436 



Transactions of the Canadian Institute. 



[Vol. VII. 



sawdust ranged half way between pine and cedar — 66 per cent, sinking 

 in eight minutes. Elm sawdust differed from pine, maple, or cedar in 

 that only about 30 per cent, sank in twenty minutes ; 75 per cent, of 

 oak sawdust sank in six minutes. So that as far as my experiments 

 went the different kinds ranged as follows : oak sank most quickly, then 

 white pine, maple, cedar, elm. But it must be remembered that the 

 particles in my experiments differed from each other in size and in the 

 moisture they contained, and consequently different results might easily 

 be obtained. The important point is that all kinds sink in a few min- 

 utes, especially in agitated water, but not, of course, in a stream with 

 anything like a rapid current. 



Extracts from Sawdust. 



The first experiments of the season were performed for the purpose 

 of determining the effects of sawdust upon fish eggs. The St. Andrew's 

 experiment had shown that adult trout were not injured by sawdust in 

 rapidly running water ; but two other points remained to be determined •" 

 (i) Whether sawdust killed fish eggs, and (2) whether it destroyed the 

 food of young, or full grown fish. 



Perch eggs were collected along the shallows of Collins Bay, just 

 west of Kingston, and brought to the laboratory on May 12th. 

 They were placed in a clean aquarium with a stream of tap water (from 

 Lake Ontario) running into and out of the vessel. On the same day a 

 bag made of bleached cheese cloth, and filled with a peck of white pine 

 sawdust was placed in an aquarium, 40^in. x I5in. x i63^in. It was 

 weighted with stones to keep it on the bottom. Water entered the 

 aquarium very slowly, so that the conditions of the experiment ap- 

 proximated somewhat to those in the pools of a sluggish stream. 



Next morning it was noted that as a result of the bag of sawdust 

 being in the aquarium all night, the water had dissolved out a suf- 

 ficient amount of material from the 

 sawdust to turn the bottom layer 

 of water a yellowish brown color. 

 This layer measured i^in. in a 

 total depth of 16)4 inches. Above 

 the yellowish brown layer, and 

 separated from it by a well-defined 

 surface, the water was as clear as 

 that of Lake Ontario. Only about 

 i^^^ of the bottom of the aquarium fig. 



