Miscellaneous. 325 



catfish, perch and sunfish. The owner wished to clear 

 his pond of all these, render it lifeless and then restock 

 it with trout, for the waters were cool enough in sum- 

 mer! In April, 1899, 200 holes, fifty feet apart, were 

 cut through the ice and dynamite in half-pound sticks, 

 twelve to each hole, were lowered to within four feet of 

 the bottom. Each lot of sticks was connected by wire 

 to electric batteries, so arranged that there would be 

 three explosions about half a second apart. The but- 

 ton was pressed and columns of ice and water, from 10 

 to 1 5 feet in diameter, went up a hundred feet or more. 

 The concussion shook the earth about the shores and 

 the lake was barren of fish, insect larvae and crusta- 

 ceans. The larvae will all come back, but the owner 

 will have to see to the vegetation and the crustaceans. 

 If he gets his plants from neighboring lakes of the 

 same character he will get all these forms entangled in 

 it without paying further attention to them. 



CHAPTER XLVIII. 



TO MEASURE A FLOW OF WATER. 



Often a correspondent seeks advice about trout 

 ponds and to a question regarding the highest tempera- 

 tures and the amount of water flowing in the driest 

 time, replies that he is ignorant on these points. The 

 temperatures he can get with more or less accuracy, 

 dependent on the unreliability of cheap and untested 

 thermometers ; but the amount of flow is usually a 



