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, ^nd 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. 



