J 62 On the Light emitted ly rotten tVood 



adopted a proper method, when, in some of his processes, 

 he destroyed the phosphorescence by sudden heating, in 

 order that, by comparing it with that of other wood not 

 treated in the same manner, he might observe whether it 

 effects the diminution of the gas as a hmiinous or as a pu- 

 trescent substance. For it appears to me very probable, that 

 bv such a violent exaltation of temperature, besides the phos- 

 phorescence, the previous degree of putridity is changed, and 

 consequently that this wood can neither decompose nor ab- 

 sorb any more oxygen gas. 



This alteration of phosphorescent wood, by means of 

 which its light is more or less speedily checked by certain 

 mediums, appears to me, with some probability, to depend 

 on the circumstance whether they are calculated more or 

 less to check the putridity, or, on the contrary, to promote 

 it. The putridity, therefore, and the phosphorescence con- 

 nected with it, must continue not only in oxygen gas but 

 also in atmospheric air, and in weak solutions of muriate 

 of soda and nitrate of potash. Like the phosphorescence of 

 wood, it is more or less cheeked by want of oxygen gas, and 

 consequently in all the non-respirable gases, and particu- 

 larly in nitrous gas, and in carbonic acid gas on account of 

 its peculiar property of opposing putridity ; also by ex- 

 posure to heat, on account of the desiccation connected 

 with it ; by concentrated or diluted acids ; by tartarons 

 acid, 8cc. The latter acts, perhaps, so far as it speedily at- 

 tracts the water, and therefore desiccates the rotten wood. 

 But whether sulphuriz'cd hydrogen gas, ammoniacal eas, 

 muriatic acid gas, which are all speedily niiseible with water, 

 jcxercise a prejudicial action on luminous wood bv absorbing 

 its moisture and acting in the same manner as fiuid ammo- 

 nia or acids ; or whether, by means of a peculiar antipu- 

 trescent property, they extinguish the phosphorescence so 

 speedily^, I will not venture to determine. 



In a word, this theory harmonizes pretty accurately with 

 the well known experiments on phosphorescence, which 

 continues in ir^ediums that promote putridity, and is inter- 

 rupted by fluids that oppose it. According to the above- 

 mentioned opinion of Carradori, this philosopher seems to 

 jiave considered such action as possible, but he does not 

 assign any cause. 



The following observations of M. Humboldt, which he 

 >vrote however for a totally different object, I found so ap- 

 plicable, with a few variations which may be easily made, 

 ^0 the conjectures I have expressed on the luminous appear- 

 ^ice of rotten wood;, which continues in some mediums 



and 



J 



