Reighard. — A Plea for Record Preservation 107 



may be drawn with mathematical precision, but that 

 would require a larger number of points than we have 

 for the pike. The curve in the figure has therefore been 

 merely sketched in. It represents the relation between 

 length and weight of the 22 pike in the table. With 

 sufficient data the relation might be expressed by a curve 

 from which it would be possible to derive an algebraic 

 formula. 



The curve shows that as the pike grow longer the 

 length increases less rapidly than the weight. Thus be- 

 tween the lengths of fifteen and sixteen inches there is 

 an increase of nearly four ounces in weight, while 

 between the lengths of twelve and thirteen inches there 

 is an increase of but two ounces in weight. In other 

 words the pike increases in weight about twice as much 

 per unit of length between fifteen and sixteen inches 

 as it does between twelve and thirteen inches. 



Such a curve may very well be characteristic of the 

 lake. It may indicate whether the conditions in the lake 

 are favorable to pike, or it may have some other mean- 

 ing. To see whether the curve has any meaning I at- 

 tempted to find similar data from which to construct a 

 curve for pike from some other locality. I was unable 

 to find them and so far as I know they do not exist. In 

 Forbes and Richardson's Fishes of Illinois the average 

 length of the pike in Illinois is given as 36 inches and 

 the average weight as 80 ounces, but it is not stated 

 whether these averages are made from measurements or 

 are mere estimates. If the point for a pike of 36 inches 

 and 80 ounces is indicated on the chart it is seen, as 

 shown by the broken line, to fall well above the curve 

 for the pike of Douglas Lake. A hypothetical curve 

 sketched through this point is seen to have a different 

 form from the Douglas Lake curve. It rises more steep- 

 ly and indicates a less rapid increase of weight per unit 

 of length. In other words the pike represented by such 

 a curve would be longer for a given weight. In Douglas 

 Lake a pike of 80 ounces should be about 26 inches long, 

 while in Illinois it is said to be on the average 36 inches 



