680 Boring Operations in Fort William. [No. 103. 



sunk by their own weight from 183 to 187 feet, and the bore could 

 now be worked to the depth of 189 feet. By the 10th November 

 following, a depth of 238 feet 5 inches had been attained, the chief 

 difficulty in prosecuting the work arising from the imperfect action 

 of the instrument employed in raising the sand, in consequence of 

 which the whole contents of the shell were frequently removed during 

 its passage to the surface. To the construction of the valves of such 

 instruments, much attention ought therefore to be paid, as on the effec- 

 tive action of these, the progress of the operations is most essentially 

 dependant. 



On the 15th November, an attempt was made to bring up some 

 water from the bottom of the bore by lowering a bottle with a large 

 brass plummet attached to it, to cause it to sink ; but unfortunately 

 before it could be raised, the connecting string broke, and the plum- 

 met was left below. Considerable anxiety was excited by this, from 

 the anticipation (subsequently realized) of the auger coming in con- 

 tact with the plummet, and being jammed within the tubing. On 

 arriving at the depth of 271 feet, the lower part of the.mudshell, in- 

 cluding the valve, from some unknown cause broke off, and remained 

 at the bottom of the bore. This accident caused much trouble, but 

 after various attempts to extricate the fractured shell, the perforation 

 of an aperture in it, by the use of a jumper, admitted of a strong 

 conical worm auger being screwed into it, and by the hold thus 

 obtained, it was successfully raised to the surface. 



At the depth of 324 feet the borer came in contact with the 

 long lost plummet, and became so firmly jammed between it and the 

 tubing as to foil every effort made for its extrication, though the 

 force applied at one time was so great as to raise the whole body 

 of the tubing about 4 inches, the weight of this being certainly not 

 less than 7i tons, exclusive of friction. To guard against the in- 

 convenience of an accidental fracture of the rods at any considerable 

 distance beneath the surface, while they were subject to such strains, 

 Captain Thomson of the Engineers suggested that the uppermost rod 

 should be made thinner and weaker than those within the bore (so 

 as to give way first) but yet capable of bearing a strain of 25 tons. 

 The force subsequently applied caused the rods however to break at 

 their connection with the mudshell, and though they were all brought 



