INTRODUCTION. 3 



TINCT from ANY of the GASES already ESTABLISHED as 



ORIGINAL ELEMENTS. 



Now, unless such is the case, how can a body be entitled to 

 the term of ORIGINAL ELEMENT ? 



It will probably be found that in many of these experiments 

 the bodies so termed have been unavoidably subjected to high 

 heats in the dry or igneous process, or submitted to electric or 

 galvanic applications, and that the RESIDUUM, ALONE, or in 

 CONJUNCTION with a re-agent of known composition, used as 

 auxiliary, has probably laid such claim to the notice of the 

 operator, in the production of some novel result, that the por- 

 tion dissipated in the process, or what may have passed off 

 in a radiant form, has totally escaped cognizance, and has 

 never been taken into consideration. This is not an imputa- 

 tion against the operator, whose views have been totally directed 

 to positively tangible, or evidently material RESULTS. 



Thus, in the experiments in proof on carbon to entitle that 

 substance to the denomination it at present possesses, of an 

 ORIGINAL or UNDECOMPOUNDED body, it is stated that CHAR- 

 COAL and the DIAMOND, when ignited in oxygen gas, are con- 

 sumed, and the result is carbonic acid gas ; that charcoal, or 

 pure carbon, per se, when ignited in close vessels in vacuo, is 

 not reduced except in volume, but rendered more condensed, 

 and of an intense black colour. Sir H. Davy found that the 

 diamond yielded a volume of carbonic acid gas equal to the 

 oxygen consumed ; that charcoal and plumbago, under similar 

 circumstances (the latter an acknowledged compound}, yielded 

 carbonic acid gas, with a minute portion of hydrogen. 



What allowance has been made, in the operations on the 

 diamond, for the oxygen and hydrogen in their relative pro- 

 portions forming the water of crystallization, or for what has 

 passed off in a radiant state ? None. 



In the various systems which have been proposed on the 

 subject of Light, in explanation of its numerous and interest- 

 ing phenomena, however the eminent authors with whom they 



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