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presents the aspect of red-hot cinders ; tins appearance, under 
the most favourable circumstances, extending at times to a 
distance of some inches from the impression left by the foot. 
Such are the chief phenomena that accompany general or 
diffused phosphorescence ; of a totally distinct character, how- 
ever, are those which I ascribe to partial phosphorescence. In 
this there is nothing’ to remind one of the uniform tint that con- 
veys an idea of the transmutation of the very liquid itself into 
the fiery element. The light is emitted only in isolated points, 
absolute scintillations, which usually appear and disappear with 
great rapidity. However numerous these sparks may be, they 
never by any chance coalesce ; they stand out clearly from the 
dark background formed by the surface of the water, and their 
brilliancy is considerably heightened by the striking contrast. 
The spectacle which they produce is often a grand one. In the 
little channel known as the “ Sund de Chausez,” I have seen, 
on a dark night, each stroke of the oar kindle, as it were, 
myriads of stars, and the wake of the craft appeared in a 
manner besprinkled with diamonds. 
At Brehat, St. Malo, St. Yaust, and at Biarritz, I have col- 
lected similar data, and believe that I may unhesitatingly say 
that in those unsheltered roadsteads on the coast, which are 
entirely exposed to the free action of the waves, this, if not the 
only one, is at least the most frequent mode of phosphorescence. 
It is with this kind of phosphorescence that I associate that 
of marine plants, so far as it has presented itself to my obser- 
vation under certain circumstances ; more especially as I wit- 
nessed it in the narrow channels which separate the rocks and 
granitic islets of our small archipelagos in Brittany. 
There I have seen entire masses of fucus kindle, as it were, 
when roughly shaken ; but even then the luminosity presented 
itself in isolated points, which the eye could easily distinguish. 
Under no circumstances did either stems or leaves exhibit the 
uniform glow of a metal raised to a white heat, and the water 
which drained from the plants was perfectly dark. 
2. Causes of the Phosphorescence. 
It may readily be conceived that a phenomenon so remark- 
able as that which is occupying our attention should early 
have attracted the notice both of the savant as well as of the 
superficial observer, and owing to that tendency of the human 
mind which prompts it to search after causes, before even it is 
conversant with the nature of effects, explanations could not 
fail to abound. This is precisely what has happened. It is 
almost needless to say that many of these solutions, hazarded 
at the first blush, and based upon appearances only, would 
