k 



427 



It occurred to the author that the true cause of the reaction was 

 to be found in the presence of organic matter in the water, derived 

 fi'om the decomposition of vegetable matter in the strata or soil 

 through which it had passed. To ascertain whether this view was 

 correct, the precipitate by acetate of lead from several quarts of the 

 town water of St Andi-ews was decomposed by sulphuretted hydro- 

 gen. After filtration, a liquid was obtained, which, besides sul- 

 phuric acid derived from precipitated sulphate of lead, was found to 

 contain some organic matter apparently of an azotiscd nature ; but 

 its amount was too small to characterise its properties with accuracy. 

 The salt obtained by saturating the liquid with potash, yielded by 

 distillation cmpyreumatic vapour, and loft a black coaly mass be- 

 hind. The liquid itself, when neutralized and sufficiently diluted, 

 had still a marked action on lead salts ; and it or its potash salt 

 produced more or less precipitate after the interval of a day or two, 

 in acetate of copper and neutralized persulphate of iron. 



The author has found this matter in the town waters of Edin- 

 burgh and Glasgow, but to a less extent than in that of St Andrews. 

 The Glasgow water shewed the least of the three. He has also 

 found it more or less in every instance he has hitherto tried of trans- 

 parent and colourless well, spring, or river water. In rain water it 

 does not exist, and probably could not be found in springs above the 

 limits of vegetation, or in snow or glacier water. It would seem 

 that it ought to perform functions of some importance in the econo- 

 my of nature, as contributing in a cci-tain degree to the nourishment 

 of plants and even of animals. 



2. Biographical Sketch of the late Sir Charles Bell. By Sir 



John MacNeill. 



This paper is, from its nature, incapable of being here given in 

 an abridged form. 



3. Notice regarding the Bebeeru Tree of British Guiana. By 



Dr A. Douglas Maclagan. 



The plant bearing the above Indian name, and also called Sipcori 

 by the Dutch colonists, furnishes the hard and heavy timbei- known 

 by the name of Greenheart. The object of the present paper was to 

 state the result of experiments made by the author on the bark and 

 seeds of the tree, which had been found by Mr llodie, R. N., to con- 

 tain a vegetable alkaU possessed of the power of checking intermit- 



