300 Dr. SchafhaeutI on the Different Species of 



out setting the remaining parts of the compound in perfect 

 freedom, and enables them to replace the lost body by another 

 chemical equivalent, or to allow their molecules to follow their 

 own attractive tendency, and to form, after being set free, a 

 new individual body for themselves. 



The action of bodies in their utmost molecular division is 

 quite otherwise than when their molecules had been sufficient- 

 ly moveable to follow, after separation, their own mutually at- 

 tractive forces and to neutralize them in one centre. 



A body whose chemical force had been neutralized by an- 

 other, now deprived of that neutralizing body, without having 

 sufficient freedom of its molecules to follow their forces of 

 mutual attraction set at once at liberty, is in the state of a body 

 surrounded by an atmosphere of electricity and in a different 

 relation and condition of tension to the surrounding bodies. 



This relation is visible in all bodies placed under such cir- 

 cumstances in contact with others : the instance c^the reduc- 

 tion of iron at a low temperature by a current of hydrogen is 

 well known ; the following fact seems less so. A lump of mal- 

 leable, hammered, or rolled iron raised to a white heat, over 

 which water is poured, exerts a very feeble decomposing power 

 on the water. Let us now take a similar mass of iron out of 

 the puddUng fwrnace, just ready to be placed under the ham- 

 mer, and pour a basin of water upon it. No hissing noise is 

 perceptible, no generation of steam visible*, and the water is 

 at once decomposed, the flames of hydrogen enveloping the 

 white-hot ball and rising very often to a height of four or five 

 feet. I need scarcely remark, that the iron taken out of the 

 puddling furnace is in the same state as iron treated with 

 acids; a skeleton of each grain of cast iron remains, with this 

 diiference only ; that with iron treated with acid, electro-posi- 

 tive metals are partially removed from the compound; but by 

 treating cast iron in a puddling furnace, the relative electro- 

 negative bodies are taken instead, without destroying the me- 

 chanical texture. A few strokes of the hammer destroy this 

 property of the white-hot iron. 



When a constituent of a decomposed body is separated 

 from another, in a solid state, by chemical action, the so-sepa- 

 rated body is never left in the same state as that in which it 

 existed when forming a corresponding part of another body ; 

 and each body set at once free by chemical action, with per- 



* Onthe subject of the subitaneoiis formation of steam byred-hot orwhite 

 puddling slag, oxide of iron, and malleable iron, I mentioned some cu- 

 rious instances in my paper " On the conversion of water into steam at 

 the higher degrees of temperature," &c., in the Mechanics' Magazine, vol. 

 XXX. pp. 138, 294, and 339. 



