262 Scientific Proceedings, Royal Dublin Society. 



about 1500 lbs., and, of course, be stranded and of galvanized steel. If serious 

 sticking of the drill in the mud is found to occur, the use of two concentric 

 tubes does not appear to present any difficulty. In this case the outer or 

 active drill-tube would be left behind in the mud, and only the inner tube 

 brought up. But I may point out that the effect of the longitudinal ribs on 

 the outside of the drill will be to loosen a surrounding part of the bottom 

 materials, and that in consequence we may expect that the drill will be easily 

 withdrawn under the influence of a steady pull. The best method of providing 

 such a steady pull from the surface will be mentioned later. 



It is very desirable to be able to follow the operation of the drill from the 

 boat above. To this end I propose to use the well-known acoustic properties 

 of water. Above the deck of the sounder a large bell is attached. A hammer 

 is so placed that the raised ribs on the drill-tube lift the hammer and again 

 allow it to fall forcibly on the bell four times in a revolution of the drill, a 

 strong spring occasioning the blow. A telephone suspended beneath the 

 surface of the water above enables these strokes of the hammer to be heard. 

 There is no reason to anticipate any difficulty in this. Submarine bells are 

 heard under much more disturbed conditions of the water and at a far greater 

 distance than would obtain even at the greatest depths of the ocean. With 

 tliis arrangement it is easy to arrange such distinctive characters for the 

 succession of hammer-strokes as will enable the position of the drill to be 

 known by the listener above, for if the raised pieces are notched at intervals 

 so that one or more strokes are missed in a revolution, or none occurs for an 

 Interval, the vertical position of the drill will be recognized by the character 

 of tlie sounds. It is not difficult even to reckon up the strokes so that the 

 exhaustion of the bottles can be anticipated and the operation of withdrawing 

 the drill proceeded with while there is still power in the engine, so that the 

 drill is reciprocated back and forth while it is being withdrawn, and its 

 release from the ooze in this way facilitated. 



A point of some interest may be mentioned here. There is considerable 

 difficulty in providing a float which will act at the great depths of the ocean. 

 It is possible that a vessel made of hard steel or of aluminium might be 

 designed to resist the pressure and retain some buoyancy. It is very doubtful, 

 however, if at the greatest depths any appreciable buoyancy would remain 

 after strength was secured. At any rate, such a float would be expensive to 

 construct. The use of a light liquid appears to be the only feasible method 

 of surmounting the difficulty. Petrol at a specific gravity 0"7 would make 

 an efficient substance. A volume of 14 litres (J cubic foot) would give a 

 lifting force of about 4-5 kilos. (10 lbs.). The liquid would be, of course, 

 enclosed in a thin-walled vessel permitting the pressure of the water to act 



