ORIGIN OF ELEMENTARY SUBSTANCES. 141 



confirms the positions assigned for Si, Fe, and An, in the 

 table as forms of Hyn. 



The remarkable resemblance which the members of the 

 iron group have to one another, while their atomic weights 

 are nearly, if not exactly the same, has long been a subject 

 of much interest to philosophical chemists, and if the 

 views which I have enounced respecting the formation of 

 elementary species by condensation be correct, the cause 

 of these resemblances admits of a possible explanation. 

 From the great abundance and wide distribution of iron 

 in nature, it is probable that the vapour of this element 

 would form a zone of considerable depth ; the upper and 

 lower regions of which, by differences of pressure and 

 temperature, might produce allotropic varieties before a 

 definite change to the next higher members in the series 

 occurred. When once varieties of an element were 

 formed, these varieties would be propagated through 

 successive condensations into the next higher members of 

 the series, just as they are found in the palladium and 

 platinum groups of metals. Chemists have already obser- 

 ved that each of the metals of the palladium group 

 appears to be more especially correlated with some 

 particular member of the platinum group, and all are 

 found associated together naturally in the metallic state. 

 If the four members of the platinum group be considered 

 the analogues of the corresponding members of the iron 

 and palladium groups, it will be seen that one of the 

 members of the latter group is missing. M. Sergius 

 Kern, a Kussian chemist, has recently discovered a new 

 metal which he classifies with the platinum group, and 

 has given to it the name of davyum"^". The specific 

 gravity of the new metal was found to be 9*39, and pre- 



* Comptes Eencliis, tcme Ixxxv. pp. 72, 623, 667 (1877). 



