422 On tht Light from organifed Bodies. 



of the philofopher more particularly to this fubje£l, and of communicating his own ex- 

 periments and obfervations upon it, to this learned Society. 



By the fpontaneous emiflTion of this light, the author wiflies to dlftinguifli it from all 

 kinds of artificial phofphorus j which, as he apprehends, differ eflentially, in fome of 

 their properties, from that light of which he means to treat. And, by its adhefion to 

 bodies with fome degree of permanency, he diftinguifties it from that tranfient fort of 

 light which is obfervable in ele£tricity, in meteors, and in other lucid emanations. The 

 light which is the fubjeft of this paper, he fliall therefore beg leave to difcriminate by the 

 name of fpontaneous light. 



The fubftances from which fuch light is emitted, are principally the following. 



Marine animals, both in a living ftate, and when deprived of life. As inftances of 

 the firft maybe mentioned, the (hell-iifh aWzi pholas, thz medufa pho/phorea, and various 

 other mollufca. 



When deprived of life, marine fifhes in general feem to abound with this kind of light. 

 The honourable Mr. Boyle commonly obtained light, for his ufe, from the whiting, ae 

 appears from many parts of his works : the author of thefe experiments and obfervations 

 procured his fi(h light chiefly from the herring and the mackerel. 



The flefh of quadrupeds has alfo been obferved to emit light. Inftances of this are 

 mentioned by Fabricius ab Aquapendente ,- by T. Bartholin ; by Mr. Boyle ; and by Dr. 

 Beale } for which, fee T. Bartholin, de Luce Animalium, p. 183; Boyle's Works, 

 Vol. III. p. 304; Phil. Tranf. Vol. XI. p. 599. 



In the clafs of infe£fs are many which emit light very copioufly, particularly feveral 

 fpecies of fulgora or lantern-fly, and of lampyris or glow-worm ; alfo the fcolopendra 

 eleBrica ; and a fpecies of crab, called cancer fulgens. 



Rotten wood is well knovi^n to emit light fpontaneoufly. Peat earth alfo has the fame 

 property. Of the effects of the latter, a remarkable inflance is related in Plot's Natural 

 Hiftory of StafFordlhire, p. 115. 



,The place where the following experiments were made, was a dark wine-vault, 

 which, for diftindlion's fake, the author calls the laboratory. The heat of this laboratory 

 varied, throughout the year, from about 40 degrees of temperature to 64°. The ther. 

 mometer made ufe of was that of Fahrenheit. 



The weight is always to be fuppofed that called troy weight. The liquid meafure em- 

 ployed, was that ufed for wine in this country : the ounce containing 8 drams avoir- 

 dupois ; and the pint, 16 ounces. 



The water ufed in general for the experiments, was pure fpring water, drawn up from 

 under ground by means of a pump ; and it was always employed cold, unlefs otherwife 

 exprefled. 



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