CHEMISTRY. 193 



separate aluminium from oxygen, yet when the metal is once pre- 

 pared, it exhibits no disposition to reunite with that element. 

 It does not decompose water, and does not readily tarnish in the 

 air. It will not form an amalgam with mercury, but is converted 

 by mercury into a modified condition, in which it oxidizes with so 

 much violence as to glow and burn the hand. Dr. Wurtz showed 

 that, contrary to common belief, aluminium absorbs pure quick- 

 silver with avidity, just as lead will absorb it, and a piece of rolled 

 aluminium sheet rubbed with mercury is split into its component 

 laminae. The internal surfaces of aluminium thus enfilmed with 

 quicksilver possess properties altogether different from the usually 

 passive metal. On exposure to the air, they at once take fire 

 spontaneously, and burn with evolution of heat. A coating of 

 hydrate of alumina appears on the surface of the foil in a bulky, 

 feathery mass, with a growth so rapid as to be visible to the naked 

 eye. Aluminium foil, which, in its ordinary condition, will not 

 oxidize in the air, when rubbed with mercury is converted into an 

 active metal, and seizes oxygen so rapidly as to take fire and burn 

 spontaneously. 



The author of this important discovery founds upon it a new 

 theory of aluminium. He considers ordinarily aluminium to be in 

 an electro-negative or passive state, like what is known as passive 

 iron, and that quicksilver induces an electro-positive or active 

 state, in which latter condition it resembles sodium or potassium. 

 His experiment showed that no amalgam of aluminium is formed, 

 but that the quicksilver is merely absorbed beneath the outer crust 

 of the metal, and this phenomenon he believes to be analogous to 

 the celebrated lead-syphon experiment of Professor Henry, in 

 which quicksilver was slowly conducted through the pores of the 

 lead, bent in the form of a syphon, as water would be conducted 

 through a syphon tube. 



Dr. Wurtz's deductions from his new theory are of great inter- 

 est and importance. He holds out the idea that we may confi- 

 dently hope to obtain iron in a passive form, a discovery the im- 

 portance of which in all departments of the arts can scarcely be 

 exaggerated. Iron in this state would not corrode or rust, and 

 could be applied to many purposes for which it is not now avail- 

 able. We may also some day obtain sodium and potassium in a 

 passive state, so as to handle and expose them just as we now do 

 aluminium. If a metal can be converted from a passive to an ac- 

 tive state, why not from the active to the passive ? 



The interesting discovery of Dr. Wurtz opens the door to an 

 extensive field of research, and will attract the attention of scien- 

 tific men everywhere. New York Post. 



WHOLESOME WATER. 



The exercise of common sense in the investigation of the con- 

 ditions to which water has been exposed, aided by the results of 

 analysis, and some knowledge of physiological investigations and 

 the laws of nature, will lead to the following conclusions with 

 reference to this matter : 



