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XXX. On the Presence of Organic Matter in the Purest Waters from Terrestrial 

 Sources. By ARTHUR CONNELL, Esq., Professor of Chemistry in the University 

 of St Andrews. 



(Read 17th April 1843.) 



EVER since the discovery by BERZELIUS of crenic acid in the iron ochre of the 

 water of Porla, in Sweden, chemists have admitted the usual presence of that acid 

 in mineral waters, or those springs containing notable quantities of dissolved in- 

 organic constituents. In such natural waters, also, as are visibly coloured, orga- 

 nic matter is usually understood to be present. Any ideas, however, which may 

 have been entertained respecting the occurrence of organic matter in the per- 

 fectly colourless, transparent, and comparatively pure water of ordinary springs, 

 wells, and rivers, have been merely vague and conjectural.* 



There is a simple experiment, which must have been familiar to most che- 

 mists, viz., that when a solution of acetate of lead is added to the water of springs, 

 wells, and rivers, a more or less dense white cloud is almost invariably formed. 

 This reaction, so far as I know, has been commonly attributed to the presence of 

 inorganic salts, such as carbonates, sulphates, and muriates. No doubt, where 

 these salts are present, in sufficient quantity to affect the lead solution, they will 

 produce their proper agency ; but, having often been struck with the much more 

 marked effect caused by this reagent in such waters, than by the other ordinary 

 tests of the common impurities in such sources, I was led to suspect that the 

 effect must be usually due, in whole or in part, to some other cause ; and a very 

 little investigation soon satisfied me that this was the case. The ordinary cir- 

 cumstances attending the reaction, I find to be as follows : The precipitate by 

 acetate of lead is formed even after the water has been boiled for some time, and 

 is then soluble without sensible effervescence, if a drop or two of an acid is added 

 immediately. The absence of effervescence may be noticed with a lens in a large 

 test-tube ; or by allowing the precipitate to subside in a well corked vessel, and then 

 acting on it by acid. These facts shew that it cannot be due, in such cases, to the 

 presence of carbonates or sulphates ; and its ready solubility, on the immediate ad- 

 dition of a drop or two of acetic acid, proves that it is not a phosphate. Farther, 



* Since this paper was read, my attention has been directed to a passage in Dr CHRISTISON'S Dis- 

 pensatory, p. 155, in which he states that all pure spring-waters contain " some vegeto-animal impreg- 

 nation," the presence of which is shewn by the discoloration of the residual salts, obtained by evaporation, 

 when farther heated. I do not know of any other chemical writer who expresses himself in equally 

 broad terms. 



VOL. XV. PART III. 5 U 



