455 



is satisfactory; the maximum error in the value of *; amounts to 

 57oo ; for 14 of the 22 observations the deviation is even smaller 

 than 1V„„. 



When we calculate the point of intersection of the two lines, we 

 find 184.5° for the transition temperature. In my opinion this value 

 can only depart a few tenths of degrees from the real point Oi 

 transition. 



In these experiments the ti'ansition point could not diiectly be 

 determined optically ; I have thought only a few times that I could 

 detect a difference in tlie appearance of the crystals above and below 

 the transition point. 



6. Tlin'mic determmation of the transition point of ammonium 

 chloride by means of catalysts. 



After the determination of the transition point from the solubilities 

 in water I have resumed the original thermic determinations, and 

 I have tried to find catalysts which can annul the retardation in 

 the conversion at the point of transition. For this purpose I have 

 looked for substances which are liquid at the transition point, and 

 of which it could be expected that they react only little, if at all, 

 to ammonium chloride. The number of available substances is not 

 large; glycerine is very suitable for this purpose. A quantity of 

 ammonium chloride was uniformly moistened in a mortar with a 

 few dro])S of glycerine, and conveyed to a test tube. By placing 

 this in an oilbath above the point of transition and then in a bath 



NH, Ct 



JttwnrUU. list- lêQj 



W-UAxrUilJi-ljr/ 



Tvmt in mlnuits. 



Fig. 2. 



