DECOMPOSITION BY HEAT. 109 



inquiry, has recently proved that the moisture upon the 

 skin is sufficient to protect it from disorganization, if 

 the arm is plunged into baths of melted metal. The 

 resistance of the surfaces is so great, that little elevation 

 of temperature is experienced.* Professor Plucker, of 

 Bonn, has stated that by washing the arm with ether 

 previously to plunging it into melted metal, the sensation 

 produced, while in the molten mass, is that of freezing 

 coldness. 



We have now seen that heat at different degrees of 

 intensity appears to produce chemical composition 

 that it decomposes combined elements that it alters 

 the conditions of bodies, and actually maintains so 

 powerfully a repellent force, that fluids cannot touch 

 the heated body. More than this, it exerts a most 

 powerful antagonistic influence over all chemical rela- 

 tions. If, to give one example, the volatile element 

 iodine is put into a glowing hot capsule, it resolves itself 

 immediately into a spheroid. Potash rapidly combines 

 with iodine ; but if a piece of this alkali is thrown upon 

 it in the capsule, it also takes the spheroidal form, and 

 both bodies revolve independently of each other, their 

 chemical aflinities being entirely suspended ; but allow 

 the capsule to cool, and they combine immediately. 

 Science teaches us that a temperature so exalted as not 

 to burn organic bodies may be produced, and points to 

 iis this remarkable fact, that the destructive limits of 

 heat are measured between certain degrees beyond 

 which a fire, by reason of its intensity, ceases to 

 develope heat. What is the radiant force into which this 

 principle changes? 



The experiments of Cagniard de la Tour and of 

 Boutigny (d'Evreux), connect themselves, in a striking 



* Some Facts relative to the Spheroidal State cf Bodies, Fire 

 Ordeal, Incombustible Man, tyc. : by P. H. Boutigny ( v d'Evreux), 

 Philosophical Magazine, No. 230 (third series), p. 80 ; Comptes- 

 Rendus, May 14,, 1849. 



