314 Hartley — On the Conditions of Eqiiili1)riuni of Deliquescent and Hygroscopic 



On frequent occasions, generally every third day, the beakers were weighed 

 and the weights recorded opposite the columns containing the date and atmo- 

 spheric conditions during the preceding twenty-four hours. These observations 

 were continued from November 15th, 1899, to May 16th, 1900. It has not been 

 thought necessary to include here the atmospheric conditions for every day 

 during this period, but only on those days when the salts were weighed. In 

 four cases the salts completely liquefied, but cupric bromide remained almost 

 entirely solid, only minute drops of liquid being formed. The complete series 

 of temperatures and weighings of the difFerent salts, distinctly show that the 

 tension of aqueous vapour under the conditions of the experiments varied only 

 with the temj^erature, and was not sensibly affected by fluctuations of the 

 barometer. 



The air in the bell-jar had a humidity of generally over 85 per cent, of 

 saturation, and often over 95 per cent. It might be exjDected to be maintained 

 at saturation point, but as a matter of fact the deliquescent salts dried the air 

 more rapidly than the water could moisten it. 



Curves have been drawn showing the course of chemical change through the 

 whole period ; and the following tabulated statement of the weighings gives the 

 composition of the hydrates formed in solution : — 



HTDRATED COMPOUNDS FORMED. 



