The Puzzle of the Tlk-Fish. 165 



that there had been a progressive movement of tlie warm body 

 of water toward the shore, and saw plainly that if the same rate 

 were to hold good this year the whole of the continental edge of 

 the area in question would in all probability be covered by the 

 warm water. The idea then suggested itself that if such were the 

 case the conditions for the reappearance of the tile-fish would 

 be established, if environment meant anything in the case. The 

 fish had been previously in a depth of water varying from 70 

 to 120 fathoms, and its feeding ground, being on the bottom, 

 would occur just at the edge of the platform. It was probably, 

 moreover, a tropical deep-sea fish, and the temperature at which 

 it was caught (50° to 58°) could only be established on the 

 New England coast by just such an invasion of the continental 

 edge as has been described. It is only necessary to conceive 

 that the whole of the continental edge from Florida to Nantucket 

 is thus overflowed by this warm band of water to see how the 

 regular feeding ground of a tropical fish could be extended so 

 that the fish could follow it tliroughout the whole of this largely 

 increased area. 



While in the midst of this interesting theoretic work I was 

 aroused by a letter from Washington, from Colonel McDonald, 

 stating that owing to an economical turn, Congress had largely 

 reduced the appropriation for the Commission, so that we should 

 have to give up a great portion of the scientific Avork. I went 

 to Washington with my facts, and they interested the Commis- 

 sioner to such an extent that he agreed to give me the chance 

 to test the theory, and further expressed a wish to take part in 

 the work himself. 



We first went out south of Marthas Vineyard, found that 

 the temperature was right, set the trawl lines and caught the 

 fish. During the next two months I spent considerable time in 

 tracing up the area over which the temperature of 50° and over 

 was to be found on the continental edge, fishing at the same 

 time with the trawls to see if the fish were there. We found 

 them all the way to the Delaware capes, and were satisfied that 

 though they were not numerous they had taken advantage of 

 changed conditions over the area to occupy an enlarged feeding 

 ground. 



The exjjlanation of the disappearance of the fish in 1882, as 

 suggested by Colonel McDonald, seems now to cover the ground 



