A DESCENT INTO PERPETUAL NIGHT 209 



a slight fanning with a dorsal fin. Keeping equal distances 

 apart, and maintaining their upright pose, they swam 

 slowly into the uttermost dark. The amazing thing about 

 them was their unexpected pattern and color. The jaws 

 and head were brilliant scarlet, which, back of the gills, 

 changed abruptly into a light but strong blue and this 

 merged insensibly into clear yellow on the posterior body 

 and tail. Unless in the light of some other fish, or in my 

 electric path, their colors could never have been visible, 

 and were assuredly useless by-products. 



I alternated v/ith Mr. Barton's camera at the window 

 and there were hardly any seconds without lights or def- 

 inite organisms coming into view. In one period of this 

 duration, chosen at random, I counted 46 Kghts, ten of 

 which were of unusual size, most of them pale yellow, but 

 a few bluish. The sight I enjoyed most was a momentary 

 glimpse of what I am certain was the same, or another, 

 Pallid Sailfin. In all this vast extent in three dimensions, 

 of black water, the chance of confirming at a wholly dif- 

 ferent depth a new observation made my satisfaction com- 

 plete. 



The change in the electric beam itself from 1000 feet 

 downward was interesting. At the upper layers it was weak 

 but decidedly yellow, with a turquoise cap at the farther 

 end of the oblique luminous shaft. As we descended, the 

 yellow changed to a luminous gray, and the turquoise 

 crept down, until, at this extreme depth, it reached to the 

 very window. Along each side of the sharply marked beam 



