104 Book of the Black Bass. 



board flume from the river to a natural depression in the ground, 

 thereby creating an excellent fish pond of about half an acre in 

 extent, which he supplied with full-grown trout caught in the 

 river. The supply flume is, for some distance, raised about four 

 feet above the ground. About four himdred feet from the pond, 

 a small rivulet, which is an outlet for irrigating water, flows 

 under the flume, crossing it at right angles and about four feet 

 below it, and empties into the river. 



" The fall of water from the end of the flume to the surface of 

 the pond is two feet, the water in the flume flowing with a velocity 

 of three miles an hour. The pond has an outlet, which is screened 

 lo prevent the escape of the trout. Shortly after the pond was 

 established, the discovery was made that numbers of fish were 

 missing from it. Mr. Campbell instituted an investigation, which 

 resulted in discovering that the fish, dissatisfied with their new 

 quarters, had leaped through the waterfall two feet into the flume, 

 and, swimming against the strong current until they reached 

 where the stream crosses under the flume, they had leaped out of 

 the latter to the stream four feet beneath. 



" Upon discovering the method of flight adopted by his finny 

 acrobats, Mr. Campbell prevented further escape by placing a 

 screen at the mouth of the flume. Up to last accounts the dis- 

 satisfied fish had discovered no other method of getting, into their 

 favorite Sacramento. The questions immediately suggest them- 

 selves: How could the fish know that a stream flowed under the 

 flume, the sides of which were considerably above the surface of 

 the water, and if they possessed that knowledge, how were they 

 to know that they were immediately over it? Mr. Redding ex- 

 amined the ground carefully along the flume, and could not dis- 

 cover a single instance of a trout having jumped out at any other 

 place." 



Mr. Eedding subsequently communicated to the " Forest 

 and Stream " the following solution of the matter : 



" The attention of Prof. E. D. Cope, the eminent naturalist, hav- 

 ing been called to the above facts, he has given me an explanation 

 which seems entirely satisfactory. He tells me that at the base of 

 every scale of the trout, at a point where the scale is united with 



