420 Chronicles of Science. [July? 



series of researches on the absorption of gases by metals ; and, 

 quite recently, these investigations have, in a most unexpected man- 

 ner, yielded results which promise to throw considerable light on 

 the origin of meteorites. His experiments have shown that many 

 metals, when heated in certain gaseous media, are capable of ab- 

 sorbing a large volume of the gas which may be retained at ordinary 

 temperatures, for an indefinite period, condensed within the inter- 

 stices of the metal, but ready to be evolved at any moment by a 

 sufficient elevation of temperature ; this power being denoted by the 

 term " occlusion." Pure iron, for example, heated to low redness 

 in carbonic oxide, occludes upwards of four times its volume of the gas ; 

 and hence a piece of ordinary wrought iron heated in vacuo yields 

 a considerable amount of carbonic oxide derived from the atmosphere 

 of the furnace in which it was prepared. It became, therefore, a 

 matter of much interest to determine whether meteoric iron contained 

 any, and if any, what kind of occluded gas ; and experiments were 

 accordingly made with the Lenarto meteorite. When a carefully 

 cleaned piece of this iron is heated in a tube connected with the ex- 

 hausting apparatus known as "Sprengel's pump," it yields 2*85 

 times its volume of gas, having the following composition : — 



Hydrogen 85-68 



Carbonic oxide 4-46 



Nitrogen 9*86 



100-00 



Now since the occluded gas is in every case a remnant of the atmo- 

 sphere in which the metal was last ignited, the conclusion seems 

 almost inevitable that the meteorite in question must have been 

 intensely heated, before reaching our earth, in a dense atmosphere 

 highly charged with hydrogen, — a conclusion which receives ad- 

 ditional interest when studied in connection with Messrs. Huggins 

 and Miller's researches on the stellar spectra, and with the Father 

 Secchi's recent attempt to classify the fixed stars according to their 

 spectra, hydrogen being the characteristic element in those of which 

 a Lyrse is the type. The discovery has been communicated to the 

 Royal Society by the Master of the Mint, and has been brought 

 before the audience of the Eoyal Institution by Dr. Odling. 



M. Dumas has called the attention of the Academy of Sciences 

 of France to a peculiar substance, the origin of which is un- 

 known, which possesses the general character of anthracite, but ap- 

 proaches the diamond in hardness. Attention has been especially 

 directed to this, hoping that the source from which it has been 

 derived may be discovered, and the peculiarities further examined. 



Dr. Schrauf, of the Imperial Museum of Vienna, has communi- 

 cated to the Academy * the correction of the weight of the great 

 * Sitzungsb. d. k. Ac. d. Wiss., Bd. LIV., p. 5. 



