Prof. Magnus on Red and Black Sulphur, 188 



To obtain red sulphur of a beautiful colour it must be broken 

 into pieces of tolerable size before it is completely hardened. If 

 this is not done it will be long before it becomes solid, and its 

 colour is then less beautiful and more orange. If this method 

 is adopted the sulphur has a cochineal or sealing-wax colour, 

 and forms a porous heap of separate amorphous granules. 



When red sulphur has once become solid it is no longer 

 soluble in bisulphide of carbon; it is also little, or not at all, 

 soluble in alcohol, aether, benzole, and oil of turpentine, though 

 rather more so in chloroform. 



That this sulphur, although obtained from a solution of bisul- 

 phide of carbon by the evaporation of the latter, will not dissolve 

 again in bisulphide of carbon is certainly remarkable, though 

 not without analogy ; for silicic acid, after being dried at a high 

 temperature, is no longer soluble. Inasmuch as remelted as 

 well as tempered black sulphur contains yellow as well as red 

 sulphur, it appeared probable that the solubility of red sulphur 

 depends upon the presence of yellow. If red insoluble sulphur, 

 however, be washed with bisulphide of carbon which already 

 contains yellow sulphur in solution, it will be found to be as 

 little soluble in it as in pure bisulphide of carbon. When finely 

 powdered, red insoluble sulphur is mixed with yellow, and the 

 mixture fused, a part of the red becomes soluble, but not more 

 than if the red, without the addition of yellow, had been melted 

 at the same temperature. By fusing the red, in fact, a part 

 becomes converted into yellow sulphur ; and it would appear as 

 if the intimate mixture of both kinds of sulphur which is thus 

 produced were alone soluble in bisulphide of carbon : not merely 

 because a combination of both has been formed, but because the 

 red sulphur in this mixture is more thoroughly distributed. So 

 distributed, it is soluble ; but when its particles lie close together, 

 it ceases to be soluble in bisulphide of carbon. Hence it hap- 

 pens, that when a solution of red sulphur contains yellow, and 

 all the bisulphide of carbon has been withdrawn before the yel- 

 low sulphur has had time to crystallize, the solid mass is partly 

 soluble again, and gives a red solution. We may therefore assert 

 that all solutions of red sulphur are mixtures of red and yellow* 

 If such a solution contains little red and much yellow sulphur, 

 then on evaporating, crystals are formed which, if apparently 

 red, are yet soluble; they evidently owe their colour to 4he 

 mother-liquor which they enclose. If the solution contains 

 much red and little yellow sulphur, the crystals are soluble with 

 the exception of a residue of red sulphur. This residue, how- 

 ever, is not so red as that which is obtained after all the yellow 

 sulphur has been separated by crystallization ; it is more yellow- 

 red, and sometimes even yellow. This difference in colour evi- 



