yOL. LIX.] PHILOSOPHICAL TRANSACTIONS. 681 



made, never gave any light. The herring, which was taken out of it the 7tli 

 night, and washed from its salt, was found firm and sweet ; but the other her- 

 ring was very soft and putrid ; much more so than that which had been kept as 

 long in the fresh water of the last experiment. If a herring, in warm weather, 

 be put into 10 gallons of artificial sea-water, instead of one, the water will still 

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



The artificial sea-water may be made without the use of an hydrometer, by 

 the proportion of 4 oz. avoirdupois of salt, to 7 pints of water, wine-measure. 



From the 2d and 3d experiments it is evident, that the quantity of salt con- 

 tained in sea-water hastens putrefaction ; as the fish that had been kept in water 

 of that degree of saltness was found to be much more putrid than that which 

 had been kept the same time in fresh water. This unexpected property of sea- 

 salt was discovered by Sir John Pringle, in the year 1750, and published in the 

 46th vol. of the Phil. Trans., with many curious and useful experiments on 

 substances resisting putrefaction ; but the greatest quantity of salt there men- 

 tioned, is less than what is found in sea-water : it is probable therefore, that if 

 the sea were less salt, it would be more luminous. And here it may be worth 

 remarking, that though the greatest summer heat is well known to promote 

 putrefaction, yet 20 degrees more than that of the human blood seem to hinder 

 it: for, putting a very small piece of a luminous fish into a thin glass bail, the 

 water of the heat of 1 18 degrees destroyed its luminousness in less than half a 

 minute ; which, on taking it out of the water, it would begin to recover in about 

 1 seconds, but was never after so bright as before. 



Mr. C. then adds to these experiments the two most circumstantial accounts he 

 could find of the sea's luminous appearance. Mr. Boyle, in the 3d volume and 

 Qlst page, of Birch's edition of his works, says, "When I remember how many 

 questions I have asked navigators about the luminousness of the sea; and how 

 in some places the sea is wont to shine in the night as far as the eye can reach ; 

 at other times and places, only when the waves dash against the vessel, or the oars 

 strike and cleave the water ; how some seas shine often, and others have not 

 been observed to shine ; how in some places the sea has been taken notice of, to 

 shine when such and such winds blow, whereas in other seas the observation 

 holds not : and in the same tract of sea, within a narrow compass, one part of 

 the water will be luminous, whilst the other shines not at all : when, I say, I 

 remember how many of these odd phenomena, belonging to those great masses 

 of liquor, I have been told of by very credible eye-witnesses, I am tempted to 

 suspect that some cosmical law or custom of the terrestrial globe, or, at least, 



• Several river-fish, as the bleak, the dace, the carp, the tench, and the eel, were kept in arti- 

 ficial sea-water to putrefy, without producing any light that could be perceived, but a piece of a carp 

 made the water very luminous, though the outside, or scaly part of it, did not shine at all. — Orig, 



VOL. XII. 4 S 



