( 465 ) 



tlie beginning, and that a tendency can be observed durbhi the soli- 

 dification to reach the unary temperature of solidification. As, how- 

 ever, the convergence temperature lies too low for this in these 

 experiments, and the degree of ujidercooling with resjiect to the unary 

 point of solidification is too great, this latter temperature cannot be 

 reached. 



Already in these first experiments we got the impression that we 

 must not ascribe any greater importance to the temperature 111° 

 than to any other point between 111° and 114°, 6, but that the lowest 

 point of solidification that can be found by this method of working, 

 is about 111°, because we do not succeed in obtaining a solidifying 

 liquid with a greater /SVcontent than corresponds with this point of 

 solidification. 



It really appeared that if we modify the expei'iment somewhat, 

 still lower points of solidification can be observed. This modification 

 consisted in this that the sudden cooling is brought about by pouring- 

 out the sulphur in a thin layer on a china dish. The crystallised 

 mass was then detached from the dish and put in the melting point 

 apparatus. After the resistance thermometer had also been placed in 

 it, the mass was quickly but cautiously melted, after which the 

 vessel Avas again placed in the bath of constant high temperature, 

 which was now kept at 106°, just as in the preceding set of expe- 

 riments. The temperature of solidification rose after grafting Avith 

 monoclinic sulphur to 109°, and remained constant for a time, after 

 which it fell again. When then the solidified mass was melted cautiously 

 again and the liquid had again been made to solidify, we observed 

 the temperature of solidification at 112°. Another observation, in 

 which pure S-j. was started from, yielded the temperature of solidi- 

 fication 108° at first solidification. It appears very clearly from these 

 experiments that the rate of conversion of S,j. in the two phase system 

 Sm -\- L, by which is meant monoclinic mixed crystals and liquid, 

 speciall}' when this system is very metastable, is much quicker than 

 was supposed, and that it is most likely owing to the increase of this 

 rate of conversion with the metastability that it is so exceedingly 

 difTicult to realise considerable lowerings of the point of solidification. 



As the phenomena described here seemed to deprive the assumption 

 of a region of non-miscibility of an important support, we now 

 examined whether the phenomena observed for liquid sulphur neces- 

 sarily point to the existence of an unmixing in the pseudo-system. 



For this purpose we heated sulphur in glass tubes of different 

 diameters resp. of 20, 16, and 5 mm. to a high temperature, and 

 then cooled it, sometimes rapidly, sometimes comparatively slowly. 



