the Spheroidal State of Bodies., Sfc. 63 



experiment presents no difference, being made either with 10 

 kilogrammes of metal, or with 1000 kilogrammes. The sen- 

 sation which is felt is the same in either case, and this is 

 readily conceived, knowing the repulsive force of incandescent 

 surfaces which is opposed to the contact of any body. 



The finger or the hand is then isolated in the midst of the 

 mass in fusion, and thus preserved from the disorganizing 

 action of the incandescent matter. I repeat, that the mass 

 must be abstracted. 



There remain the two factors c, t. I will suppose, and it 

 is a sufficient approximation, that the value of c = 0'15, and 

 that of ^ = 1500 degrees, the temperature of the metal in 

 fusion; now the product of 1500 degrees x 0'15 = 225. Thus 

 the epidermis of the experimenter would only be exposed to 

 225 degrees of heat. Undoubtedly this is a respectable quan- 

 tity of caloric, but it is too high, as we shall see. 



There is no contact between the hand and the metal ; this, 

 in my estimation, is a fact positively established. If there is 

 no contact, the heating can only take place by I'adiation, and 

 it is enormous, it must be acknowledged ; but if the radiation 

 is annulled by reflexion, and it is so, it is as if it did not exist, 

 and, definitively, the operator is, so to say, placed in normal 

 conditions. 



I think that I have established, a long time ago, the fact 

 that water in the spheroidal state has the property of reflecting 

 radiating heat*, and that its temperature never attains that of 

 its ebullition ; whence it follows that the finger or the hand 

 being humid, cannot rise to the temperature of lOO'^ Centig., 

 the experiment not continuing long enough to permit the hu- 

 midity to evaporate entirely. 



To recapitulate what I have stated on this point, I say, — 

 in passing the hand into any metal in fusion, it becomes iso- 

 lated ; the humidity which covers it passes into the sphei'oidal 

 state, reflects the radiating caloric, and does not become 

 heated enough to boil. This is all. 



I was right then in saying at the outset, this experiment, 

 dangerous in appearance, is almost insignificant in reality. 



I have often repeated it with lead, with bronze, &c., and 

 always with the same success f. 



* Nouvelle branche de Physique, or Ijltudes sur les Corps a I'^^tat sphe- 

 roidal, pp. 24 et seq. and 13^2 et seq. See also our two letters to the Aca- 

 demie des Sciences, dated the 14th and 21st of July, 1845. In the places 

 indicated will be found the explanation of this phaenomenon. 



t The experiments on the cast iron were made in the foundry of M. Da- 

 vidson, atLa Villette ; and, on the bronze, in that of M. Nerat, Rue Pierre- 

 Levee. I am happy to have an opportunity of publicly thanking these 

 gentlemen for their kind assistance. 



