330 Cc. W. MARSH. 
completely so if first fused with potassium bi-sulphate. After 
the removal of silica in the usual manner, alumina is thrown down 
by ammonia, from the filtrate lime is precipitated by ammonium 
oxalate, and a little magnesia, by sodium phosphate. Black 
variety gives manganese reaction with borax lead, otherwise 
essentially similar to above. 
[The very small specimen of the white coralloid mineral for- 
warded to me consists of chalcedony coated with what appears to 
be Gibbsite or aluminium hydrate; the coating has a greasy feel, 
and under the microscope is seen to have a fibrous structure, and 
on scraping it off a white fibrous matted powder is obtained; this 
gives the reactions described by Mr. Marsh, except that I did not 
obtain any sublimate, and I am inclined to think that the silica. 
left in the microcosmic salt bead is not combined with the alumina 
but intermingled mechanically. The black coralloid portions 
consist mainly of black oxide of manganese, and when treated 
- with HCl give off chlorine copiously and leave a siliceous skeleton 
or core in much the same way as the stalactitic hematite from 
the Mount Morgan Gold Mine.—(Journ. Royal Soc. N.S. Wales, 
1891, p. 236)—A. Liversidge. | 
(No. 3) Is a mineral of which we have numerous specimens. 
It usually occurs as implanted connected crystals on limonite. It 
consists principally of lead, with varying proportions of phosphorus 
arsenic and chlorine ; some with, others without lime, on some 
specimens the crystals are coated with a bright gold-yellow to 
copper-red film, which I have not yet been able to satisfactorily 
determine. From some of these films I have got the reaction for 
molybdic acid, whilst from others, apparently similar, no such 
reactions could be obtained. 
These minerals appear to form various links between mimetite 
and pyromorphite, or more properly speaking a combination in 
various proportions of the two minerals. But as they cannot be 
classed directly as either, and as they sometimes contain lime, I 
have classed them irrespective of their slight changes in compo- 
sition as hedyphane. Moreover there are many points of essential 
