VEIN. 



From the third letter of that work we make the following 

 extraft. 



" In explaining the phenomena which are obfervable in 

 the interior of mountains (it muil however be remembered, 

 tliat I do not include fuch as are evidently of volcanic origin), 

 I do not avail myfelf of thofe great caufes which, by their 

 magnitude, the fuddennefs of their atlion, and by their efFefts, 

 produce fudden changes which take place under our eyes, 

 fuch as fubterranean fires, earthquakes, and the like. I 

 refer thefe phenomena to natural caufes, which, though lefs 

 evident and flower in their operation, are no lefs certain of 

 producing a radical transformation. Of this kind are putre- 

 faction and fermentation. It is of little confequence by 

 what name we dillingui(h this pecuhar aftion exerted by 

 Nature in the mineral kingdom ; it confifts in an inteftine 

 motion in the central parts of the globe, and appears to be 

 produced by water combined with heat in different degrees 

 of intenfity. I obferve fuch changes ftill going on, and can 

 conceive them to continue fo long as the fame furies of opera- 

 tions exift in nature. I am perfuaded that there is conftantly 

 going on in our mountains a variety of transformations, com- 

 pofitions and decompofitions, which not only take place at 

 prefent, but will continue to the end of time. 



" Fermentation, if I may be allowed to call by that name 

 this quality which ails by infenfible degrees, produces 

 the moll perfeft transformations in the bowels of the earth ; 

 fermentation I fay may, according to my theory, alter the en- 

 tire mafs of a mountain ; it may convert granite into gneifs, 

 as this laft only differs from the former in its ilrufture, which 

 is flaty or fchiftofe ; gneifs indeed has no other diftinftive 

 chara-dler than its ftrufture, namely, the regularity and paral- 

 lelifm of its beds, and in fome places a decompofed felfpar 

 approaching to clay. This fermentation may alfo convert 

 greywacke into an argillaceous fchifl, which laft may again 

 by induration become jafper, when this procefs is either di- 

 miniihed or Itopt. By it, alfo, quartz may be converted into 

 clay, calcareous fubftances into quartz, and the whole mafs 

 of a mountain into inflammable or faline matter, or even 

 into ores, metals, or femimetals. To it I afcribe the power 

 of producing, preferving, and continuing to form the differ- 

 ent beds and mineral repofitories, which are found both in 

 primitive and flcetz mountains : finally, the effeCls which the 

 waters produce in filtering from above to below, and which 

 in their paffage through the different rocks may undergo 

 fome peculiar modification, appear to me the principal caufe 

 why this fermentation may aft with more force in one part 

 of the fame mountain than in another." 



Patrin, a celebrated French mineralogift, confiders the 

 changes taking place in the mineral kingdom, as effefted by 

 a procefs fomewhat fimilar to fecretion in the animal and 

 vegetable kingdoms, and afcribes a kind of mineral life to 

 the earth itfelf, differing perhaps as much from vegetable hfe 

 as the latter differs from that of animals. According to 

 this theory, each kind of mineral fubftance is capable of con- 

 verting maffes of mineral matter into its own peculiar nature, 

 as animals convert their aliment into flefli and blood. What- 

 ever may be thou.ght of this theory, we believe that thofe 

 who are moft praftically converfant with the various phe- 

 nomena and tranfmutations that occur in mines, will readily 

 admit that many changes are taking place, which cannot be 

 explained on any known chemical or mechanical principles, 

 and which bear a ftrong refemblance in their effefts to the pro- 

 cefs of fecretion. Nor can it, even in the prefent flate of che- 

 mical fcience, appear improbable that the different earths and 

 metals maybe converted into each other by natural proceffes. 

 The different beds of rock interfefted by metallic veins, are 

 themfelves metallic fubftances combined with oxygen ; or, in 



Vol. XXXVI. 



other words, all the rocks and ftrata which form the earthy 

 pai'ts of the globe, confift of oxygen combined with metaUio 

 bafes ; and as thefe metalUc bafes may perhaps be compounded 

 of the fame elementary parts united in different proportions, 

 the tranfmutation of one earth or metal into anothpr, may 

 be effefted by a fimple change in the arrangement of the 

 elementary molecules. 



The theory of veins propofed by Von Oppel, and in part 

 fupported and extended by Werner, fuppofes veins to have 

 been fiffures originally formed by the deficcation of moun- 

 tains, and the fhrinking in of the mafs. Thefe fiffures, 

 being open at the top, were afterwards filled with their con- 

 tents by metaUic folutione poured in from above. Moun- 

 tains, according to Werner, have been farmed by a fuc- 

 ceflive accumulation of different beds and layers, placed or 

 heaped over one another. " The fubftance of thefe beds was 

 at firft wet, and pofTeffed little folidity ; fo that when the 

 accumulation of matter had attained a certain height, the 

 mais of the mountain yielded to its weight, and muft confe- 

 quently have funk and cracked. As the waters which 

 affifted in fupporting the mafs began to retire, and lower 

 their former level, thefe maffes then loft their fupport, and 

 yielded to the aftion of their weight, opening, and falling to 

 the fide where the leaft refiftance was oppofed. The (blink- 

 ing of the mafs of a mountain produced by deficcation, and 

 ftill more the fraftures by earthquakes, and other fimilar 

 caufes, may alfo have contributed to th« formation of 

 fiffures. 



" The fame precipitation, which in tlie humid viay formed 

 the ftrata and beds of rock, furnifhed and produced the 

 fubjlance of veins. This took place when the folution, from 

 which the precipitation was formed, covered the exifting 

 rents, which were as yet wholly or partially empty, and 

 open in the upper part. Veins, whether confidered as 

 rents, or ars the fubftance conftituting the vein, have been 

 produced at very different times ; and the antiquity or re- 

 lative age of each can be eafily determined." 



Such, in Werner's own words, are the great outlines of 

 his theory, a theory which we conceive to be decidedly op- 

 pofed by all the moft ftriking appearances exifting in the 

 mineral kingdom, and equally oppofed to the fimpleft 

 known and acknowledged laws of nature. If metallic veins 

 were once open fiffures, filled by precipitations from a folu- 

 tion that covered the whole globe, with the highcft moun- 

 tains in which metallic veins are iound ; it is obvious that 

 thefe metallic precipitations would be moft confiderable in 

 the lower parts of the furface, in valleys and plains, where 

 the fluid muft have been much deeper than on the fummits 

 and fides of mountains. We ought, therefore, to find 

 thick beds of metaUic matter covering and incrufting the 

 low and level parts of the globe ; but nothing is more rare 

 than to find beds of metallic matter in low plains. Where 

 beds of metallic matter exift, it is always in comparatively 

 high countries, abounding in veins ; and it is much more 

 probable that the beds and veins were formed by local 

 caufes, and not from a folvent covering the whole globe. 

 The metalhc parts of this metalliferous ocean muft have 

 pofleffed the greateft fpecific gravity, and inftead of floating 

 on the top of the fluid, to be depofited in the fiffures of 

 lofty mountains, it would have delcended by the laws of 

 gravity, forming crufts of different degrees of thicknefs 

 from the bottom to the top, increafing downward. The 

 reverfe of this is the faft. It is principally in alpine dif- 

 trifts, and at enormous heights, that metallic matter is ac- 

 cumulated in the greateft abundance. It is in the heights 

 of the Cordilleras of Peru that the produftive mines of Po- 

 tofi are fituated : it is in the fame chain of mountains, more 

 4 T than 



