( 463 ) 



e.g. when the temperature has descended to the ordinary tempera- 

 inre, the conversion X, — > S,j. will show its influence. 



So the liquid phase will disappear, which is attended by a dimi- 

 nution of volume and the solid phase moves from the line S^S.; 

 towards the left. If we begin to heat again before the line for the 

 internal equilibrium S.,S,^ has been reached, we shall reach the tran- 

 sition surface somewhere between S- and S.^, and at a temperature 

 below that of the unary transition point rhombic sulphur will be 

 converted to nionoclinic sulphur, which transformation is accompanied 

 by an increase of voluiue. In consequence of the continued conversion 

 of S,j,, however, which takes place in the mixed crystals, the total 

 concenti-ation will continuall}' shift to the left, which causes the 

 nionoclinic mixed crystal phase to disappear again with diminution of 

 volume after some time, in consequence of which the appearance of a 

 new nionoclinic phase cannot be found until at a higher temperature. 



The transition phenomenon will, therefore, be continually shifted 

 towards higlier temperatures, till at last the unary transition tempe- 

 rature is reached. The phenomena described here were observed in 

 a very distinct way and in the expected succession. As at about 85° for 

 the first time at constant temperature a very clear increase of volume 

 was observed, which was followed by decrease of volume, we are 

 justified in assuming that in this experiment the transition point had 

 been lowered by + 10°. 



That when starting fVoni sulphur perfectly free from 8y. we find 

 a too high transition point, as among others Gernez and Reichek 

 mention (97,6 and 97°), this too follows from fig. 2 and also from fig. 1 . 



The second part of our investigation concerned the lowering of 

 the point of solidification which can occur in consequence of a large 

 Sy-content obtained by rapid cooling of liquid sulphur heated to a 

 high temperature. This investigation was chiefly undertaken to find 

 out whether the point of solidification of the nionoclinic sul[)hur 

 remains constantl}' 111°, as soon as the solidifying i)hase contains 

 more than 47o Sv- To ascertain this seemed of great importance, 

 because if this was really the case, this would render the existence 

 of a region of non-miscibility highly probable. 



As vSoch's method, which we shall call the capillary method, was 

 not very promising in this case, we adopted a method analogous to 

 that of Smith and Hoemes with the application of the resistance thermo- 

 meter used at this laboratory, which indicates with exceedingly great 

 rapidity and clearness small variations of temperature down to 0,001°. 



Now it was, however, to be foreseen that we should meet with 

 peculiar difficulties during this investigation, for concerning a series 



