420 PROFESSOR CONNELL ON THE PRESENCE OF ORGANIC MATTER 



lihood allied to the apocrenic acid. It did not seem that the whole of this matter 

 was procured by the process followed ; for when the potash salt was farther diluted 

 than above stated, but to an extent much short of the original bulk of the water, 

 it ceased to be acted on by the lead salt. 



My attempts to obtain larger quantities of this substance, by precipitating 

 successive portions of the water in the same vessel, and allowing the several 

 precipitates to accumulate together, were unsuccessful, when the process was 

 continued for a week or two, the precipitate, by standing, apparently suffering 

 some degree of decomposition, or otherwise escaping the subsequent agency of 

 the sulphuretted hydrogen ; for in this way I ultimately obtained considerably 

 less matter than by a single operation concluded without delay, as above 

 described. It was found by BEKZELIUS that the salts of crenic acid are extremely 

 liable to decomposition ; and to the same cause was probably due the partial loss 

 in the single operation. 



I could have wished to try the decomposition of the precipitate from a purer 

 water, and therefore less liable to give an intermixture of inorganic salts ; but at 

 the time, I had not access to a sufficient quantity of any of those purer spring 

 waters which I examined on a smaller scale. 



Having thus, as I trust, shewn that some degree of confidence may be placed 

 in the reactions to which I have alluded as indicative of the pi'esence of organic 

 matter in water, I shall proceed to mention those instances in which I have 

 convinced myself, by such indications, of the presence of this matter. 



Besides the town water of St Andrews, I have found it in the town waters 

 of Edinburgh and Glasgow. Edinburgh, as is well known to its inhabitants, is 

 chiefly supplied from a celebrated spring in the vicinity of the Pentland Hills. 

 The water, as it comes into the town, contains only from lygggth to j^ooth of its 

 weight of inorganic salts, which are chiefly carbonate and sulphate of lime, and 

 a little sulphate of magnesia. In this water, by the reactions already detailed, I 

 fully satisfied myself of the presence of this organic matter. Its quantity was 

 greater during dry weather in summer than after rains in winter, a result quite 

 to be anticipated. The town of Glasgow is supplied from the river Clyde ; and 

 at the time I examined its water, which was in winter, the river was in high 

 flood from heavy rains, and so muddy, that I could not employ the water taken 

 directly from the channel ; but in the water brought from the river into the 

 houses, which has been cleared by subsidence and filtration through sand and 

 gravel, I found this organic matter, although to a less extent than in the St An- 

 drew's and Edinburgh waters, a circumstance which was probably due more or 

 less to the large quantity of rain-water present at the time. I have farther found 

 this matter abundantly in all the running streams and wells which I have ex- 

 amined around St Andrew's ; and likewise in such well-waters about Edinburgh 

 as have come under my notice. 



