428 Elimination of Algcz in Lochs and Ponds. [Sess. 



fact, but the reason for it has not as yet been ascertained. 

 The temperature and hardness of the water are factors to be 

 taken into account when determining the strength of the 

 solution. We have also seen that Algse vary in their powers 

 of resistance, and the same conditions have been found to 

 exist amongst fishes, certain kinds being rapidly killed off by 

 a solution which would have little or no effect on those of a 

 less delicate nature. 



So far as known to me. The Haining loch is the only case 

 in Scotland, up to the present time, of a sheet of water having 

 been freed from obnoxious Algae by means of sulphate of 

 copper. In England, however, there have been several 

 instances of recent years. For the details regarding a very 

 remarkable example I am indebted to Professor G. S. West of 

 Birmingham University. The locality was Barnt Green, 

 about eight miles south of Birmingham, where a large 

 reservoir had become filled with two of the Blue-green Algye 

 which have elsewhere caused so much trouble, namely, 

 Anahcena and Oscillatoria. The circumstances will be best 

 described in Professor West's own words. He writes to me 

 thus : " The Barnt Green Eeservoir, a lake used as the head- 

 quarters of both a yacht-club and a fishing-club, about one 

 mile and a half in length by three-fourths of a mile broad, 

 was treated with copper sulphate at my suggestion in 1909. 

 The volume of the water was estimated as nearly as possible, 

 and the copper sulphate used in the strength of one part in 

 two millions. It should not exceed this proportion. This 

 lake required about 1500 cwts. of CUSO4 to give the strength 

 of one part in two millions of water ; and to diffuse it 

 thoroughly, it was placed in coarse canvas sacks and towed 

 after the yachts when racing. The offensive * water- bloom ' 

 was quite cleared away after about a fortnight, and the fishing 

 has been better than ever, since the treatment. So far as I 

 can ascertain, no fish were killed. I daresay one part in 

 three millions of water would suffice." Professor West adds 

 that he has tried this method upon several smaller sheets of 

 water, with complete success, and that he has also recom- 

 mended it to a number of people for clearing ornamental 

 lakes. 



The following account of what is being done by the author- 



