Sxxy.—On the Silver Ore of Richmond Hill. 551 
time opened out. The following are its principal mineralogical characters :— 
Massive, nearly homogeneous, cleavage irregular; brittle; structure 
confusedly crystalline; colour black generally, but in some parts reddish ; 
has the lustre of molybdenite; hardness about 4:5; specific gravity, 
4:817. 
Ata low heat (a little under that of redness) it fuses readily in parts, 
and with much intumescence. 
The sample analyzed contained 15:4 per cent. of siliceous matter, princi- 
pally quartz, also a little oxy-sulphide of antimony, both of which are 
thrown out in the analytical results stated below. 
ANALYSIS. 
Sulphide of Lead tes T T Vis 36:12 
» Antimony ... os di bos 22:20 
» Bismuth ... tes stk is Traces. 
ĝ Copper... ids ie i.i 19:81 
i Iron id iti T T 18:59 
y Zine T bat ái ai 5:87 
ji Silver ott iis bi. dá 2°39 
ii Manganese iui d Ai "52 
100:00 
The proportion of antimony sulphide to the other sulphides is about as 
2 to 7, and its formula appears to be Sb? S? + 6 (Pb. Cu. Zn. Fe. Ag. $.), 
that of Tetrahedrite is Sb? S? + 4 (Pb. Cu. Fe. Zn. Ag. 8.) 
After comparing it with the Tetrahedrites very carefully I am led to look 
upon it as belonging to this group of minerals, although it diverges from 
any variety of it heretofore announced, and this to such an extent that I 
have no hesitation in making a new variety of it, to which I would give the 
name of Richmondite, after the hill in which it occurs, this being in accord- 
ance with Dr. Hector’s suggestion to me on the subject. It is distinguished 
from other varieties of this very variable mineral by containing a low pro- 
portion of copper, for which lead appears to be substituted. 
Art. LXXXV.—On a useful modification of common Writing Ink, By 
Wit1am Sxey, Analyist to the Geological Survey of New Zealand. 
[Read before the Wellington Philosophical Society, 24th February, 1877.) 
Tur subject of the improvement of our common Writing Ink (/ferro-gallic 
ink) has lately been forced upon me by the proceedings here of a certain 
gentleman, a vendor of pens. These pens were alleged by him to be, at 
