Gravel 65 feet. 



Sandy beds 65 



Chalk 70 



200 

 The water stands only five feet deep in this 

 well; a trifling supply of water was found in the 

 gravel. 



Lewisham loam pit kill. 



Alluvium various. 



Striped sand, yellow, fine, and iron shot 10 feet. 



