Shining Fish, Flesh, and Wood 479 



Eighteenth-Century Views 



J. J. DORTOUS DE MAIRAN 



During the early part of the eighteenth century more or less 

 sporadic discussion of shining wood and fish took place. William 

 Derham, F. R. S. (1657-1735), the English divine and natural phi- 

 losopher, included in his Philosophical Experiments and Observa- 

 tioy-is of the Late Eminent Robert Hooke, S. R. S., and other Eminent 

 Virtuosos in his Time (London, 1726) printed directions for find- 

 ing shining wood (p. 176) , as follows: 



The author occasionally speaking of shining Woods, delivers this Rule 

 for the future finding of them. That an Apple-Tree is the best wood; 

 that it must be very dry, or rotten; that being so and lying under ground, 

 that part under ground will partake of a shining Quality, which will 

 not last above three Days, nor to be recover'd again when lost. 



In the prize essay by de Mairan (1717) , the attempt was made to 

 explain shining wood and flesh in terms of his general belief that 

 light of " phosphores " and " noctiluques " results from anything 

 which puts their " sulphure " in movement. Possibly this idea is a 

 reflection of the observation that stimulation or agitation excited 

 the luminescence of animals. De Mairan believed that the cohesion 

 of a substance normally prevents the movement of its sulphur, but 

 when the natural agitation of the sulphur is sufficient to be trans- 

 mitted to the surrounding material, the sulphur breaks from its 

 prison and light appears. Matter which contains much sulphur be- 

 comes luminous by fermentation alone, like flesh and the skin of 

 fishes. Wood is stronger and much more compact than the skin of 

 animals and hence does not become luminous until it is thoroughly 

 rotten. De Mairan may not have been correct in attributing the 

 light to agitation of a fiery principle, but he did have a definite 

 theory which he attempted to apply to all types of luminescence. 



HENRY BAKER 



In the middle of the century, when speculation regarding the 

 cause of phosphorescence of the sea was at its height, interest in 

 fish luminescence revived. It is possible that Henry Baker, whose 

 book. The Microscope Made Easy (London, 1742: 242) had aroused 

 popular interest in microscopic things, may have given the first 

 hint that the light of fish, flesh and wood was due to microscopic 

 organisms. 



