■fifi On the Nature of the Earths. 



oxides irreducible by any hitherto known process. This 

 opinion was first adopted with reference to barytcs, which 

 participates of tjie properties of both classes of bodies, and 

 was from analogy extended to the other members of the 

 two species. 



Very shortly after Lavoisier's Elemcns de Ch'imie were 

 published, some experiments, made at Schenmitz in Lower 

 Hungary, by Toudi* and Ruprccht, were given to the 

 world, by which it appeared that they had effected the re- 

 duction of barytes, magnesia, and lime. These results, the 

 translator of that work, Mr. Robert Kerr, introduced into 

 the second English cdifion, immediately succeeding the 

 speculations of Lavoisier above alluded to, and accompanied 

 them with some original remarks on the nature and ar- 

 rangement of physical bodies, which, as they are peculiarly 

 applicable to the present moment, I have thought proper to 

 transmit to you. 



He observes t : " These discoveries give reason to hope, 

 that chemistry may one day arrive at a most beautiful state 

 of simplicity. It is, perhaps, no improbable conjecture, 

 that all the bodies in nature may be referred to one class of 

 simple combustible elementary substances, to oxygen and 

 caloric; and that, from the various combinations of these; 

 with each other, all the variety produced by nature and art 

 may arise. The only knov/n difference between metals and 

 pure combustibles, as they are called, is in degrees of qua- 

 lities. They are all combustible j that is, they all combine 

 W\i\\ oxygen, though under different degrees of temperature; 

 and in diffeient states of saturation with that body form 

 oxides, which have alkaline % or acid properties." 



• Although KIaproth(i7) and Tihawski have called the accuracy of Toudi 

 and Runrecht's results into question, their objections do not affect the pur- 

 pose for which the experiments are here introduced. 



f Elements of Chemistry, vol. i. p. 265, fifth edit. 



I His opinion on tlxis subject received corroboration from some experi- 

 ments published in the Truniacthms oj' /he Turin Acadony, which gave reason 

 for supposing that soda was a modification of magnesia, this latter body 

 being, according to Toudi and others, a metallic oxide; and he concludes 

 vvitJi observing that, "from onalop;;/, we way presume polash to ic a metallic 

 sukituiue, in soo. » hilherto unknmvii stale nj' com !■! nation." 



(a) Annates de Chimie, torae ix, p. 55, 54. 



Such 



