Experiments on the Noctiluca miliaris. 407 



Taking, as a good example, the night of the 9th of August 

 last, which was remarkably bright and cloudless, and at the 

 same time serene and mild, the phosphorescence of the waters 

 of our bay, which had been visible in a less degree for many 

 preceding nights, assumed about midnight a very brilliant 

 and beautiful appearance. Seen from a distance, the aspect 

 presented at this time by the whole surface of the water was 

 that of a diffused silvery light, which caused the dark head- 

 land of Brean Down, on the opposite side of the bay, to ap- 

 pear as if laved by liquid silver. On approaching nearer the 

 water's edge, so as to observe more distinctly the waves as 

 they broke gently and with even regularity upon the strand, 

 the effect can only be compared to masses of liquid tire rolling 

 and pouring in, and diffusing itself along the shore. On the 

 north-west point of the bay is a projecting rock called Knight- 

 stone, joined by a raised causeway to the main land, and 

 forming at high water a sort of short pier, alongside of which 

 a few small vessels and boats usually lie at anchor. The 

 shelter against the current, together with the shade afforded 

 by the rock and walls of the pier, combined to prove highly 

 favourable to an observation of the effect in comparatively 

 still water, and under increased darkness. On looking down 

 then at this point, between the sides of the vessels and the 

 rock, a constant scintillation was to be observed on the sur- 

 face of the water, very similar to a shower of fire or sparks, 

 the luminous points, some larger, others less in size, perpetu- 

 ally dancing up as it were to the surface, and soon again dis- 

 appearing to be replaced by others. The larger points, some 

 of which were as large as a pea, were produced, I conceive, 

 from several of the little animals having floated into close ap- 

 proximation or contact, whilst the smaller ones, I imagine, 

 proceeded from detached individuals. 



On striking the surface of the water lightly with an oar, 

 not only the spot immediately touched, but also all the water 

 dashed up, appeared, whilst raised in the air, and again on 

 falling into the surrounding water, to bear an exact resem- 

 blance to liquid fire, affording a spectacle of the most brilliant 

 description. Several bottles were then filled with the water 

 from this spot where it appeared brightest. I likewise pro- 

 cured a bucketful of the same kind, and the whole was 

 brought home for the purposes of observation and experiment. 

 As tending to convey some further idea of the luminous 

 power of the water in its natural condition, it may be men- 

 tioned that on rendering my room perfectly dark and agitating 

 the water in one of these bottles, it perfectly illuminated any 

 object in its vicinity, so as to enable me to distinguish various 



