On the Phosphorescence of Marine Invertebrata. 73 
first notice their size and great number. The diameter of these 
Noctilucee, varies from about th to 4th of a millimeter; but their 
abundance more than compensates for their minuteness, each 
drop of water, as observed by Suriray and M. Verhaeghe, contain- 
In taking up some water at random from a brilliant wave, I 
filled a tube about a decimeter in height. After being left a little 
time quiet, the deposition of Noctilucze on the surface of the 
liquid was about 14 centimeters in thickness. Thus the Nocti- 
luce composed about 3th of the phosphorescent water. Again I 
took the water from the surface and filled a vessel about one- 
half. The whole height of the liquid was about 15 centimeters, 
and that of the mass of Noctilucze was about five centimeters; here 
the proportion was about $. Finally, I remember that at False 
Bay, M. de Tessan found the proportion equal to 3. From these 
numbers, it is easy to understand how the sea, rendered luminous 
by the Noctilucee, may present a uniform brillianey, irresistibly 
impressing the idea of a phosphorescent solution. hen the 
surface of the sea is tranquil, as in a well protected harbor, the 
Noctilucse, because of their small specific gravity, form a continu- 
ous bed, and the least movement is sufficient to cover that dark 
surface with a brilliant mantle. When the movement of a vessel 
at once breaks in upon this mass of Noctilucee, and also calls out 
their simultaneous phosphorescence, the myriads of bright points 
ying in the trough of the wave, present one universal hue. From 
a distance, the eye sees throughout a uniform brilliancy, and near 
by distinguishes only the most brilliant scintillations or those 
thrown out by the animals at the immediate surface of the water. 
These brilliant waves are like so many nebule resolved by the 
eye only in part. 
Parr Turrp.— Observations and Experiments on the Light of 
the Noctiluce. 
[Instead of giving a full translation of this Part of the memoir 
as has been done of the preceding, we offer here an abstract pre- 
Senting in brief the conclusions of the author,—Ebs. | 
1. Ina sea rendered phosphorescent by Noctiluce, the light 
only from the body of these animals.—T his 1 
'S proved by direct microscopic examination ;—and by the water's 
ing deprived of all light when the Noctilucz are filtered out, 
: ing luminous again when they are res to it. In 
4 tube, of the seawater, the Noctiluce if left quiet soon form a 
“ont the top of the liquid, and the light is confined entirely 
's layer of the animals. : 
.* The production of light is independent of contact ~ the 
ar—The flashes of light that are produced with the breaking 
of every wave might seem to show that the access of the animals 
Series, Vol. XVI, No. 46,—July, 1853. : 
