556 



windows the desired observations were executed by means of a 

 telescope ; the height of ascension in the capillary tubes was read 

 npon a perpendicularly divided scale. The liquid salt in the surround- 

 ing bath was continually stirred ; an arrangement was made to 

 prevent as much as possible the annoying currents of hot air circu- 

 lating before the windows. 



In all these experiments it was stated very soon, that the investi- 

 gated salts, when melted in the glass-tubes and on cooling again 

 solidifying therein, made the tubes in most cases crack ; or at least 

 they appeared on renewed heating to get soon unsuitable and badly 

 damaged, thus a substitution of the tubes by new ones being necessary 

 after each experiment. 



After many attempts, the tubes were arranged finally in the fol- 

 lowing way, to prevent this effect. ^45 (fig. 1) is a tube of '/f?ifï heavily 



fusible glass, which has a conical nar- 

 rowing at a, and a sideway tube e 

 with stopcock d ; the wider tube can 

 be closed at its upper end by means 

 of a stopper h, provided with the 

 stopcock C. Just above the round 

 bottom of the tube B, a small plati- 

 num crucible T of about 1 ccm. 

 volume, hangs between three strong 

 horizontal platinum-wires ; they are 

 either melted into the glasswall of 

 the tube, or they can be fixed to a 

 platinum-ring, supported by three 

 elevations in the wall of the tube. 

 If in the last mentioned case the 

 tube B at the same time is arranged 

 in such a way, that e.g. just below 

 e the two parts of it can be put 

 together by means of a ground col- 

 lar, it will thus be possible eventu- 

 ally to take the platinum-ring easily 

 from the tube, and to restore it again 

 after thoroughly cleaning the different 

 parrs of the apparatus. In every case 

 the platinum-crucible T needs to be 

 fixed into the tube as centrally as 

 possible. The narrowing at a is ground 



B 



Fig. 1. 



