NARRATIVE OF THE SECOND AND THIRD EXPEDITIONS. 47 



boring purposes, in the absence of the tanks, we decided to abandon it, so we hauled 

 in the ropes and anchors, and allowed it to drift on to the lee shore of the reef near 

 Tebuka, where it was quickly broken to pieces by the waves. 



Although this attempt at boring the bottom of the lagoon failed, it paved the way 

 for the expedition later under Mr. G. H. Halligan, in H.M.S. " Porpoise," Captain 

 F. C D. Stuhdee, R.N. The very successful boring of the floor of the lagoon by 

 Captain Sturdee and Mr. Halligan in 1898 is described in another part of this volume. 

 For the rest of our stay at the atoll, Messrs. Sweet, Poole, Woolnough and I 

 employed oin^ time chiefly in dredging and chopping the reef-rock (between levels of 

 20 fathoms and 200 fathoms) on the ocean slope of the reef, and in making a 

 geological survey of the atoll. The latter part of this work was accomplished chiefly 

 by Mr. G. Sweet after I left the atoll. Our dredging and geological work is detailed 

 in separate reports in this volume. 



We may now return to consider the progress made at the main bore. By July 5th 

 the diamond drill was down 58 feet. On July 10th, when a depth of 62 feet had 

 been attained, a serious accident happened to the diamond drill. The large under- 

 reamer was being used at the time. The lower part, through friction in the silt, 

 became twisted and torn completely off" the upper part, and under-reaming being 

 continued for a short time after the accident had happened before it was noticed that 

 anything was wrong, the broken piece became jammed obliquely across the bore-hole. 

 All attempts at recovering the broken half failed for some time. A die was then 

 prepared and its under surface was armed with 'a mixture of beeswax, resin, and 

 tallow. A pipe was fixed in the centre of this apparatus so as to wash away the silt, 

 while the die was being lowered in the bore-hole. A cast having been obtained by 

 this means of the exact shajje of the part of the broken fragment which lay 

 uppermost, one of the tapering screw taps was specially modified so as to fit into the ■ 

 broken under-reamer and great efforts were made to recover it, but all to no purpose.* 



The forenian-in-charge told me that it was useless to try fishing any more for the 

 broken under-reamer, and that the only thing to be done v>^as to shift the drill to a 



* This accident was due to a defective design in the under-reamer. Instead of jetting water from the 

 very bottom, it was so constructed that the water was jetted from the openings through which the under- 

 reaming "dogs " were swung out. These openings were about a foot above the lower end of the under- 

 reamer, consequently as it was generally necessarj' to force the under-reamer down, in the process of 

 under-reaming through silt (which kept flowing into the bore-hole at the bottom and sides of the bore) 

 while the upper part of the under-reamer would be working freely — the silt having been washed away 

 from aroimd it by the hydraulic water-jets escaping from the slots in which the " dogs " were hinged — the 

 lower part would be grinding heavily in the silt. At last the torsion became so great that the lower half 

 was twisted off from the upper, causing the serious delay mentioned above. Mr. Garland, the mechanic 

 of our party, much improved the remaining under-reamer, after the above accident, by fixing a strong iron 

 pipe right through it, so that the water was jetted entirely from below the under-reamer, instead of frojii 

 the " dog " slots. 



The absolute necessity for having all tools to be used in boring or intended to reach the bottom of the 



