ALUMINOUS CHALYBEATE SPRING IN I. OF WIGHT. 5Q 



cated in a drying apparatus at the heat of 180°*, the solid entsleftby 

 mass weighed eighty-six grains. During the evaporation evaporation, 

 the same appearances were observed as have been already 

 related (in Sect. Ill, D,) a d the dry saline mass assumed 

 u pale greeni3h colour. On standing in the air, it slightly 

 deliquesced, and its colour became- somewhat darker. This 

 saline mass, though slowly evaporated, never assumed a 

 distinct crystalline appearance. 



2. 1 have stated before (Sect. II, d.) that some differ- 

 ence prevailed in the specific gravity of the several specimens 

 of the water which were examined. A similar want of uni- 

 formity was observed in regard to the quantity of solid iur 

 gredients, as will appear from the following statementf. 



Grains. 



The l9t specimen yielded 86* 



2d &2- 



3d 63-6 _ 



. f In the pint 



4th 80-4 I r . * 



, > of sixteen 



5th • 828 



,,,, 1 ounces, 



6th 77-2 



7th 84' * 



8th 78' 



644 



These eight results therefore give 80'5 grs dried at 180%, 

 as the average quantity of solid ingredients in each pint of 

 the water. 



* This is the heat I have usually employed for desiccation, because 

 it is that which is obtained by the water-bath which I use, and can 

 scarcely br raised higher by that apparatus. By a heat of 180° how- 

 ever, I generally mean some intermediate point between 170 and 180°, 

 for il is impossible to regulate the temperature with perfect accuracy, 



■f In the first of these trials, a whole pint was evaporated; but in 

 the subsequent ones, the quantity of water was diminished to eight, 

 six, and sometimes only four ounces, all of which, for the sake of 

 uniformity, I have reduced in the table to the common standard of the 

 pint. 



X This specimen I brought myself from the spring ; the others were 

 sent me in sealed bottles from the Isle of Wight. 



Sect. 



