ON THE METALS OF EARTHS. 



101 



brilliant sparks% and leaving behind alkali and earth ; and 

 which hissed violently when thrown upon water, decom- 

 posing it with great violence. I examined the products in 

 two experiments, one on alumine, and one on glucine, in 

 which naphtha was introduced into the platina tube, to pre- 

 vent combustion ; the masses were very friable, and pre- 

 sented small metallic particles, which were as soft as pot- 

 assium, but so small, that they could not be separated, so 

 as to be more minutely examined; they melted in boiling 

 naphtha. Either a part of the potassium must have been 

 employed in decomposing the earths in these experiments, 

 or it had entered into combination witli them, which is un- 

 likely, and contrary to analogy, and opposed by some ex- 

 periments which will be immediately related. 



Supposing the metals of the earths to be produced in ex- Attempt to 

 periments of this kind, there was great reason to expect, ^j™ themt 

 that they might be alloyed with the common metals, as well 

 as with potassium. Mercury was the only substance, which 

 it was safe to try in the tube of ])latina. In all cases in 

 which the potassium waS in excess, I obtained amalgams 

 by introducing mercury while the tube was hot; but the 

 alkaline metal gave the characters to the amalgam : and 

 though, in the case of glucine and alumine, a white matter 

 separated during the action of very weak muriatic acid upon 

 the amalgam, yet I could not be entirely satisfied, that 

 there was any of the metals of these earths in triple com- 

 bination. 



Mixtures of the earths with potassium, intensely ignited Mixtures, of 



in contact with iron filings, and covered with iron filings in ® <?a'^ns, 

 ^ ' . » potassium, 



a clay crucible, gave much more distmct results. Whether and iron filings^ 



silex, alumine, or glucine was used, there was always a ^^^"^^'^ alloyi. 



fused mass in the centre of the crucible ; and this mass had 



perfectly riielallic characters. It was in all cases much 



whiter aud harder than iron. In the instance in which silex 



was used, it broke under the hammer*, and exhibited a 



crystalline texture. The alloys fi'oni alumine and glucine 



were imperfectly malleable. Each afforded by solution in 



* The pyrophorus from alum, which I have supposed in the last Homberg's 

 Bakerian lecture to be a compound of potassium, sulphur, and char- pyrophorus. 

 coal, probably contains this substance likewise. 



acids. 



