182 



iSew Phenomena in Chemistry. 



of variation than the ordinary compass needle. The 

 inertia is to be attributed to the assumption by the 

 magnetized steel of a certain portion of the weight or 

 specific gravity of the mercury. When this amalgam is 

 exposed to the oxidizing influence of the atmosphere, it is 

 gradually decomposed, carbon being liberated, and the 

 permanent magnetism vanishing, while iron amalgam re- 

 mains. This will also finally decompose, pure mercury 

 and ferrous oxide resulting. 



Another discovery that I may claim, is the direct amal- 

 gamation of cast-iron, even of the most brittle and highly 

 carburetted character. This was first effected by means of 

 a compound amalgam of potassium, sodium and "ammo- 

 nium " with water; but I have since found that a simple 

 amalgam of potassium or sodium is generally sufficient to 

 effect the result. The surface of cast-iron may be amal- 

 gamated by placing an electro-positive or active amalgam 

 upon it with water or an acid ; a true amalgam may be 

 similarly formed with filings. 



In the course of the experiments which led to this dis- 

 covery, it was my fortune to observe phenomena of an 

 extraordinary character. The usual brilliant surface of 

 mercury is produced when cast-iron is treated with the 

 electro-positive amalgam, and the iron is rapidly " cut " or 

 dissolved. The impurities of the iron, with considerable 

 carbon are released and form a black mud around the 

 button of amalgam. If at this moment, before all the 

 positive metal has been oxidized, the amalgam be removed^ 

 washed and allowed to stand, particles of amorphous 

 carbon will be seen to emerge and float upon its mirror-like 

 surface. Whence comes this carbon ; why was it not given 

 up before ? Has it been amalgamated ; and if so, has it not 

 a metallic character ? It has been suggested to me that 

 particles of undissolved iron, containing carbon, have 

 been carried bodily into the amalgam, and afterwards dis- 



