314 Harriry—On the Conditions of Equilibrium of Deliquescent and Hygroscopie 
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 temperature, 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 expected 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 :— 
HYDRATED COMPOUNDS FORMED. 
Formuna. ToraL WEIGHT OF HypRATE. | ForMutLa. ToraL WEIGHT or HypDRATE. 
Original Salt, Calculated. Observed. Original Salt, | Calculated. Observed. 
CuCle:2H20. Grs. Grs. | CoBr2"6H20. | Grs. Grs, 
GHOLSELO, o olf esl | WoOTé '| CoBr,;16H,0, .| 10°394 | 10-444 
CuCl,4H,0, . .| 8688 | 8-416 Not formed. || CoBr,17H,0,  . | 10-764 | 10°720 to 10-770 | 
|| CoBry18H,0, .| 11°182 | 11:145 to 11:136 
Chalgeined Peeks, Carte | CoBr;:19H,0, .| 11°502 | 11:379 Notformed. 
CuBr,2H,0, . ./| 13:500 | 18°576 
CuBr,°3H,0, . .| 14:488 | 14:4854 
Original Salt, 
CuBr,4H,O, . .| 15:287 | 15°334 to 15:383. NiBr2*6H20. 
NiBr."18H,0, .| 12°754 | 12°762 to 12°760 
Original Salt, 
CoCl2*6H20. wen 
\ . 6 of riginal Salt, 
CoCl,8H,O, . .| 4240 | 4-277 SEG) 
CoCl,10H.0,. . 4:906 5°035 WHECIOIELO, o « 4:600 4:593 to 4°6138 
CKoCHLenMELO, o « 5°187 5:246 to 5:186. Nil,:21H,0, . .| 4:926 4°932 to 4:938 
| 
CoC OE Ose 5°472 | 5°254. Not formed. || Nil,23H,O, . . 5183 | 5:191 to 5:2038 
