184 WATER-LILIES 



vitriol) to be used depends upon a number 

 of factors, such as the particular kind of or- 

 ganisiB to be destroyed, temperature, tempo- 

 rary hardness of the water, etc., the reader 

 had best consult Bulletin No. 76, Bureau of 

 Plant Industry, U. S. Department of Agricul- 

 ture, in which the method is treated in detail. 

 In puddled ponds the crawfish may be a 

 source of great annoyance, not only because 

 they cut off the young leaves and even the 

 buds, but also because they bore deep holes 

 through the bottom of the pond, practically 

 turning it into a sieve. Here an ounce of 

 prevention is worth a pound of cure. At the 

 last minute, that is to say, six or seven days 

 before planting, nearly empty the pond. 

 Thousands of crawfish, both young and old 

 will be seen. It is sufficient to sprinkle 

 tobacco dust plentifully. This is effectual in 

 killing all crawfish, and all other animal life, 

 which later may advantageously be replaced 

 by a generous supply of goldfish. In a couple 

 of days flush the pond and empty it once more 

 to clean it out and to repuddle where neces- 



