of the Fishery Board for Scotland. 



19 



With regard to the effect which the high temperature of those 

 discharges has upon the river I was able to make only very imperfect 

 observation, by taking an occasional reading with a thermometer 

 dipped from the river bank. Daily readings were, however, taken 

 for me during May, June, and July, in the river at Dumbarton and 

 in the Clyde outside the river mouth. The means for those months 

 are : — 



1905. Leven. Clyde. 



May, ... 51° 53° 

 June, ... 59° 59° 

 July, ... 59° 62° 



On the two days during which my inspection of the Leven 

 lasted, the readings at the above places were : — 



Leven. Clyde. 

 29th June, . . . 64° 65° 

 30th „ . . . 63° 65° 



My own observations, taken as described in proximity to the 

 works, showed a temperature of from 68° to 69°, and below the 

 last of the works (Dalquhurn), but not more than 100 yards below 

 the outfalls, I obtained a reading of 72°. The weather was 

 extremely hot at the time, and this, no doubt, must be taken into 

 consideration ; but the inference seems to me to be that the 

 temperature of the water in the Leven is materially affected by the 

 discharges from the works, although, no doubt, markedly high 

 temperatures such as above are very local. Some accurate obser- 

 vations as to the proportion of oxygen in the water at different 

 parts of the river would be of value, as well as analysis for some of 

 the more toxic pollutions. I am strongly of opinion, however, 

 from what I have seen, that while some polluters of the river make 

 reasonable and fair attempts to reduce the evil effects of their bye- 

 products, others do not do so, and that if an equitable share in 

 works of purification were borne by the various companies involved 

 a material improvement would be seen in the condition of the river. 

 With the great variety of substances which are introduced into the 

 effluents it is more than likely that with a more complete system 

 of mixing, and the possibility of greater time being given to the 

 process of settling, much greater sedementation would result. It 

 might, I think, very fairly be considered, for instance, whether or 

 not some system could be adopted by which the waste liquors of 

 certain works could be combined and treated collectively on each 

 side of the river. And I consider that the particular works at 

 which little or no treatment is at present existant might be 

 reasonably required to purify their effluents. And in connection 

 with a more systematic purification it would, I consider, be valu- 

 able that by analysis of the effluents and by agreement between 

 the parties concerned a standard of purity should at the same time 

 be established. 



Deveron. 



In February 1898 the cruive dyke, formerly situated about two 

 miles from the mouth of this river, was removed, and a marked 



