120 ANIMAL AND VEGETABLE PHOSPHORI. 



the fish which waseren with the surface of the water was luminous, 

 but the water itself was dark. He drew the end of the stick 

 through it, from one side of the pan to the other, and the water ap. 

 peared luminous behind the stick all the way, bat gave light only 

 where it was disturbed. When all the water was stirred, the 

 whole became luminous, and appeared like milk, giving a consi- 

 derable degree of light to the side of the pan ; and it continued to 

 do so for some time after it was at rest. The water was most lu. 

 minons when the fish had been in it about twenty-eight hours ; but 

 would not give any light by being stirred, after it had been in it 

 three days. 



He then put a gallon of fresh water into one pan, and an equal 

 quantity of sea-water into another, and into each pan he j.ue a 

 fresh herring of about three ounces. The next right the whole 

 surface of the sea-water was luminous, without b ing stirred : but 

 it was much more so when it was put into motion ; and the upper 

 part of the herring, which was considerably below the surface of 

 the water, was also very bright; while at the same time the fresh 

 water, and the fish that was in it, were quite dark. There were 

 several very bright luminous spots on different parts of the 

 surface of the sea-water ; and the whole, when viewed by the 

 light of a candle, seemed covered with a greasy scum. The third 

 night, the light of the sea- water, while at rest, was very little, if 

 at all, less than before ; but when stirred its light was so great as 

 to discover the time by a watch, and the fish in it appeared as a 

 dark substance. After this its light was evidently decreasing, but 

 w?is not quite gone before the 7th night. The fresh water and the 

 fish in it were perfectly dark during the whole time. The ther. 

 mometer was generally above 60. 



The preceding experiments were made with sea-water j but he 

 now made use of other water, into which he put common or sea. 

 salt, till he found by an hydrometer that it was of the same speci. 

 fie gravity with the sea-water ; and, at the same time, in another 

 gallon of water, he dissolved two pounds of salt, and into each of 

 these waters he put a small fresh herring. The next evening the 

 whole surface of the artificial sea-water was luminous without be- 

 ing stirred ; but gave much more light when it was disturbed. It 

 appeared exactly like the real sea.water in the preceding experi- 

 ment ; its light lasted about the same time, and went off in the same 

 manner : while the other water, which was almost as salt as it 



