518 History of Luminescence 



by white water or colored water. These records, with references, 

 have been collected by C. G. Ehrenberg (1834) and by A. Boue 

 (1869) , and will not be recounted here. 



At the begining of the eighteenth century reports of phosphores- 

 cence of the sea had reached such a point that the French Academy 

 of Sciences considered it necessary to warn the public against too 

 sensational reports of luminescence, under the heading: ^* " Another 

 fiction of an uncommon shining of the sea." The communication 

 was based on 



a letter from Cadiz, importing, that for 15 nights together they had seen 

 the whole sea shining with a clear light, almost like a liquid Phosphorus; 

 and to make this comparison the more perfect, the sea water being car- 

 ried away in bottles, gave the same light in the dark; that some drops 

 of it being let fall on the ground shone like sparks of fire, and that linnen 

 dipt in this water became also luminous. The fact having been well 

 examined, is found to be false. At most this report, which was spread 

 even in Spain, might be founded on some particular and lively colour, 

 which the sea might have at sunsetting. The academy think, they do as 

 much service to the publick, in disabusing them with regard to false 

 wonders, as in recounting to them the true. 



All the statements in the Cadiz account could have been true and 

 it is rather surprising to find the French Academy taking the stand 

 it did. 



Despite the warning of the French Academy in Paris, so mtich 

 interest in luminescence had been aroused that the Bordeaux 

 Academy of Sciences offered a prize in 1716 for the best essay on 

 the cause of natural and artificial phosphors. The prize was won 

 by J. J. D. de Mairan, perhaps best known for his work on the 

 aurora borealis. De Mairan's dissertation was Sur la Cause de la 

 Lumiere des Phosphores et des Noctiluques, Bordeaux, 1717, a fifty- 

 four-page essay. He maintained that sea light was not a reflection 

 but a true light emission, although the cause was not explained. It 

 was most apparent when the sea was oily {grasse) . De Mairan also 

 recognized the luminous " pulmon marine " (jellyfish) as a source 

 of light, and attributed luminescence in general to movement of 

 " sulphur," great enough to disengage the sulphur from surrounding 

 material. 



^* From vol. 2, p. 13 of The philosophical history and memoirs of the Royal Academy 

 of Sciences at Paris, Or an abridgment of all the papers relating to natural philosophy 

 which have been published by the ynembers of that illustrious society, from the year 

 1699 to 1720, a five- volume work by John Martin and Ephraim Chambers, published 

 in London in 1742. 



