INTERNAL STRUCTURE OF SOME GOLD CRYSTALS. 143 



a matter of some moment; if it is too great, the drops of 

 mercury roll down too rapidly and break when they hit the 

 side of the glass at M; if too small the drops coalesce, 

 becoming unnecessarily large and the rate of exhaustion is 

 slow. The shape of the corner of the tube at L should be 

 such as to offer no obstruction to the motion of the drops 

 but to allow them to roll over on to the mouth of the fall 

 tube without hitting the side of the glass at M. If the 

 motion is checked the drops collect together, become 

 uselessly big and the intervals between drops in the fall 

 tube are too long. 



The glass blowing for the various pumps which have 

 been constructed in connection with the experiments to fix 

 the details of the design has been carried out by Mr. Carl 

 Sharpe, assistant in the laboratory. The glass working 

 presents no difficulties if the pieces are assembled with the 

 aid of a hand oxyhydrogen burner. 



On the INTERNAL STRUCTURE of some GOLD 

 CRYSTALS. 



By A. LlVERSIDGE, LL.D., F.R.S. 



Professor of Chemistry in the University of Sydney. 



[With Plates X. - XII.] 



[Read before the Royal Society of N. S. Wales, October 2, 1907.] 



The specimens figured and described in this note consisted 

 of some groups of crystals, and two simple fairly well 

 developed rhombic dodecohedra, from places in New South 

 Wales, South Australia and Queensland. 



