SEA, 
tudes the proportisn was still greater; he 
found it to contain the following proportions : 
In the Mediterranean the proportion is said 
to be still greater; but the Euxine and 
Caspian seas are found to be less salt 
than the ocean. This is also the case with 
the Baltic. If the saline matters of the 
waters of the ocean did not consist of dif- 
ferent kinds, the proportion of salts which 
it contains might be ascertained by the spe- 
cific gravity. The experiments of Mr, 
Wilcke show that the proportion of saline 
matter in the Baltic is less than that of the 
ocean : and that it is salter during the pre- 
valence of a westerly Wind, by which the 
water is driven from the ocean, than during 
an easterly wind. The proportions of the 
different salts in an analysis, by Bergman, 
;^re the following : 
Muriate of soda 30.911 
Muriate of magnesia 6.222 
Sulphate of linie 1.000 
38.133 
In 1,000 parts of water taken up near 
Dieppe, Lavoisier found the following salts : 
Muriate of soda 1.375 
Muriate of lime and magnesia ... 256 
Muriate of magnesia 156 
Lime 87 
Sulphate of soda aud magnesia .. 84 
1958 
The luminousness of the sea is a pheno- 
menon that has been noticed hy many nau- 
tical and philosophical writers. Mr. Boyle 
ascribes it to some cosmical law or custom 
pf the terrestrial globe, or at least of the 
planetary vortex. 
The Abbe Nollet was long of opinion, 
that the light of the sea proceeded from 
electricity ; and others have had recourse 
to the same principle, and shown that the 
luminous points in the surface of the sea are 
produced merely by friction. 
There are, however, two other hypothe- 
*es, which have more generally divided be- 
tween them the solution of this phenome- 
non ; the one of these ascribes it to the 
shining of luminous insects or animalcu- 
les, and the other to the tight proceeding 
from the putrefaction of animal substances. 
The Abbe Nollet, who at first considered 
this luminousness as an electrical pheno- 
menon, having had an opportunity of ob- 
serving the circumstances of it, when he 
was at Venice in 1749, relinquished his for- 
mer opinion, and concluded that it was 
occasioned either by the luminous aspect, 
or by some liquor or effluvia of an insect 
which he particularly describes, though he 
does not altogether exclude other causes, 
and especially the spawn or fry of fish. A 
similar conjecture is proposed by a corres- 
pondent of Dr. Franklin, in a letter read at 
the Royal Society in 1756 ; the writer of 
which apprehends, that this appearance 
may be caused by a great number of little 
animals, floating on the surface of the sea. 
And Mr. Forster, in his account of a voy- 
age round the world with Captain Cook, 
describes this phenomenon as a kind of 
blaze of the sea; and having attentively 
examined some of the shining water, ex- 
presses his conviction that the appearance 
was occasioned by innumerable minute 
animals of a round shape, moving through 
the water in all directions, which show se- 
parately as so many luminous sparks when 
taken up on the hand : he imagines that 
these small gelatinous luminous specks may 
be the young fry of certain species of some 
medusae or blubber. And M, Dagelat and 
M. Rigaud observed several times, and in 
different parts of the ocean, such luminous 
appearances by vast masses of different 
animalcules ; and a few days after, the sea 
was covered, near the coasts, witli whole 
banks of small fish in innumerable multi- 
tudes, which they supposed had proceeded 
from the shining animalcules. 
But M. le Roi, after giving much atten- 
tention to this phenomenon, concludes, that 
it is not occasioned by any shining insects, 
especially as, after carefully examining 
with a microscope some of the luminous 
points, he found them to have no appear- 
ance of an animal ; and he also found 
that the mixture of a little spirits of wine 
with water Just drawn from the sea, would 
give the appearance of a great number of 
little sparks, which would continue visible 
longer than those in the ocean : the same 
effect was produced by all the acids, and 
various other liqours. M. le Roi is far from 
asserting that there are no luminous insects 
in the sea ; for he allows that several gen- 
tlemen have found them ; but he is satisfied 
that the sea is luminous chiefly on some 
other account, though he does not so much 
as offer a conjecture with respect to the 
true cause, 
Other authors, equally dissatisfied with 
the hypothesis of luminous insects, for ex- 
plaining the phenomenon which is the sub- 
t 
! 
I 
