114 ANIMAL AND VEGETABLE PHOSPHORI. 



of attention. That this fish is luminous was noticed by Pliny ; 

 wha observes, that it shines in the mouth of the person who eats it, 

 and, if it (ouch his hands or clothes, makes them luminous. He 

 also says, that the light depends upon its moisture. 



Reaumur observes, that, while other fishes give light when they 

 tend to putrescence, this is more luminous in proportion to its 

 being fresh; that when they are dried, their light will revive if 

 they be moistened either with fresh or salt water, but that brandy 

 immediately extinguishes it. He endeavoured to make thrs light 

 permanent, but none of his schemes succeeded. 



The attention of the Bolognian academicians was engaged to thi* 

 subject by M. F. Marsigli, in 1724, who brought a number of 

 these fishes, and the stones in which they were inclosed, to Bologna, 

 on purpose for their examination. 



Beccaria observed, that though this fish ceased to shine when it was 

 putrid, yet that in its most putrid state, it would shine, and make 

 the water in which it was immersed luminous, when they were agi- 

 tated. Galeati and Monti found, that wine or vinegar extinguish, 

 ed this light: that in common oil it continued some days ; but 

 in rectified spirit of wine or urine, hardly a minute. 



la order to observe in what manner this light was affected by 

 different degrees of heat, they made use of Reaumur's thermome- 

 ter, and found that water rendered luminous by these fishes in- 

 creased in light till the heat arrived to 45 degrees ; but that it then 

 became suddenly extinct, and could not be revived. 



In the experiments of Beccaria, a solution of sea salt increased 

 the light of the luminous water, a solution of nitre did not increase 

 it quite so much ; sal ammoniac diminished it a little ; oil of tartar 

 per deliquium nearly extinguished it; and the acids entirely. This 

 water poured upon fresh calcined gypsum, rock crystal, ceruss, or 

 sugar, became more luminous. He also tried the effects of it when 

 poured upon various other substances, but there was nothing very 

 remarkable in them. Afterwards, using luminous milk, he found 

 that oil of vitriol extinguished the light, but that oil of tartar in. 

 creased it. 



This gentleman had the curiosity to try how differently-coloured 

 substances were affected by fliis kind of light ; and having, for this 

 purpose, dipped several ribbons in it, the white came out the 

 brightest, next to this was the yellow, and then the green ; the 

 other colours could hardly be perceived. It was not, however, any 



