184 PHILOSOPHICAL TRANSACTIONS. [aNNO 1787. 



bored to, in 1747, by the above-mentioned Thomas Partridge. After boring in 

 the same kind of clay to the depth of 210 feet from the surface, it changes to a 

 lighter-coloured one, which continues about 6 inches, and then changes dark 

 again, and continues so to the depth of 342 feet from the surface, where is a bed 

 of shells and white coloured earth, about half an inch thick, and under it a light- 



to 



coloured earth like that at 210 feet from the surface, and under it a bed of dark- 

 coloured clay. After continuing in that clay to the depth of 444 feet from the 

 surface, George Naylor put down a tin pipe, 50 yards in length, and 24- inches 

 in diameter within, to prevent the gravel and stones from falling down and ob- 

 structing the rods ; but being too weak for that purpose, it separated into differ- 

 ent lengths, and entirely prevented his boring, so that he was obliged to get the 

 said pipes up again, which took him 48 days ; having got them up, and cleared 

 the hole pretty well, he left off" boring till he could procure some stronger 

 pipes. 



July, 1784, he put down 21 pipes of cast iron, each pipe being 24- inches in 

 diameter within, half an inch thick, and on an average 6 feet 1 inch in length ; 

 they were fixed together with boxes and screws, and with a piece of soft leather 

 between the top of each box and screw, to prevent them from breaking ; the 

 uppermost pipe is fastened to a plank, which lies on the top of the brick- work. 



At the distance of 44 7 feet from the surface there is a bed of dark-coloured 

 earth mixed with chalk and gravel, which continues to the depth of 449 feet 10 

 inches from the surface, where is a bed of dark-coloured earth without any chalk 

 and with very little gravel, which continues to the depth of 454 feet 7 inches from 

 the surface ; there it changes to a dark-coloured earth, mixed with chalk and 

 gravel, which continues to the depth of 456 feet 8 inches from the surface, and 

 then changes to a dark-coloured earth without any chalk, and with very little 

 gravel, which continues to the depth of 457 feet from the surface, and then 

 changes to a lighter colour ; and this continues to the depth of 462 feet and 4 

 inches from the surface, where it changes to a darker colour, and so continues to 

 the depth of 470 feet 3 inches from the surface. Here the ground changes to a 

 dark-coloured earth, mixed with chalk and gravel, which continues to the depth 

 of 470 feet 7 inches from the surface, where he came to a bed of stone, like rag- 

 stone, about 1 3 inches thick, which ground into powder with the wimble, and 

 mixed with the earth. Under this bed of stone is a dark-coloured earth, without 

 any chalk, and with but little gravel, which continues to the depth of 472 feet 

 from the surface, when it changes something lighter, and continues so about 2 

 inches, where the earth appears to be mixed with chalk and gravel, and con- 

 tinues so for about 1 inch, when it changes to a black silt, having a great deal of 

 light-coloured sand in it. 



Sept. 6, 1785, George Naylor broke one of the screws belonging to his rods 



