402 Dr. J. H. Pring's Observations and 



The attrition of the saline particles against each other, or 

 some unknown combination amongst them, has also been re- 

 garded as a source of this marine light, whilst it has further 

 been attributed to the presence of phosphoric matter extricated 

 from decomposing fish, &c.; and lastly, it has been very gene- 

 rally referred, especially in recent times, to a power of phos- 

 phorescence possessed by numerous living marine animals, 

 similar, for the most part, in its character to that exhibited by 

 the glow-worm and fire-fly on land. 



It is almost needless to observe, that, of the foregoing theories, 

 the last may now be said to be universally admitted as correct; 

 yet it is surprising that even with some of those who have in- 

 vestigated the subject in a scientific point of view, no very 

 distinct ideas seem to be entertained as to the precise nature, 

 even in the instance of our own seas, of the animalcular source 

 to which the light is thus in general terms ascribed; whilst 

 the notions prevalent amongst sailors and others serve only to 

 exhibit how little has as yet been done towards removing the 

 popular ignorance in which the subject still remains enveloped. 



Amongst the scientific world again, we find that investiga- 

 tion has chiefly been directed to those instances of vital phos- 

 phorescence which are presented by that division of the animal 

 kingdom which is confined to the land; yet this division sinks 

 into comparative insignificance when contrasted with the great 

 variety and infinite multitudes of phosphorescent animals which 

 inhabit the ocean. 



With a view, however, to rendering the present notice more 

 complete, we shall glance rapidly at some of the more promi- 

 nent instances of phosphorescence as displayed by land ani- 

 mals, and then notice briefly some of the more important in- 

 stances afforded by the tribes inhabiting the sea ; dwelling 

 more particularly, as regards the latter, on the example which 

 forms the chief subject of the present communication, the 

 Noctiluca miliaris, to which the phosphorescence occasionally 

 witnessed in the British seas is mainly attributable. 



If we except the instance of the Great American Bittern 

 amongst birds, which has been stated to possess the power of 

 " emitting a light from its breast equal to that of a common 

 torch, which illuminates the water so as to enable it to discover 

 its prey*," we are not aware that the property of phosphores- 

 cence has been attributed to any land animals until we descend 

 so low in the scale as the class of Insects ; a division, however, 

 in which this jxjwer is very numerously and conspicuously dis- 

 played, the family of the Lampyridae, or glow-worms alone 

 containing about 200 species known to be luminous, whilst 

 * See Loudon's Magazine of Natural History, vol. ii. p. 200. 



