SCIENTIFIC SUMMARY. 
173 
crystals which in form, hardness, specific gravity, colour, streak, and 
chemical composition, agreed with pyrolusite. This experiment hears on the 
question, how has pyrolusite been produced in nature P and the author made 
numberless experiments with the purpose of solving this problem. He has, 
however, not succeeded by any other method than that given above in 
forming pyrolusite. While the author ventures to believe the method 
which has been hit upon as that employed by nature for the formation of 
pyrolusite, he directs attention rightly to the almost absolute purity of the 
natural product, and shows also that by the artificial method, even when 
impurities are added to the manganese nitrate, crystals of pyrolusite, which 
separate, are likewise pure. He concludes from this that in nature or by the 
artificial formation of pyrolusite the iron nitrate which is added as an im- 
purity separates before the crystallization of the pyrolusite. 
The Crystalline forms of Ferromanganese. — This interesting question has 
been investigated by E. Mallard. Alloys of these metals have been formed 
containing manganese varying in amount from 11 to 85 per cent. With 
quantities of manganese varying from 11 to 52 or 53 per cent, the crystalline 
form remains unchanged : a rhombic prism oo P (110) of 112° 33' with the 
pinacoid oo P oo (010). The pinacoid is so largely developed generally that 
the prism’s faces are usually in the form of lateral stripes. When the manga- 
nese reaches 52 to 55 per cent the crystalline form suddenly becomes another, 
which in its general habit approaches small hexagonal prisms, and consists of 
a rhombic combination oo P (110) with an angle of about 120° and the pina- 
coid oo P 55 (010). {Jalirhuch fur Miner alogie, 1879, 617.) 
Vesbium and Norwegium. — In a few notes on these bodies by C. itammels- 
berg, which appear in the Berichte der deutschen chem. Gesellschaft , he 
points out that Signor A. Scacchi has made a communication to the Academy 
of Sciences of Naples on an examination of certain green and yellow incrusta- 
tions which cover the fissures in the lava of Vesuvius of the year 1631. 
They consist of silicates, and contain copper, lead, and a body which he con- 
siders new, and which he has designated Vesbium, from the old name of 
Vesuvius. The small quantities of this substance have allowed of only pre- 
liminary investigations. It appears to form a metallic acid of a red colour, 
giving colourless alkaline salts, which turn yellow on the addition of an 
acid. The silver salt is red or orange, the copper salt yellowish-green. 
Sulphuretted hydrogen gives a brown precipitate and a blue liquid, which is 
rendered brown by zinc. Before the blowpipe it communicates to microcosmic 
salt a yellow colour in the outer flame and a green one in the inner. Scacchi 
does not believe in the presence of molybdenum or vanadium, though many 
considerations render the latter not improbable. The memoir contains no 
numerical data beyond the statement that the silver salt contains 48‘8 per 
cent of silver (Ag V0 3 =52T Ag). More definite are the statements made by 
Dr. Tallef Dalell [See Popular Science JRevietu, 1879, 423], on the sup- 
posed new metal from the red nickel pyrites of Kragcroe which he has called 
Norwegium (Ng.). He finds it white, not very ductile, with a specific 
gravity of 9*44 ; it melts at 350° and dissolves in nitric acid with a blue 
colour, which becomes green on dilution. On the reduction of the brownish 
oxide in hydrogen the proportion of oxygen was found to be 9’6 to 10T5. 
On the supposition that the oxide has the formula, NgO, we have Ng=150‘6 
