72 JOURNAL (J¥ THE 



freezing mixture of ice and hydrochloric acid and the carbon disul- 

 phide becomes turbid, while delicate cloud -masses form in the alco- 

 hol and if the alcohol contains more than 10 per cent, water, it be- 

 comes milky and opaque. These cloud-masses disappear above 

 -10^ or -9° c, but the temperature could.not be accurately fixed as 

 it seemed to depend upon the amount of carbon disulphide and 

 water held in suspension or solution. If the alcohol and disulphide 

 stand for some time, all disulphide apparently settles out as the 

 cloudiness cannot be again produced by cooling. Care was of course 

 exercised to prevent any agitation or mixing of the liquid layers in 

 sinking the tube into the freezing mixture. A mixture with ether 

 containing a small percentage of water gave also a turbid appear- 

 ance on being cooled, but the layers were not distinct, nor, on taking 

 the tube from the freezing mixture, did the cloudiness disappear so 

 easily as in the case of the alcohol. Experiments with it then could 

 not be so easily observed nor so rapidly repeated. 



The temperature of formation or decomposition given by Wartha 

 (-12° c.) needs additional data to make it correct, according to the 

 following experiments. Even when evaporation and the formation 

 of hydrate was rapidly going on in a shallow watch glass full of the 

 disulphide, the temperature of the liquid itself did not fall below 

 -6° c. For these experiments a Geissler thermometer graduated 

 to ^ degrees was used, the bulb was nearly spherical and from its 

 under-surface a small bead of glass projected. With this bead touch- 

 ing the surface of the carbon disulphide and the evaporation started 

 by blowing upon it for a short time, the incrustations soon covered 

 the bulb and the mercury sank rapidly to about O'^c. It then sank 

 very slowly. Seemingly more carbon disulphide was drawn uxDon 

 the bulb than was used in forming the solid, as the latter had an 

 oily appearance and this probably tended to keep up the tempera- 

 ture. If the thermometer was raised entirely above the liquid the 

 oily look disappeared, the tufts of the solid, before thick and short, 

 branched and grew stiff and strong while the mercery rapidly sank 

 to a constant point. To determine this point, then, the solid was 

 allowed to form over the bulb and some extra disulphide was taken 

 up. By a crank arrangement the thermometer was then raised sev- 

 eral inches above the surface of the liquid and the lowest temi^era- 

 ture reached noted. The stny at this point sometimes lasted one or 

 two minutes before the rapid rise commenced. If the thermometer 

 was blown upon whilst the mercury was sinking, the temperature* 

 could be reduced several degrees below the point of decomposition. 

 If the constant point had been reached and the mercury was beginning 

 to rise, even if only yV degree, blowing caused a very rapid rise and 



