SCIENTIFIC SUMMARY. 
109 
before the blow-pipe, forming a black non-magnetic mass. The chief 
constituents of vietinghofite are: niobic acid, 51-00 per cent.; iron 
protoxide, 23-00 per cent. ; uranium oxide, 8-85 per cent. ; yttria, 6-57 per 
cent. ; and manganese protoxide, 2-67 per cent. The new mineral appears 
therefore, to be a variety of Samarskite. — Bull, de V Acad. St. Petersbourg , 
xxiii. p. 463. 
Touchstone . — Dumas has recently published the results of an analysis of 
a specimen of touchstone, probably the very specimen examined by 
Vauquelin. (“ Journ. Ohim. Pharm.,” xxii. p. 426). The silica present 
amounts to 81*40 per cent. He believes the touchstone to be a variety of 
fossil wood, a small portion of the woody tissue of which has not been 
replaced by silica. Certain specimens from the Alps yield on ignition an 
ash which consists of silica only ; they still retain, however, sufficient 
•evidence of structure to allow of the determination of the genus whence they 
are derived. A microscopic examination of sections of touchstone by 
Begnault has shown that in some cases the organic matter present consists 
of a variety of bitumen resulting from the decomposition of the tissues of 
the original wood ; the intense black colour of that substance, as it fills the 
cell-walls and spaces once occupied by fibrous structure, renders the form 
and details of the cellular portion apparent. 
Meteorites . — Professor Tschermak, of Vienna, has issued a short notice of 
the important additions made, down to the end of September, 1877, to the col- 
lection of meteorites under his care. During the last five years stones from 
twelve, and irons from eight, new localities have been added. The remain- 
ing (fourth) fragment of the giant stone of Knyahinya has been acquired by 
purchase, and it now weighs, in its entirety, 293 kilog. A large mass of, 
iron, weighing 198 kilog., from the Boison de Mapini, Cohahuila, Mexico, 
has likewise been acquired. The total number of falls now represented is 
308 ; in 1819 the number was 36 ; in 1843 it rose to 94 ; in 1859 it was 
176, and in 1868 it attained 244. Since 1869 Professor Tschermak has 
added specimens of 64 falls, previously not represented, to the collection ; 
and the total weight of meteoric matter has during the interval been 
increased from 570 kilog. to 1025 kilog. The most recent aerolitic showers, 
of which specimens have been secured, are those which occurred at Iowa 
City (Amana), Iowa, February 12, 1875 ; and Zsadany, Temeser Comitat, 
Hungary, March 31, 1875; and the last new meteoric iron comes from 
Henntmannsdorf, Pirna, Saxony, and bears the date 1872. 
PHYSICS. 
Magnetism of Nickel. — M. H. Wild has investigated the magnetic pro- 
perties of pure nickel, and comes to the following conclusions. Unlike pure 
-(soft) iron, pure nickel acquires a considerable amount of permanent mag- 
netism, but its maximum is only from one-third to one-half of the permanent 
magnetism acquired by hard steel, according to the goodness of the latter. 
The magnetism remaining in nickel after the cessation of the magnetizing 
influence is less permanent than in well-hardened steel; and the gradual 
loss of magnetism by lapse of time, as also by warming and cooling, is 
