44 Ohservalions on the Study of Mineralogy. 



large cities, aiul oivlv view minerals in cabinets, are led to enter- 

 tain the idea, thaX in the mineral kingdom, nature is in a state of 

 profound repose, and that all the different minerals at present 

 existing, are coeval with the globe itself. It is true, that when 

 minerals aie taken from the mine and placed in cabinets, they 

 appear to undergo no fintber change, and to be imperishable; but 

 in their native repositories, changes are constantly though slowly 

 taking place ; they increase in size, advance to maturity, and 

 afterwards decay more or less rapidly, though the life of a mi- 

 neral, if we may use the expression, extends far beyond tlie du- 

 ration of life in animals oe vegetables. 



It is worthv of particular attention, that certain species of mi- 

 nerals, very dissimilar in their composition, are almost always as- 

 sociated together. Now, to use the words of the late Bishop of 

 Landaff, " Though it may be too much to infer, that one of these 

 substances arises from the natural decomposition of the other, 

 juxtaposition in the bowels of the earth being no certain proof of 

 their being derived from each other ; yet the mind cannot help 

 conjecturing, that a more improved state of mineralogy will show 

 some connexion in their origin." — Chemical Essays, vol. iv. 



When the same species of mineral from different parts of the 

 world always contains a certain substance that appears to the su- 

 perficial observer to be foreign to it ; the common origin of both 

 substances may be inferred with still greater probability. Thus 

 galena (the common ore of lead) almost invariably contains a por- 

 tion of silver. This is the case with the common lead-ore in every 

 part of England, though not a particle of silver-ore has been dis- 

 covered there, except in Cornwall and Devonshire. Such facts 

 particularly deserve the attention of the philosophical mineralo- 

 gist, and I have been careful to notice them, in order to excite 

 a spirit of inquiry. Can we say in the above instance, that the 

 lead was forming into silver, but was arrested in its progress; or 

 is the change now taking place ? 1 do not deem it unphiloso- 

 phical to believe, that the vivifying influence of creative energy 

 descends to the deepest recesses of the earth, acting according 

 to lau's as regular as those which govern the motion of the planets 

 in the heavens. 



'' Meiit affitat niolem, et mafftio se corpore miscet." — Virg. 



' One pervading soul 



Fills the great mass, and mingles with the whole." 



The combined effects of magnetism, electricity, crystalline po- 

 larity, and chemical affinity, are probably united with other causes 

 at present unknown, producing all the various changes in the 

 mineral kingdom, including volcanic phaenomena. But in what- 

 ever manner these changes are effected, they are undoubtedly 



going 



