Botany. 455 
bearing berzellite, associated with barite, tephroite, calcite, and 
hausmannite, in veins and nests in the vicinity of Sjogrufan, 
Grythyttan parish, Orebro, Sweden. ‘The new mineral, to which 
the name pyrrhoarsenite has been given, has a color resembling 
that of crocoite. It has a hardness of 4, and is soluble in hydro- 
chloric acid. It possesses the optical properties of berzellite, and a 
composition as follows :— 
As,0,+S8b,0; MnO CaO MgO SiO, H,O Al,0,+Fe,0, 
58.06 17.96 18.68 3.58 1.02  .85 traces. 
which may be represented by the formula (Ca,Mn.,Mg),(As, 
Sb ),0,. 
MIscELLANEOUS.—Cohen! has re-investigated the subject of the 
pleochroic halos (Höfe) in the biotites of granite and gneiss, and is 
thereby led to the conclusion that they are produced by the accumu- 
lation of organic substances in the neighborhood of the inclusions 
they surround, and are not due to the aggregation of mica mole- 
cules richer in iron than those forming the, main portion of the 
mineral in which the halos occur. He finds, contrary to the 
experience of Lévy,’ that the halos are not affected by treatment 
with hydrochloric acid, as they should be if they contain a large 
proportion of iron, but that they are destroyed by heating toa 
temperature considerably higher than that which is necessary to 
obliterate the halos in muscovite and cordierite, in which minerals 
. this phenomena is now generally believed to be due in some way to 
an organic substance. Franklinite, together with its natural asso- 
ciate, zincite, has been artificially produced by Gorgeu® by subject- 
ng to a cherry-red heat an intimate mixture of one part of sodium 
sulphate, one-half part of zinc sulphate, a quarter to a half part of 
ferric sulphate, and a little manganese sulphate.‘ 
BOTANY." 
are neglected by botanists in general, who seem to have an aversion 
to all aquatic plants, mainly, it is presumed, from the fact that the 
collection of aquatics is a specialty. One must go prepared with 
