ANIMAL AND VEGETABLE PHOSPHOR1. l2l 



could be made, never gave any light. The herring which was 

 taken out of it the seventh night, and washed from its salt, 

 v, is found firm and sweet ; bat (he other herring was very soft and 

 putrid, much more so than that which had been kept as long in 

 fresh water. If a herring, in warm weather, be put into ten gal* 

 Ions of artificial sea-water, instead of one, the wafer, he says, 

 will still become luminous, but its light will not be so strong. 



It appeared by some of the first observations on this subject, 

 that heat extinguishes the light of putrescent substances. Mr. 

 Canton also attended to this circumstance ; and observes, that 

 though the greatest summer heat is well known to promote putre. 

 faction, yet twenty degrees more than that of the human blood 

 seems to hinder it. For putting a small piece of a lumious fish 

 into a thin glass ball, he found, that water of the heat of 118 

 degrees would extinguish its light in less than half a minute ; but 

 that, on taking it out of the water, it would begin to recover its 

 light in about ten seconds; but it was never afterwards so bright 

 as before. 



Mr. Canton made the same observation that Mr. Ant. Martin 

 had done, viz. that several kinds of river fishes could not be made 

 to give light, in the same circumstances in which any sea. fish be. 

 came luminous. He says, however, that a piece of carp made the 

 water very luminous, though the outside, or seal) part of it, did 

 not shine at all. 



For the sake of those persons who may choose to repeat his 

 experiments, he observes, that artificial sea-water may be made 

 without the use of an hydrometer, by the proportion of four 

 ounces avoirdupois of salt, to seven pints of water, wine. measure. 

 From undoubted observations, however, it appears, that in 

 many places of the ocean it is covered with luminous insects to a 

 very considerable extent. Mr. Dagelet, a French astronomer, 

 who returned from the Terra Australis, in the year 1774, brought 

 with him several kinds of worms, which shine in water when it is 

 set in motion ; and M. Rigaud, in a paper inserted (if we are not 

 mistaken) in the Journal des S9avans, for the month of March, 

 1770, affirms, that the luminous surface of the sea, from the port 

 of Brest, to the Antilles, contains an immense quantity of little, 

 round, shining polypuses, of about a quarter of a line in a dia. 

 meter. Other learned men, who acknowledge the existence of 

 these luminous animals, cannot, however, be persuaded to consider 



