some Marine Invertebrata. 181 



merous, always isolated, and not giving at all the idea of a liquid 

 in itself luminous ; 2nd, a general glow more or less uniform, 

 the phosphorescent substance seeming to be dissolved in the 

 water itself. 



In both cases phosphorescence is equally a result from living 

 animals directly emitting the light, but the species which pro ■ 

 duce the phsenomenon are different. 



A. I have often observed the first mode of phosphorescence on 

 the western coasts of France, at points peculiarly exposed to the 

 action of currents and waves. At Chausey, especially in the small 

 channel called " le Sund de Chausey," I have seen very numerous 

 and brilliant sparks brought out by each stroke of the oar. The 

 track of the vessel seemed for a moment as if strewn with dia- 

 monds, but these sparks, always very brilliant, and appearing 

 at the same instant^ never communicated a general glow to the 

 water. They remained completely isolated, and were distinct 

 from the dark surface of the sea. At Brehat, St. Malo, and 

 St. Vaast, I observed similar facts. The fishermen whom I 

 questioned, all assured me that in these regions, the sea never 

 presented a different appearance ; the young men who had never 

 left their native coasts, did not seem to understand my in- 

 quiries relative to a more general or diffused phosphorescence. 

 M. Beautemps-Beaupre mentions his observing phosphorescence 

 of this kind during one of the numerous excursions in which he 

 was engaged, while making his magnificent Atlas of the coasts of 

 France ; but he cannot recall the exact locality. It was in the 

 neighbourhood of St. Brieuc, and it may be that this single ob- 

 servation was made in some well-sheltered harbour, like the port 

 of Paimpol. 



If the sea itself rarely presents any remarkable phospho- 

 rescence in the localities of which I am about to speak, it is not 

 so with the marine plants which are left by the tide. In some 

 circumstances I have seen masses of the Fucus kindle up when 

 seized a little rudely ; but even then the light was in isolated 

 points, which the eye easily distinguished from one another. In 

 no case did the stalks or the leaves present the uniform tint of 

 a metal at a white heat, and the water which ran out freely was 

 never luminous. Moreover, the part of the beach which the sea 

 had just left dry remained perfectly dark. At most, only a few 

 sparks might be seen over a space of some extent. 



Water drawn from the sea in the circumstances of which I 

 speak, and when the scintillations were most numerous and most 

 brilliant, often became suddenly obscure, or presented only some 

 few luminous points, when the vase containing it was violently 

 shaken, and these ordinarily disappeared instantly. This same 

 water, poured out from some height, presented nothing peculiar. 



