BULLETIN 94, UNITED STATES NATIONAL MUSEUM. 

 Analyses of meteoric feldspars. 



• Borgstrom, Bull Comm. geol. Finlande, No. 14, 1903. 

 «Lindstr6m, Ofv. Kongl. Vet.-Akad. Forhandl., 1869, p. 723. 

 •Tschermak, Sitz. Akad. Wiss. Wien, vol. 65, 1872, p. 130. 



From these analyses it would appear that 1 and 2 are to be classed 

 as oligoclase and 3 as labradorite. 



Gaseous constituents. — The fact that hydrogen was given off when 

 the Lenarto (Italy) meteoric iron was heated in a vacuum was first 

 noted by Thomas Graham in 1867. J. W. Mallet, in 1873, found the 

 meteoric iron of Augusta County, Va., under similar circumstances 

 yielded not merely hydrogen but also nitrogen and carbon monoxide 

 (CO) and carbonic acid (CO^). A. A. Wright, in 1875 and 1876, 

 showed (1) that the stony meteorites differ from the iron in having 

 oxides of carbon, chiefly as CO., as their characteristic gases, instead 

 of hydrogen; (2) the proportion of COo given off at low is greater 

 than at high temperatures; (3) the amount of gases contained in a 

 large meteorite, or cluster serving as a cometary nucleus, is sufficient 

 to form the train; (4) the spectrum of the gases is closely identical 

 with that of several comets. 



Doubts which may have been thrown on these results as first an- 

 nounced were eliminated by the later investigations. In the stony 

 (chondritic) meteorites the percentage of CO is conspicuously small 

 compared with that of CO2, while in the irons the conditions are 

 reversed. Recent work by R. T. Chamberlin furnished data for 

 the following summary of averages : 



Subsequently Prof. William Ramsay, of London, detected the prob- 

 able presence of argon and helium. 



Lawrencite. — Protochloride of iron. The exudation of drops of 

 ferrous chloride from freshly cut or broken surfaces of meteoric iron 



