Experiments on various Earths. f 165 



upon the clay of the crucible. In this respect barytes re- 

 sembles some rich oxides of iron, which are totally uncon- 

 fi nable in a clay crucible at a high temperature. 



After' making two hundred experiments without having 

 obtained, what I thought, a perfect globule or regulus of 

 pure metal, I abandoned the subject till new reasonings and 

 after-reflection should point out any new tract which was 

 likely to lead to more success. I was satisfied that I had 

 obtained an approach to metal, and was even convinced that 

 the metal at one part of the operation was more decidedly so 

 than it afterwards appeared to be when examined cold : but 

 I was not at all satisfied that the regulus I had obtained 

 was in its ultimate state of purity. 



Disappointed in my hopes of success with barytes, my 

 experiments on lime and strontian were few; but limited as 

 they were, I was convinced that thev were similar com- 

 pounds, and capable of decomposition. I did not succeed 

 in obtaining so compact reguli as with the barytes, but both 

 of them showed metallic crystallization upon the surface,, 

 although apparently more volatile and destructible than those 

 of barytes. 



Should I at any future time increase my experiments on 

 these substances, and should the results point to any thing 

 new and likely to be beneficial, I shall communicate them. 

 I am confident that an increased knowledge on the subject 

 of lime- stone will prove highly interesting to the manufac- 

 turer of iron. The single circumstance of its being a me- 

 tallic substance combined with oxygen, and as such acting 

 its part in the operations of the smelting furnace, will enable 

 him to explain facts that cannot be reconciled to any past 

 reasoning or knowledge on the subject. 



In regard to silex or clay, considered as metallic oxides, 

 I have been able to ascertain nothing decisive. They seem 

 not (judging from the experiments I have made) in the 

 most distant manner allied to the other three earths, though 

 thev may be more akin to each other. It is possible that 

 silex may prove to be clay completely deprived (or nearly so) 

 of all its moisture. Or, in other words, that clay, by fire or 

 other natural processes, becomes oxygenated to such an ex- 



L 3 tetit 



