339 



being continually shaken was cooled down to tlie ordinary tempe- 

 rature to make the action of the two layers as complete as possible 

 If' any liquid sulphuretted hydrogen had been distilled over, it was 

 always poured hack into A by tilting of the apparatus. When in 

 this way the cooling down lo i-oom-tomperatui-e had been achieved, 

 the apparatus was left for a few days to piomote the action. 



To make vapour pressure determinations bulb A was cooled in 

 liquid air, the apparatus was opened at C, and connected to the 

 tube D of the apparatus represented by fig. 4 by means of india 



c 



B 



(Ü) "^ 



v^ 



Fig. 3. Fig- ^• 



rubber. By exhaustion through tap /. with a waterjet airpump ilie 

 sidphuretted hydrogen-air mixture was partially removed from /> 

 and C (fig. 3); the i-est of the gas was absorbed by the cooled 

 cocoanut carbon /< by opening of / (after L had been shut). When 

 the gaseous sulphuretted hydrogen had entirely disappeared f lom the 

 apparatus, air was admitted, and the apparatus of fig. 3 was fused 

 to that of fig. 4 at D. Then the apparatus was again evacuated, the 

 liquid air round A was replaced by carbonic acid and alcohol, and 

 the sulphuretted hydrogen was sucked otf througli L. After the 

 liquid sulphuretted hydrogen had been removed from A by boiling, 

 the apparatus remained in connection with the waterjet pump for a 

 few hours more in order to remove the sulphuretted hydrogen ab- 

 sorbed in the solid substance as completely as possible. Then bulb A 

 was again placed in liquid air, the apparatus was completely evacuated^ 

 by the aid of the cocoanut carbon, air was admitted, tube F 

 was temporarily opened to convey mercury into E, and the whole 

 apparatus was exhausted again. 



The mercury in E was freed from air by heating in vacuum. 

 Aftei- the mercury had been cooled, A was again placed in carbonic 



