O10 Scientific Proceedings, Royal Dublin Society. 
described in this Paper. It is of the nature of a drill, electrically 
driven, which will, when lowered to the bottom of the sea, bore 
out a cylindrical portion of an uncovered rock, detach this from 
the parent rock, and retain a hold of the specimen till the appa- 
ratus is raised in safety to the surface. The nature of the rock 
ean then be examined at leisure. In the case of the coral reef, its 
vitality could thus be investigated. 
A. great variety of contrivances, and on various sales of magni- 
‘tude, ean be devised for accomplishing the end in view, having all - 
the essential character of an electrically driven drill. Doubtless 
the form described here admits of improvement. Practice would 
probably suggest many additions. I merely describe a form 
which, while enabling, it is hoped, the desired result to be attained 
in many cases, will be sufficient to test the feasibility of the appara 
‘tus at small expense. 
Plate XX. shows, in part diagrammatically, a vertical section of 
the apparatus to a scale of one-fourth proposed trial dimensions. 
The rapidity, or the power of the drill, will of course depend upon 
what dimensions we confer upon the motor. The mass of the 
whole, as acting to confer immobility upon the apparatus while 
the drill is at work, also enters into consideration. In the trial 
form proposed, it is not intended to secure a high rate of working 
speed, the idea being that improvement in this direction is assured 
upon increased expenditure on the construction of the apparatus. 
The drill D consists of a steel tube set with diamonds. The 
eutting edge is chisel-shaped, to secure a more rapid bite when the 
rock is first attacked, and also to facilitate the escape of detritus. 
The boring edge is about three-sixteenths of an inch wide in 
cross-section to allow for the housing of the cutting blades which 
sever, by a horizontal cut, the connection of the drilled-out plug 
with the rock. It must be remembered, in considering the 
rate of speed and the nature of the action of the drill, that 
there is complete lubrication of the cutting edge throughout, and. 
that a high rate of speed is therefore allowable. Further, a cowl 
may be attached to the upper open end of the drill-tube so con- 
structed as to direct a current of water downwards through the 
“tube upon the rotation of the latter, thus washing all detritus out 
ak he boring. 
