INTRODUCTION. 13 



streams are worthless from becoming too warm in the 

 summer. Here, also, the test should be the hottest 

 day of the dryest time. For it should be remembered 

 that one day of freshet, drought, or intense heat may 

 do as much mischief, in taking away your trout, as six 

 months of the same might do. 



The waters otherwise suitable, which are most to be 

 dreaded on account of their excessive heat, are outlets 

 of ponds or lakes, and such as are at the fish preserves 

 distant from their sources. These waters, though peren- 

 nial and of even flow, and fed by springs, may yet, 

 from too much exposure to the sun or air, be wholly 

 unfit to keep trout alive, by reason of their temperature 

 rising too high. 



This objection is not always so imperative as the 

 other two just mentioned, because there are two ways 

 of obviating it to some extent, viz. : i. By putting 

 ice in the stream. 2. By taking the water fiom near 

 its source, through a pipe under ground. The first 

 remedy often involves so much risk, as well as 

 expense and necessity of constant vigilance in hot 

 weather, that it had better not be contemplated, 

 except in cases of great counterbalancing advantages. 

 The latter remedy, however, when it will pay, is usually 

 practicable, and will do if it can be made safe. But, 

 at all events, make sure either that the water will keep 

 cool of itself, or that you can and will keep it cool 

 enough by one method or another. 



Under this head it may be suggested that the quan- 

 tity and force of current and vigor * of the water have 



* I cannot exactly define the word " vigor " in its present ap- 



