Shining Fish, Flesh, and Wood 483 



phosphor, to explain how the light of wood comes from the move- 

 ment of air within it. 



This also explains why dry wood loses the quality of shining, for the 

 pores are wider and provide an easier passage for the air, without such 

 frictions as was formerly required. A large amount of these particles of 

 air passing from these wide pores results in a gradually weakening light, 

 until it finally disappears altogether . . . though by the addition of new 

 moisture the pores become narrower. 



Albrecht certainly had a very definite theory. 



BARON VON MEIDINGER 



In 1777 Baron von Meidinger wrote from Vienna on the light of 

 damp wood and presented a theory of light, which, although based 

 on only a few experiments, actually came very near the truth. He 

 had noticed that many different kinds and samples of wood but not 

 all samples might develop luminosity if moist. The light came from 

 bright specks or strands and disappeared when the wood dried out, 

 but did not reappear on again moistening the sample. ^° The light 

 was obviously similar to that of the St. Johanniswtirm (Lampyris 

 noctiluca) and von Meidinger thought it might be due to little 

 insects on the wood,^^ especially as Baker (1742) had observed the 

 light of the sea to be due to insects. However, an examination of 

 the wood with a good microscope revealed nothing. Therefore the 

 Baron drew three conclusions: (1) The light must come from ani- 

 malcules (Tierchen) , too small to be seen with the highest powers 

 of the microscope, with many millions together producing the light. 

 (2) These animalcules must appear only when the wood reached a 

 certain degree of rottenness and need not necessarily attack all sam- 

 ples. (3) They must light only as long as they are alive. Since 

 drying kills them, drying also destroys the ability of the wood to 

 luminesce. Had von Meidinger used the term " fungus mycelium " 

 instead of " animalcule " he would have been quite correct. 



^° M. Sage (1780) also emphasized the necessity of water for phosphorescence of 

 oak timbers in a bridge at Chaton, a village on the Seine. The light disappeared and 

 returned on moistening. 



^^ A similar idea was expressed in 1780 by M. Gioanetti, who investigated a reported 

 luminous phenomenon in the water of Eglise, a hamlet in Fontanemore parish in the 

 Duch^ d'Aoste. He found no light in the water but bright luminous specks in the 

 mud, which were little animals, perhaps " nymphs of luminous flies." He remarked 

 that perhaps luminous wood contained luminous animalcules also. The observations 

 were published in the Journal de Physique 15: 495-496, 1780. 



