ANIMAL AND VEGETABLE PHOSPHORI. 115 



particular colour, but only light that was perceived in this case. lie 

 then dippod boards painted with the different colours, and also glass 

 tabes, filled with substances of different colours, in water rendered 

 luminous by fishes. Tn both these rases the red was hardly visible, 

 the yellow was the brightest, and the violet the dullest. But on 

 the boards the blue was nearly equal to the yellow, and the green 

 more languid ; whereas in tbe glasses, the blue was inferior to the 

 green. 



Of all the liquors into which he put the phloades, milk was ren- 

 dered the most luminous. A single phloas made seven ounces of 

 milk so luminous, that the faces of persons might be distinguished 

 by it, and it looked as if it was transparent. 



Air appeared to be necessary to this light; for when Beccaria 

 put the luminous milk into glass tubes, no agitation would make it 

 shine, unless bubbles of air were mixed with it. Also Monti and 

 Galeati found, that, in an exhausted receiver, the phloas lost its 

 light, but the water was sometimes made more luminous ; which 

 they ascribed to the rising of bubbles of air through it. 



Beccaria, as well as Reaumur, had many schemes to render the 

 light of these phloades permanent. For this purpose he kneaded 

 the juice into a kind of paste, with flour, and found that it would 

 give light when it was immersed in warm water ; but it answered 

 best to preserve the fish in honey. In any other method of preser- 

 ration, the property of becoming luminous would not continue 

 longer than six months, but in honey it had lasted above a year ; and 

 then it would, when plunged in warm water, giye as much light as 

 eyer it had done. 



Similar, in some respects, to those observations on the light of 

 the phloas, was that which was observed to proceed from wood 

 which was moist, but not in a putrid state, which was very conspi. 

 cuous in the dark. 



That the sea is sometimes luminous, especially when it is put in 

 motion by the dashing of oars or the beating of it against a ship, has 

 been observed with admiration by a great number of persons. Mr, 

 Boyle, after reciting all the circumstances of this appearance, as 

 fur as he could collect them from the accounts of navigators; as its 

 being extended as far as the eye could reach, and at other times 

 being visible only when the water was dashed against some other 

 body ; that, in some seas, this phenomenon is accompanied by soma 

 particular winds, but not in others ; and that sometimes on part of 



