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In it, were perfe(!!i:ly dark during the whole time. 
The thermometer was generally above 6o. - 
Experiment III. 
Into a gallon of frelh water I put common or 
fea-falt, till I found by an hydrometer it was of the 
fame fpecific gravity with the fea-water. In another 
gallon of frefh water I diffolved two pounds of fait: 
and into each of thefe waters I put a fmall frefh 
herring. The next evening the whole furface of the 
artificial fea-water was luminous without being ftirred, 
but gave much more light when it was difturbed. It 
appeared exadlly like the real fea-water in the pre- 
ceding experiment, and its light lafled about the 
fame time, and went off in the lame manner^. The 
other water, which was almofl as fait as it could be 
made, never gave any light. The herring, which 
was taken out of it the feventh night, and wafhed 
from its lalt, was found firm and fweet j but the 
other herring was very foft and putrid j much more 
fo than that which had been kept as long in the frefli 
water of the laft experiment. If a herring, in warm 
weather, be put into ten gallons of artificial fea-water 
inftead of one, the water will Hill become luminous, 
but its light will not be fo ftrong. 
N. B. The artificial fea-water may be made witl>- 
out the ufe of an hydrometer, by the proportion of 
* Several river- filh, as the bleak, the dace, the carp, the 
tench, and the eel, were kept in artificial fea-water to putrefy, 
without producing any light that I could perceive : but a piece 
of a carp made the water very luminous, though the outfidc, or 
fcaly part of it, did not ftiine at all. 
k 
four 
