8 Mr. Waldies investigations. [No. 1, 



the season has advanced, the fetid smell has materially diminished. 

 This is indeed to have been expected : the soil has been washed 

 comparatively clean, and there is less of such matter to wash away. 



The only possible way in which my results as to the small quantity 

 of organic matter in the water of the hot season (supposing there is no 

 great error in the analysis) can be reconciled with the results of those 

 analyses that give it as equal to 8 or 10 grains per gallon, would be to 

 suppose that the water at that season contains a large quantity of 

 organic matter having no very offensive smell, but capable of very rapid 

 decomposition, so that about -|th to T 9 th of it would be lost during the 

 first two weeks. Without denying the possibility of this, I can only 

 say that I know of nothing that makes it probable that such is the 

 case, while I have already given reasons for believing that no such 

 state of matters exists. Further observation and experiment can 

 alone decide the question beyond doubt ; while I may remark that 

 if such be the case, it will be a fact well worth noticing and establish- 

 ing. 



It may also be observed, that as in the case of supplying towns the 

 water must always be stored for a time in tanks or reservoirs, it is a 

 point of some importance to note the changes which it undergoes by 

 keeping in these circumstances. I have made some observations in the 

 course of these enquiries suggestive of further investigations on this 

 subject, and which may also have a bearing on the purification and 

 preservation of such waters, a subject which has lately been occupying 

 much attention in England. It is obviously a possible thing that one 

 water may be putrefying but its putrescibility nearly exhausted, while 

 another may be highly putrescible, and yet its actual putrefaction may 

 be only about to commence. As regards the preservation of waters 

 too, it is one thing to keep them in stoppered bottles, and another 

 thing to keep them in tanks. It seems to me questionable if they 

 improve in tanks as they do in glass bottles. It is by following out 

 such inquiries that advance in knowledge of such subjects is attained, 

 and in the present case the activity of chemical changes produced by 

 the high temperature and the regularity of the seasons are in no 

 small degree favourable for carrying them to a successful result. 



