Dr. Walter Flight — History of Meteorites. 365 



ordinary hydrogen tube, underwent a change ; the light in the broad 

 portion became a straight, hazy stream, of a dull greenish-white 

 colour, similar to that observed in a tube containing either of the 

 oxides of carbon. When the tube containing the metal was raised 

 to low redness, only a small quantity of gas was given off. Wright 

 did not measure the amount of gas removed by the pump, but has 

 calculated this quantity from an observation of the degree to which 

 1 cc. of the gas lowered the guage of the instrument. He finds in 

 this way the mixed gases extracted to have occupied 4*75 times the 

 volume of the metal. While this exceeds the quantity which Graham 

 and Mallet noticed in their investigations, the author believes that 

 the whole amount was by no means exhausted, and ascribes the excess 

 to the fact of the metal which he used having been in a fine state of 

 division. 



1810. — Brahin, Minsk, Russia. 1 



Two large meteoric masses were found at Brahin in the early part 

 of this century ; the dates of their discovery are variously given as 

 1810 and 1820, and they were first described in 1822. They bear 

 the closest analogy to "the Pallas iron " in structure, and with it 

 belong to the small class of siderolites. The Brahin iron was very 

 imperfectly examined by Laugier in 1823, who confined his analysis 

 to that of the iron. Since that time it has not been investigated 

 except in one respect by Bose, who a few years ago noticed that the 

 olivine was traversed by canals, as the Krasnoyarsk olivine is (see 

 page 313, note). Bammelsberg, who has recently examined this 

 siderolite, finds the metallic portion to consist of : 



Iron = 88-96; Nickel and Cobalt = 11-04. Total = 100. 



During the half century which has elapsed since Laugier's time, 

 new and refined methods of analysis have been devised, and Bam- 

 melsberg now finds a per-centage of nickel and cobalt more than four 

 times as great as that given by the original observer. The per-centage 

 is close to that found by Berzelius in the metallic portion of the 

 Krasnojarsk siderolite (11*19 per cent.) ; so that they have a compo- 

 sition closely according with the formula Ni Fe 8 . 



The olivine, now analysed for the first time, has the composition : 



Silicic acid 37-58 



Iron (manganese) protoxide 18*85 



Magnesia 43-32 



99 -.75 

 These numbers, contrary to expectation, do not agree with those 

 resulting from the analysis of the Pallas olivine ; above we have Fe 

 and Mg in the ratio 1:4; in the Pallas olivine about 1 : 8. It is not a 

 little remarkable, however, that the Brahin olivine has the same com- 

 position as that of the Atacama siderolite analysed by Schmid, the 

 iron whereof has been shown by Bunsen to contain Nickel =10*25, 

 and Cobalt = 0*70 (see page 77, note). 



1 C. Kammelsberg. Monatsber. Ah. Wiss. Berlin, 1870, lxx. 440. 



