334 



Appendices to Fifth Annual Report 



third day the points were so numerous and the liquefaction so far 

 advanced, that it was found absolutely impossible to enumerate at all. 



Third series — Made after a spell of fine weather, and when in conse- 

 quence, the river was low. 



From the right bank below the cauld (where the water, though shallow, 

 ran rapidly), there were 2500 points per c.c. 



From the left bank, at the Chain Bridge, the results were 4450 points 

 per c.c. 



In water from the right bank of the Tweed, near the Hydropathic, 

 there were 4250 per c.c. ; and in water taken from the right bank, above 

 the cauld, there were 4200 points per c.c. 



Tweed. 



Right bank, 

 below cauld 



Millstream, 

 near sluice. 



Left bank, 

 above cauld, 

 Right bank, 

 above cauld, 

 Chain Bridge, 

 left bank, 

 Near Hydro., 

 right bank, 



1st Series, 

 in fine weather. 



3000 per c.c. 



A few moist. Stag- 

 nant water. 



600 per c.c. 



One large, several 

 small moist. Run- 

 ning water. 



3024. 



Rapid liquefaction. 



2nd Series, 

 after heavy rainfall. 



Too numerous to 



count. 

 Stagnant water. 



12000. 



Rapid and extensive 



liquefaction. 

 7500. 



Medium liquefaction. 

 4120. 



Medium liquefaction. 



3rd Series, 

 after fine weather. 



2500. 



Taken from shallow 

 running water. 



4200. 



4450. 

 4250. 



On a glance at the accompanying table, several important facts are 

 observed. In the specimens from the right bank below the cauld, 

 those taken from the stagnant pools contain most bacteria and spores, 

 whilst the number is enormously increased after a heavy rainfall. It is 

 also to be observed that where the water is running, even though the 

 stream be shallow, the number is very much below the general average. 

 During fine weather it is noticeable that the number of points of growth 

 per c.c. is remarkably constant, but that after a rainfall this quality is 

 very rapidly lost. This can be accounted for in one way only, so far as 

 our observation goes. So long as there is little rainfall, and at those 

 points where no streams or rivulets join the main stream, there is practi- 

 cally no fresh supply from the surrounding drainage areas. There are 

 minor local causes of difference, such as stagnant pools, back eddies, 

 deposits of drainage sediment, &c, at certain points, in deep pools, back- 

 waters, and the like ; but when the amount of water from tributaries is 

 small, these are the only influencing causes in determining the number of 

 micro-organisms in the river water. 



After a heavy rainfall the condition of matters is altered. There is 

 now a drainage into the river from every point. Each little stream takes 

 its share of organic matter and micro-organisms from the area it drains, 

 and these streams, not mixing at once with the" general current contain a 

 greater or less number of micro-organisms. This is a point of very great 

 importance indeed, as the quality of the ground water of any area must 

 have some definite relation to that part of the river into which it drains, 

 so that very valuable information may be obtained by a careful com- 



