Luminous Appearance of the Occai 



Art. II. On the Luminous Appearance of the Ocean, by Lieut. 

 Thomas R. Ingalls, U. S. Army, Corresponding Member. 



This beautiful phenomenon, which once bore the poetical title of 

 " phosphorescence of the ocean," has more recently I believe rest- 

 ed between two solutions : that it is caused by animalculae, or by 

 the ovula of fishes. The writer in a recent foreign periodical, in- 

 clines to the former opinion— -viz. that the luminous appearance of 

 the ocean is caused by animalculae. As I have been for some time 

 inclined to the opposite view of this subject, I am induced to sub- 

 humble pursuit of science. 



In the practice of sea bathing at night, in a southern latitude, I 

 had of course noticed and admired the beautiful sparkling of the 

 water when agitated or resisted— but the myriads of bodies of 

 whatsoever sort which emitted these corruscations, were alike in- 

 visible and impalpable. On one occasion however 1 struck my arm 

 against a small soft mass, which immediately emitted a flash of two 

 or three inches in diameter. But the mass eluded my attempts to 



tal contact with Jla^e^arS, 

 and I began to think I perceived a sensation of warmth whenever 

 I struck one of these bodies, though aware how liable I was to be 

 deceived by the almost irresistable association of light and heat in 

 the mind. A very large one ultimately convinced me I was not 

 deceived ; the sensation being on this occasion perfectly distinct- 

 grateful— and continuing for a minute or two after the touch. 



The masses of marine ovula, left by the tide to heat and hatch 

 on the beach, I had long before observed through the whole pro- 

 cess of vivification. First, a transparent mass of jelly—next mark- 

 ed by a white opake speck a little distant from the centre— third, 

 this spot fringed with a red border, of the colour of arterial blood ; 

 next, a kind of irregular pulsation, accompanied by the develope- 

 ment of certain white contractile fibres, and the extension of several 

 large red lines, in radial directions from the focal opake speck—the 

 appearance of a black speck, ultimately a defined head—and finally, 

 I have seen the rising tide shake out from the mass, the perfect am- 



