910 The American Naturalist. [October, 
their composition to be simpler than has been supposed. The figures 
obtained by him are : Fe203=56.42%, Ti02=44.26%, corresponding 
to Fe/TiOJ.,. The author thinks that brookite may be Ti,(TiO,)3. 
At the temperature of melting copper the mineral cyaniie, according to 
Vernadsky/3 loses its color, and its characteristic physical and optical 
properties, and assumes those of sillimanite. Hence it is regarded as a 
triclinic form of Al^SiO., whose orthorhombic variety is the last- 
named mineral. The rocks in which cyanite is found (the crystalline 
schists) can therefore not have been formed at high temperatures where 
this mineral is an essential, original component. Hamberg '* has dis- 
covered well -developed crystals of lead in the iron and manganese 
mines of Harstig, at Pajsberg, Sweden. The silver-white crystals are 
imbedded with arsenates in calcite nests. They show the forms O, 
ooOoo , ooO, 2O2, 5O, and oo04, and have a specific gravity of 11.37- 
The author explains the origin of the lead by supposing the reduction 
of lead compounds by arsenious acid in its oxidation to the arsenic form. 
Igelstrom ^'^ records the same mineral as occurring in thin plates and 
fine veins in an amorphous blood-red neotokite-like mineral, abundant 
at the manganese and iron mine Sjogrufvan, in the Parish Grytthyttan, 
Orebro, Sweden. An analysis of a manganese ore from the Crimona 
mine, Augusta Co., Va., yielded Mr. Jarman -.^^ 
MnO O FeA CaO NiO CoO K.,0 Na,0 H,0 Lers. 
78.27 17.61 .62 .09 .22 .27 .18 .23 2.08 .29 
a result which indicate; 
itions the discovery 
• — — and I ^— ^ on pyrite, and \0 
pleonast from Monzoni, and describes a pseudomorph of quartz 
after apophyllite from the Fassathal. Pseudomorphs of hematite, 
after pyrite, found in the calcareous red slate of Torquay, England, 
are described by Solly.^s Mr. Yeates ^ describes a copper pseudo- 
mroph, after azurite, from Grant Co., New Mexico, as consisting 
of spongy copper, into which kaolin has been pressed. A pseudo- 
