AUoiropy. 



being twisted in spiral sticks, or formed into any required 

 shape. 



The proof that this peculiar condition is owing to latent 

 heat is very convincing. If a mass of moderately warm barley 

 sugar be taken and pulled out to double or treble its length, 

 then folded and pulled out again and again, it eventually loses 

 its transparency, becoming converted into penides, or pulled 

 sugar, as it is technically called. But to pass from the vitreous 

 condition it must get rid of its latent heat, and therefore, as 

 the change is accomplished, the whole mass throws out this 

 hidden caloric, becoming so hot that the hand cannot hold it. 



To return, however, to the elastic state of sulphur : this 

 condition may be rendered much more permanent by the addi- 

 tion of the minutest portion of iodine to the sulphur whilst 

 melting. The smallest particle of iodine renders the limpid 

 melted sulphur of a dark colour, and seems to be retained in 

 spite of the high temperature to which it is necessary to raise 

 the sulphur previous to pouring it into water. This iodized sul- 

 phur is much more elastic than that which has been fused and 

 cooled without the iodine. 



By many chemical authors this elastic sulphur is called 

 • sulphur, an absurd misnomer, inasmuch as plastic sig- 

 nifies that which can be moulded into any required form, cer- 

 tainly not a property of elastic sulphur ; and, misled by this 

 absurd title, one of the best known writers on chemistry states 

 that it is in this condition that sulphur is used for taking 

 ca-; 



These changes, though not all of which sulphur is capable, 



serve very well to show the remarkable allotropic changes of 



which many substances are susceptible. That the same body 



should, without any alteration of its composition, be able to 



:i the apparently opposite states of extreme brittlene - 



and high elasticity, of transparency and opacity, of solubility 



and insolubility, in octohedral and in prismatic crystals, in a 



f extreme limpidity and in one of great viscidity, is a 



rkable circumstance, and one worthy of being inves- 



.uch greater care than it has yet received. 



