REPORT ON MINERAL AND THERMAL WATERS. IS 



Hermann* shows, that in the brine springs of Halle the quan- 

 tity of muriate of magnesia has gone on progressively increasing, 

 and that of the muriate of lime diminishing, since 1798, whilst 

 in those of Schonbeck the sulphate of soda each year has under- 

 gone a diminution. 



With respect to our own mineral waters, there is a general 

 impression, that the aperient springs, which rise so abundantly 

 from the lias, become weaker when long drawn upon, and it is 

 only in this way that I can reconcile the extreme discrepancy 

 between the analyses of the same spring, at periods not very re- 

 mote one from the other. 



Bischof remarks, that in some cases different results may have Mode of ac- 

 been obtained, owing to some variation in the circumstances counting for 

 under which the water had been drawn. tion/^"* 



Supposing the well to have been just before exhausted, the 

 water obtained ought not to be expected to be so sti'ongly im- 

 pregnated as in common, because time had not been allowed for 

 that which had flowed in since to obtain its full complement of 

 saline ingredients. 



In this way he accounts for a discrepancy, between the quan- 

 tity of sulphate and of muriate of soda, which he detected at 

 Roisdorf in September 1824, and in April 1825 ; and on the 

 same principle we may explain, why the Pyrmont water was 

 found to be more strongly impregnated before the season of 

 taking the waters, in May, than during June and July, the 

 months of fashionable resort. 



I may add, that if we suppose the respective salts to require 

 different times for their solution, it may be seen, why in some 

 cases the relative proportions uf the saline ingredients have ap- 

 peared to varj'^, whilst the total amount continued as before ; for 

 if, owing to the well having been just before much drawn upon, 

 the salts which required the longest time for their solution ex- 

 isted in the water in a smaller proportion than usual, that very 

 circumstance might enable the water to dissolve a larger quan- 

 tity of the remaining ones, so as to make good the deficiency, 

 and to render the total amount of fixed ingredients nearly the 

 same as usual. 



Considering, therefore, the great uncertainty that exists with Method of 

 regard to this point in most cases, and the progressive condition ^f^^"^™;" 

 of chemical analysis, which renders the results obtained at one question. 

 period scarcely capable of accurate comparison with those of a 

 succeeding one, it were to be wished, that at each of the more 

 important mineral springs samples of the water were preserved 

 in bottles, hermetically, or at least very closely, sealed, to be 



• Bischof, p. 334. 



