80 Intelligence and Miscellaneous Articles. 



negligible fraction of a degree : the highest of them is taken for the 

 solidification-temperature of the substance, applying to it the cor- 

 rection arising f rom the circumstance that the whole of the stem of 

 the thermometer is not bathed by the liquid. 



I have turned to account the precision which this process permits, 

 especially to elucidate the various peculiarities presented by the 

 change of state of sulphur ; and the following are the chief results 

 at which I have arrived : — 



The most simple results is that which relates to sulphur insoluble 

 in sulphide of carbon, obtained by exhaustion from flowers of 

 sulphur. The solidification of this variety takes place at 114°-3 C, 

 whatever may be the temperature at which it was melted : thus, in 

 all the experiments, I have not found more than T \ of a degree 

 difference between the temperature of solidification of the sulphur 

 which had been brought to ebullition and that at which the same 

 substance solidifies after being heated to 170° only, or even 121°. 



This constancy of the solidifying-point is not found in the other 

 varieties. For octahedral sulphur the temperature of solidification 

 is higher when it has been fused at the lowest possible temperature 

 — for instance, at 121° ; in this case it reached 117 0, 4. If the 

 liquid has been heated to 144°, it is only 113°*4; it descends to 

 112°-2 for the sulphur kept five minutes at 170° (which renders it 

 very viscous, and, according to AT. Berthelot's experiments, produces 

 the maximum of insoluble sulphur). Starting from this value, the 

 temperature of solidification rises rapidly to 114°-4, the solidifying- 

 point of the sulphur which has been heated to various temperatures 

 between 200° and 447°. This last value is sensibly the same as 

 that which corresponds to the solidification of the insoluble sulphur. 



In regard to prismatic sulphur, its temperature of solidification 

 depends on its previous state. If it comes from insoluble sulphur, it 

 behaves like this ; nevertheless, when it is submitted to several 

 successive fusions and solidifications, not much exceeding the fusing- 

 temperature, the solidifying-point may rise more than one degree. 

 In like manner, if it comes from octahedral sulphur its solidifying - 

 temperature depends on the temperature to which it has been 

 brought. Thus, if it comes from sulphur heated to 170° (the 

 solidifying-point of which is 112°-2), and has been liquefied at 

 about 120° or 123°, the temperature of solidification rises gradually 

 each time, and after a sufficient number of fusions and crystalliza- 

 tions it becomes equal to 117 0, 4. 



Soft sulphur, flowers of sulphur, and roll sulphur conduct, as 

 might have been expected, to results intermediate to those which I 

 have noted for insoluble and octahedral sulphur, both of which 

 enter into their constitution. 



These peculiarities account for the diversity of the numbers given 

 for the temperature of change of state of sulphur by observers whose 

 skill there is no reason for calling in question. They also show how 

 tenacious are the modifications resulting from the tempering of 

 sulphur, since, in order to cause their disappearance, a considerable 

 number of successive fusions and crystallizations are necessary. — 

 Comptcs Rendus de TAcad. des Sciences, vol. Ixxxii. pp. 1151-1153. 



