530 Prof. Magnus on the Allotropic Conditions of Sulphur. 



portment of sulphur in a similar manner; for if sulphur be 

 coloured intensely red or black by one of the above substances, 

 for which only 0'0003 of its weight of parafiine is necessary, 

 and if it be then suddenly cooled, either by pouring it in cold 

 water or on a glass plate, it remains for a long time so soft and 

 greasy that the individual parts of it can be joined together and 

 united into one piece. It may then be drawn out in long thin 

 threads, and retain this adhesive state for several hours, often 

 even for a day, — a comportment which I have also already 

 described in the black sulphur. 



But not only the manner of solidifying is altered by this small 

 admixture, but also in the liquid condition does this sulphur 

 exhibit a different comportment to the ordinary sulphur; for 

 it is viscid indeed at a higher temperature, but much less so 

 than common sulphur. 



Since the soft and greasy condition of the black sulphur 

 arises from the admixture of so small a quantity of a foreign 

 substance, it is also probable that the flexibility and elasticity 

 of the yellow so-called soft sulphur results from the small 

 quantity of crummy sulphur which it contains. 



Such changes in the properties, by the presence of small 

 quantities of foreign substances, are indeed not frequent ; yet is 

 an example not wanting, and we only need to be reminded, in 

 this respect, of the change of iron into steel. 



The various allotropic conditions of sulphur are hence the 

 following : — 



1. Prismatic sulphur. 



2. Octahedral sulphur. 



Both soluble in bisulphide of carbon. 



3. Insoluble sulphur. 



4. Crummy sulphur, which in the fresh state is soluble in 

 bisulphide of carbon, but once separated from it does not again 

 dissolve in it. 



This has been hitherto described by me as soluble and inso- 

 luble red sulphur. For if soft sulphur contains even the smallest 

 quantity of colouring substance, it remains constantly with the 

 crummy sulphur, because, like this, it is more soluble in bisul- 

 phide of carbon than common sulphur, and hence remains behind 

 with it in the mother liquor, and also, on the complete removal of 

 the bisulphide of carbon, adheres to it in the sohd form. 



5. The black sulphur, which, since it results from an admix- 

 ture of foreign substances, cannot indeed be considered as an 

 aUotropic condition, but as an especial modification of sulphur, 

 because it is distinguished from the various conditions of sul- 

 phur not only by the colour, but also by the above-mentioned 

 properties. 



