ALUMINOUS CAALYBEATE SPRING IN I. OF WIGHT. $£ 



form, and, when separated and chemically examined, had 



all the properties of alum. 



5. With regard to the proportion of sulphate of alumine, Proportion of 



contained in the water, it will be seen, that by connecting sul P hate of 



• . i pi • • 11/ alumine. 



together the results of the experiments just related (1, 2,3), 



eighty grains of residue, or a pint of the water, yield 3'8 

 grains of alumine heated to redness, which, according to the 

 proportion of twelve parts of iginted alumine in one hun- 

 dred parts of crystallized alum*, would be equivalent to 

 31.6 grains of the alum in each pint of the waterj. 



Sect. X. Sulphate of Lime. 



1. Some of the former experiments (sect. Ill, d and g) Examination 

 had shown, beyond all doubt, the presence ofselenite; and for sulphate of 

 indeed, from the general composition of the water, lime 



could scarcely be supposed to exist in it in any other form 

 of combination. 



To ascertain the quantity of this substance, a variety of 

 methods was used, the principal results of which I shall 

 cursorily relate. 



2. It would have been in vain, in this instance, to have 

 applied, without any previous step, oxalate of ammonia, 

 the usual test of lime, in order to obtain an accurate esti- 

 mate of the quantity of lime present in the water; for as 

 oxalic acid also acts upon iron, some ambiguity would ne* 

 eessarily have occurred, Indeed that oxalate of ammonia 

 did not, in this case, react upon the lime in the manner 

 that it usually does, had been noticed, (sect. IJI, f, g) in 

 some of the preliminary experiments!, 



3, It 



* These are the proportions stated by Mr. Kirwan, and which I 

 obtained myself on a former occasion (See the Analysis of the Brighton 

 Chalybeate) 



\ It is scarcely necessary again to observe, that the sulphate of 

 alumine contained in the water does not appear to exist there in the 

 state of alum; but it is perhaps better to express the quantity of 

 alumine by the quantity of alum which it would form, as the crystallized 

 state of the salt affords a much more precise standard of comparison. 



f By adding a considerable quantity of oxalate of ammonia, and Iron precipi- 



concentrating the solutions by heat, the whole of the lime appeared tated with lime 



to be precipitattdj together with a portion of iron ; but in order to y oxa . a e °" 



i obtain 



