446 



REPORT — 1895. 



Fig. G. 



Tuiular loring rods'^ 



Q 



Gwu/uL 



woffht/ 



Steel H'ln. 



this box was to be a solution of gum mastic, from which the gum could 

 be thrown down by the admixture of water that would be allowed to gain 



access by the opening of a stop- 

 per manipulated from above. 

 The whole could afterwards be 

 lifted without altering the re- 

 lative positions of the parts. 

 Anothei- proposal was, first, to 

 grind the top of the core to a 

 level surface (fig. 4), and then 

 to let down a strong needle sup- 

 ported on a spring centre, and 

 having steel points affixed under- 

 neath, two near its north end 

 and one near its south end. By 

 releasing a weight, or putting 

 on the steady downward pres- 

 sure of a screw, the points wei-e 

 to be forced into the rock, giving 

 the line of meridian in the most 

 direct manner. A plan was also 

 suggested for lowering a mass of 

 plastic material (fig. 5), such as 

 wax, on to the roughly fractured 

 top of the fixed core, and after 

 an impression had been taken, 

 the frame carrying the wax 

 was, before withdrawal, to be 

 marked by a magnetic needle 

 suspended above its upper sur- 

 face. This was to be accom- 

 plished by having an annular 

 groove, also filled in with wax, 

 on the upper side of the carrier. 

 The needle would be balanced 

 on a spring point at the centre 

 of this circle, and would have 

 differently shaped points on its 

 under side at either end just 

 over the ring of wax. By 2:)ress- 

 ing these down when they had 

 finally come to rest, the direc- 

 tion would be given upon the 

 carrier, ready for transference, 

 first to the cast of the core, and 

 afterwards to the core itself, 





Core^ UU?e 



/tar/ur 

 Core, 



Scale, 1 in. to 8 ft. 



when this was brought to the 



surface. 



But there were difficulties in 



arranging an instrument that 

 would be likely to work satisfactorily on these lines. The risk of disturb- 

 ing the needle duiing the descent of a weight or the inflow of a liquid was 

 very great ; but the principal objection was, that the tubes to which the 



