SCIENTIFIC SUMMARY. 
327 
acid. Atopite is found at Laangban disseminated through, hedyphane which 
occurs in fine veins and layers in rhodonite. It crystallizes in regular 
octahedra, and has a hardness of 5*5-6*0, and the specific gravity of 5*03. — 
Ekdemite is a coarsely crystalline mineral of a bright yellow colour with a 
faint greenish tinge ; in thin plates it is translucent and is uniaxial and 
exhibits a distinct basal cleavage. The hardness is 2*5-3*0 and the specific 
gravity = 7T4. The solution of this mineral in acid reduces potassium per- 
manganate. A pure specimen of ekdemite was found to possess the follow- 
ing composition : 
Lead oxide 58*25 
Lead 23*39 
Chlorine 8*00 
Arsenious acid 10*60 
100*24 
These numbers indicate the formula 5Pb0,As 2 0 3 + 2PbCl 2 as that of 
the new species. The mineral occurs, imperfectly foliated, in manganocalcite 
and as greenish yellow deposits incrusting it. The author also found at 
Laangban small lemon-yellow granules enclosed in the calcite which fills the 
cavities of a resin-brown coloured garnet j these granules contain arsenic, lead, 
and chlorine, but a satisfactory analysis of them could not be performed 
from want of material. He states that they crystallize in the rhombic 
system, and regarding them as ekdemite, he believes the new mineral to be 
dimorphous. — Hydrocerussite is a white mineral enclosing native lead 5 it 
appears to be a hydrated lead carbonate having the composition represented 
by the formula 2Pb0,C0 2 + H 2 0. Hyalotekite is a white or pearl-grey, 
semi-translucent mineral, possessing a coarsely crystalline structure, and 
cleaving in two directions lying 90° or nearly 90° apart. It is easily fusible 
and is insoluble in hydrochloric acid and sulphuric acid. An imperfect 
analysis showed it to contain the following ingredients : 
Silicic acid . 
Lead oxide . 
Baryta . 
Lime . 
Loss on ignition . 
Alumina, potash, &c. 
39*62 per cent. 
25*30 „ 
20*66 „ 
7*00 „ 
0*82 „ 
not determined. 
In appearance it very closely resembles a greyish- white felspar, and it 
occurs in association with hedyphane and schefferite. — Ganomalite is the 
name which was given by the author in 1876 to a lead silicate occurring at 
Laangban. As it has recently transpired that certain specimens which were 
believed to be ganomalite contain no lead whatever, and are in reality 
tephroite (manganese silicate), Nordenskjold has published fuller details and 
an apalysis of the mineral. Ganomalite occurs massive, associated with 
tephroite, which it so closely resembles that any specimen under examination 
should be tested with the blowpipe. It is white or greyish-white, possesses 
marked doubly refractive power, has a hardness of 4*0, and the specific 
gravity of 4*98. When heated with soda in the reducing flame, the yellow 
crust on the charcoal and the reduced metal indicate the presence of lead. 
The composition of a specimen of this mineral was found to be : — 
