364 Dr. Walter Flight — History of Meteorites. 



The oxygen ratios of acid and bases in the soluble part 18-63 : 19-53 

 show the silicate which gelatinised with acid to be an olivine, re- 

 markable, it should be observed, for the amount of lime it contains. 



Von Baumhauer gives the formula I h ^ I V SiO i as an expression 



of its composition. In the insoluble part the oxygen ratio of acid 

 and bases is 30-28 : 14-15, and here the presence of more than five 

 per cent, of alumina points to the probable occurrence of a felspar 

 in this portion of the stone. If we assume that the iron oxide, magnesia, 

 and lime, 1 are present as a bronzite, the oxygen ratios of the alumina, 

 alkalies, and residual silica, differ very little from 3:1:9, or those 

 of oligoclase, soda-lime felspar, in some varieties of which a con- 

 siderable proportion of the soda is found replaced by potash. 



1808.— Red River, Texas. 2 



As Graham 3 has shown that the Lenarto meteoric iron contains 

 2-85 times its volume of occluded hydrogen, carbonic oxide, and 

 nitrogen, and Mallet (see page 28) has found 3-17 times its volume of 

 hydrogen, carbonic oxide, carbonic acid, and nitrogen occluded in the 

 meteoric iron of Augusta Co., Virginia, it occurred to the author that 

 it might be possible to detect in the gas of these irons the unknown 

 gaseous elements assumed to be present in the solar corona and 

 chromosphere. The investigation was undertaken with the hope 

 that the spectroscope would reveal them, if present, although their 

 small amount or peculiar characters might render their detection by 

 ordinary chemical methods difficult or impossible. 



A vacuum tube of the form ordinarily employed in spectroscopic 

 work was attached to a branch of the exhaust tube of a Sprengel 

 pump, and a preliminary examination was made of the lines exhibited 

 by this tube after simple withdrawal of the air. As Plucker and 

 Hittorf 4 have already shown, lines of hydrogen and bands due to 

 carbon make their appearance as soon as the limit of exhaustion has 

 been attained ; the author noticed the red hydrogen line when the 

 tension fell to 4 or 5 mm., and other hydrogen lines when a higher 

 degree of rarefaction was attained. Mercury lines, varying in bright- 

 ness with the temperature of the room, are also to be seen. His in- 

 vestigations were directed to an examination of the gases of the great 

 Texas meteorite, preserved in the Mineral Collection of Yale Col- 

 lege, and the meteoric irons of Tazewell Co. and Arva, Hungary 

 (which see). The iron was in very small particles — chips produced 

 by the borer, and the exhaustion was proceeded with without the 

 application of heat. He noticed that the iron gave off a portion of 

 its gas at ordinary temperatures ; and when the tension was reduced to 

 4 mm., Ha and H# were bright and distinct, and Hy visible, while 

 the carbon bands were also distinctly seen. When a gentle heat was 

 applied, the tube, which had hitherto presented the appearance of an 



1 The bronzite of Harzbiurg, analysed by Streng, contains lime. 



2 A. W. Wright. Amer. Jour. Sc. 1875, ix. 294. 



3 T. Graham. Troc. Royal Soc, xv. 502. 



4 J. Plucker and W. Hittorf. Phil. Transactions, civ. 1. 



