in the Isle of Wight, ^5 



4:th method. To evaporate to dryness a known quantity of the 

 water and to boll the residue in caustic potash, which will dissolve 

 the alumine and s'dicay both of which may be precipitated again by 

 muriat of ammonia.* Treat the residue, insoluble in potash and 

 supposed to contain Iron^ lime and magfiesia^ in the manner pointed 

 out in the 2d method. 



5th method. After having obtained by the preceding methods a 

 knowledge of the proportions of iron and earthy substances, and 

 formed an estimate of the nature and quantities of acids with which 

 they are united, to ascertain in a direct manner the quantities of acids 

 by their respective reagents, with a view to obtain a confirmation of 

 the preceding results. 



6th method. To boil a known quantity of the water in succlnat 

 of ammonia, till all the iroft and ahimhie are precipitated — -edul- 

 corate, precipitate and separate the alumine from the iron by boiling in 

 caustic potash. From the clear concentrated fluid, to separate the lime 

 by oxalat of ammonia, and the magnesia by pure ammonia ; to 

 evaporate the remaining clear fluid to dryness, and to apply a red heat, 

 in order to burn or volatilize any remaining portions of the tests used 

 in the processes above described. To re-rdissolve the residue in 

 order to ascertain by subsequent evaporation the presence and quan- 

 tity of sulphat and muriat of soda, f 



1th methods To boil a known quantity of residue of the water, 

 in alcohol, in order to ascertain what salts it may contain which are 

 soluble in that menstruum. 



boiling a known quantity of the solid residue in the neutral eirbonate of ammonia, 

 instead of applying this reagent to the water itself. 



* The mode in which the silica may be separated from the alumine, will be detailed in 

 a subsequent part of this paper. 



+ This process is liable to an objection which will be hereafter fully stated, namely, 

 that muriat of soda is decomposed by sulphat of ammonia at a high temperature* 



2f 



