50 E. F. PITTMAN. 
Antimony ... ao ee 3642 
Arsenic hee ae a i traes 
Lead... ate mes aoe 2-79 
Copper is eo ads 52 
Tron ... oe ea ae 5-18 
Calcium Se But sae 4°84 
Magnesium .. , “Xs 
Insoluble matter (g Se i 5-20 
Chlorine ke Fre 14 
peer 6-0] ( mean of va 
eee eee eee experiments | q 
Oxygen ae ae ee yt by direct | 
weighing. — 
99-37 
At the suggestion of Professor Liversidge a polished surface of | | 
the substance was then etched by allowing a solution of strong | 
ammonia to stand on it for some hours. ‘The result clearly shows | 
that the chloride of silver has been removed leaving the am 
moniate of silver in relief. 
II.—The second substance is clearly an alteration product 
derived from argentiferous galena. It is dark grey in colour— 
has a cubical structure, being in fact pseudomorphous after gale 
It is sectile—has a variable specific gravity—that of the specimen 
on the table being 6°38. Its chemical composition is chiefly 
sulphate of lead and sulphide of silver in widely varying propor 
tions, with small quantities of sulphide of iron, sulphide of cop 
and sulphide of lead. 
Altogether four analyses of this interesting substance have P* 
made in ihe Geological Survey Laboratory, Nos. I., IL. and! 
being by Mr. J. C. H. Mingaye, and No. IV., by Mr. Harold 
White. 
I. IL. II. IV. 
Moisture ws 08 'S8b,8, -44 Moisture -14 FeO. 
Ag.S Sulphide of Silver77-99 7662 13-25 1068: 
Cu u,S_ ” Copper 62 32. 1°82 
