q 6S Mr. Macartney's Observations 
spherical and minute species of medusa, but not one of the 
beroe fulgens. I observed that these luminous animals always 
retreated from the surface of the water, as soon as the moon 
rose. I found also, that exposure to the day light took away 
their property of shining, which was revived by placing them 
for some time in a dark situation. 
In that season I had two opportunities of seeing an ex- 
tended illumination of the sea, produced by the above animals. 
The first night I saw this singular phenomenon, was ex- 
tremely dark, many of the medusa scintillans, and medusa 
hemispherica had been observed at low water, but on the 
return of the tide, they had suddenly disappeared. On look- 
ing towards the sea, I was astonished to perceive a flash of 
light of about six yards broad, extend from the shore, for 
apparently the distance of a mile and a half along the surface 
of the water. The second time that I saw this sort of light 
proceed from the sea, it did not take the same form, but was 
diffused over the surface of the waves next the shore, and was 
so strong, that I could for the moment distinctly see my ser- 
vant, who stood at a little distance from me ; he also perceived 
it, and called out to me at the same instant. On both these 
occasions the flash was visible for about four or five seconds, 
and although I watched for it a considerable time, I did not 
see it repeated. 
A diffused luminous appearance of the sea, in some respects 
different from what I have seen, has been described by several 
navigators. 
Godeheu de Riville saw the sea assume the appearance 
a plain of snow on the coast of Malabar.* 
* Mem. Etrang. de 1’ Acad, des Sc. Tom. 3 . 
