McClenahan — Hydrous Thallic Chloride. 



109 



In the series of experiments next recorded, another prepara- 

 tion of the hydrous thallic chloride was dehydrated at various 

 fixed temperatures in air or in hydrogen chloride, the loss of 

 weight after a definite interval was noted, and the chlorine 

 determined gravimetrically in the residues. The details of the 

 experiments are given in the following statement. The course 

 of dehydration in air and in hydrogen chloride and the action 

 of hydrogen chloride upon the salt are represented in the 

 diagram. 



It is to be noted in the first place that although the prelim- 

 inary analysis indicated a composition of the preparation of 

 the hydrated thallic chloride used in these experiments, the 

 close correspondence with the symbol T1C1 3 *4H 3 0, there is an 

 apparent slight gain in the chlorine contents of the chloride 



























































































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when heated in air nearly throughout the series. This is prob- 

 ably due to an incipient dehydration of the salt before it was 

 weighed out for the work, and the slight deficiency in the total 

 amount of water generally found points in the same direction. 

 Inasmuch, however, as it is a comparison of the behavior of 

 the salt in air with its behavior in an atmosphere of hydrogen 

 chloride which is to be studied, this trifling variation from 

 normal constitution is not important. 



It is manifest that the hydrous chloride takes on hydrogen 

 chloride in some degree in an atmosphere of that gas at all 

 experimental temperatures below 100°, and this is without 

 doubt due to the tendency of the salt to form under the con- 

 ditions of the chlorthallic acid observed by Meyer. At tempera- 

 tures below 50°, the loss of water in an atmosphere of hydrogen 



