312 Luminousness of the Sea. 
produce this effect, and of a good many of these I made 
sketches as accurately as I could. From these observations, 
and upon comparing one of the figures I made with that of 
Macartney, I should presume that that gentleman’s opinion is 
so far correct, although he stops far too short in his general 
conclusions. Upon examining the sea water at various times, 
and in various parts of the ocean, I generally found that when 
the water was most luminous, there then was a greater abundance 
than at other times of small round globular bodies, of the 
size of grains of sand, or varying from that size to a very small 
pin’s head. The accompanying sketches (/g.81. a 6) were 
made upon examining these bodies through a microscope ; 
and though they differ a little from the figure of Macartney, 
they still approach pretty near to it in general resemblance. 
They were perfect spheres, were covered all over with innu- 
merable small round spots, much more distinctly so, than as 
figured by Macartney, and instead of a puckered opening in 
the centre as described by him, those I observed had a dark 
circular spot in the centre, with a rim round it. The circum- 
ference was rather opaque; the rest, however, with the excep- 
tion of the little round spots, was perfectly transparent. At 
times they presented the appearance in 0, instead of the cir- 
cular spot in the centre, having a dark streak running through 
it, throughout its whole breadth ; but generally their appear- 
ance was as represented in a, and frequently I observed them 
enveloped as it were in a gelatinous-looking bag, very thin 
and transparent. 
A little animal was observed by Forster, off the Cape of 
Good Hope, to be very luminous. This is represented by 
Macartney, also, from Forster’s original drawings ; and, from 
its great resemblance, he considers it as the same with his 
