164 Experiments on various Earths. 



I next varied the experiments in the following manner: 

 Iron ore was de-oxygenated almost to a state of metallic pu- 

 rity. The ore in this state consisted of 90 parts of iron, 

 with which a little oxygen was si ill combined, and 10 parts 

 of calcareous earth. 



XXTII. — 280 grains of this ore, and 2S0 grains of carbo- 

 nate of barytes were fused together, and the result was as foK 

 lows: A double stratum of the reguline matter was formed; 

 the upper evidently more metallic than that below ; yet the 

 general appearance of this was less metallic than the results 

 of Exper. XXI and XX [I. The button of iron was covered 

 on its surface with a silvery- white circle delicately crystal- 

 lized in the starry form peculiar to the barytium ; and this 

 being the first crystallization of that form I had ever seen cni 

 iron, I was led to infer that an alloy had taken place be- 

 tween the iron and the metal of the barytes. The, weight of 

 this button was found to be 172 grains. Loss lOS^rains 

 of matter, which, taken at the rate of 90 per cent, of metal 

 in the ore, gives the quantity of iron oxidated by 280 grains 

 of barytes 97 T V grains, or 34-/V grains of iron from 100 

 grains of carbonate of barytes, a result but little different 

 from the last experiment. | 



Similar experiments were performed with various propor* 

 tions of the barytes and de-oxygenated ore; and correspond- 

 ing results were obtained. When the iron existed in equal 

 portions to the barytes, a quantity of crystallized regulus 

 was obtained nearly equal to one half of the result — the 

 other half being always a blaek glass. When a greater pro- 

 portion of iron filings was used, and' to the extent of two 

 parts to one of the barytes, a greater proportion^ the re- 

 gulus was obtained ; but then the experiment was difficult to 

 manage, from the great heat necessary to fuse so large a re- 

 lative proportion of malleable iron, without destroying the 

 barytes altogether. On the contrary, when the carbonate of 

 barytes or pure barytes were used to the extent of two parts 

 to one of iron filings or oxidated iron, the mass was chiefly 

 resolved into a glass, and the greatest part of the iron was 

 oxidated : the quantity of regulus small, and a perfect re- 

 sult always precarious, from the violent action of the barytes 



upon 



