Royal Society. 311 



quantities of aqueous vapour in the atmosphere in all probability 

 produces a considerable differerence of rate in the decomposition 

 effected by the leaf, and may in fact end in carbonic acid and 

 water being attacked in another ratio than that given as the fun- 

 damental equation of decomposition. Thus the same plant in 

 different atmospheric conditions may elaborate different sub- 

 stances. 



XXXVII. Proceedings of Learned Societies. 



ROYAL SOCIETY, 



[Continued from p. 232.] 



May 30, 18/2.— George Biddell Airy, C.B., President, in the Chair. 



T^HE following communication was read : — 

 •*- "Examination of the Gases occluded in Meteoric Iron from 

 Augusta Co., Virginia." By J. W. Mallet, Ph.D., M.D., Professor 

 of Analytical and Applied Chemistry, University of Virginia. 



The investigation by Graham of the gases given off by meteoric 

 iron from Lenarto, in Hungary, when heated in a vacuum pro- 

 duced by a Sprengel pump, excited much interest at the time of 

 publication*, but does not seem to have been followed up by any 

 similar examination of other meteorites. I have made use of pieces 

 of the iron found about three years ago in Augusta Co., Virginia, 

 the description and analysis of which were published by me in the 

 'American Journal of Science' for July 18/1, in order to repeat 

 the experiment of Graham, and ascertain whether similar results 

 to his would be obtained. A large part of the work of the extrac- 

 tion and analysis of the gaseous contents of this iron has been done 

 by two of the students in my laboratory, Mr. F. P. Dunnington of 

 Baltimore, and Mr. J. B. Adger, of South Carolina, to whom I am 

 much indebted for their assistance. 



Two preliminary experiments were made, — the first with some 

 shavings from the cutting of the iron upon a planing-machine ; the 

 second with a solid piece of the metal planed to smooth, clean sur- 

 faces, and quite free from any crust or scale. The shavings were 

 subjected to the purification practised by Graham, namely, washing 

 with a hot solution of potassic hydrate, followed by washing with 

 distilled water and thorough drying. The solid strip of iron was 

 not so treated, care having been taken to use no oil upon the tool 

 employed in cutting it. Both specimens gave off gas readily when 

 heated in the Sprengel vacuum, the amount in each case being- 

 larger in proportion to the bulk of the iron than in the experiment of 

 Graham ; and analysis showed that the same gases were present as 

 those found by him, with the addition of carbonic anhydride in not 

 inconsiderable amount. 



* Proc. Eoy. Soc. xv. p. 502. Phil. Mag. S. 4. vol. xxxiv. p. 239, 



