POPULAR SCIENCE REVIEW. 
550 
fibrous structure is seen, which in some cases is so distinct that the 
mineral has probably been considered to be a compact variety of Thom - 
sonite. It has a highly silky lustre, weathering dull • it cleaves readily in 
the direction of its fibres, and is translucent on the edges. Its hardness 
is represented by 5 ; it is rather brittle, and has a specific gravity of 2*08. 
It has the following chemical composition 
Soda 
2*35 
Lime 
3*46 
Alumina ... 
12-77 
Silica 
• . a 
« . • 
68-40 
Water ... 
„ ® j 
13-02 
100-00 
On comparing it with minerals containing the same elements, it is found 
to be nearest to heulandite in chemical composition ; and Professor How 
considers it to be the most highly silicated of the aluminous non-magnesian 
hydrous silicates yet described.— -Vide Mining and Smelting Magazine , 
No. 28. 
A new Steatitic Mineral. — A peculiar mineral of a green colour, and 
having a sort of prismatic structure, was found some time since in the 
lead-mining district of the County Dublin. Mr. Ormsby, to whom is due 
the merit of the discovery, gives the following description of it : — Its 
specific gravity is 2*738 ; it scratches gypsum slightly, and is deeply cut 
by calcite, so that its hardness is a little above 2°. It is unctuous to the 
touch, although the analysis gives but a very slight percentage of mag- 
nesia. When held in the forceps before the blowpipe, it glows brightly, 
becomes white, and slightly fuses on the edge ; it dissolves in borax, and 
leaves a siliceous skeleton ; the bead is colourless when cold but greenish 
when hot, showing the presence of iron ; no manganese could be detected 
even with the nitre test. The substances entering into its composition are 
silica, alumina, iron, potass, soda, lime, magnesia, lithia, and water. — . 
Vide Dublin Quarterly Journal of Science, April, 1864. 
Presence of Thallium in Lepidolite. — It has been announced by Professor 
Schrotter, in a communication to the Vienna Academy of Sciences, that 
thallium has been found by him in both lepidolite and mica. It is not 
necessary to use a large quantity of the material in order to detect the 
presence of this metal. His method of procedure is this : — Taking the 
mixture of the double chlorides of platinum with the potassium caesium, 
rubidium, and thallium, obtained from the above sources, he removes the 
potassium, and then reduces the other chlorides in a stream of hydrogen 
at a low temperature. Next he treats the well-washed, spongy mass of 
platinum with sulphuric acid, and by the repeated washing-out of this, 
obtains a solution which shows the characteristic reactions of thallium. 
Mr. Crookes, however, is inclined to doubt the accuracy of Professor 
Sclnotter’s process, and appears inclined to attribute the results obtained 
by the latter chemist to the circumstance that in sulphuric acid—- the 
liquid employed — thallium is frequently found. — Vide Journal fur 
PraJct Chem., I., 1864, and Chemical News , No. 227. 
