WEIGHT OF FISHES. 57 



for the purpose of measurement, it may be convenient 

 to have the butt end of the fishing rod marked with a 

 scale of feet and inches. Sir H. Davy's standard was 

 a trout 1 7 inches in length, and 9 inches in breadth, 

 weighing two pounds. According to this standard, 

 then, by the mathematical rule, that similar solids are 

 to each other in the triplicate ratio of one of their 

 dimensions, a trout measuring about 24 inches will 

 weigh about five pounds ten ounces. 



