H8 On the light emitted I"/ rotten H'ood 



3dly, To render sensible the differences which exist be- 

 tween the large teeth ot" the crocodile of the Nile and those 

 of the crocodile of St.Doniinsro. 



XXIV. Olservations and Experiments on thfi Light emitted 

 I'll rotten Wood., in the different Kinds of Gas, and in 

 Fluids. By C. W. Bockman, of Carlsruhc, 



[Concluded fiom p. ;6.] 



JExpcriment X\'II. 



X INTRODUCED phosphoresccnt wood under the receiver or 

 the air-pump, placed a bit of it in a glass iilkd with water, 

 and another piece on a dish not innrierscd in water. When 

 the airbciian to be raretied, a (juantity of air not inconsider- 

 able issuccl from the wood. The light of tlte wood seemed 

 to be somewhat weaker than at first, and proportionahly less 

 than that of a piece placed without the receiver. When the 

 quicksilver in th^, baronieter connected with it sunk about 

 four lines, on the re-aduAission of atmospheric air 1 thought 

 I observed a considerable increase in the phosphorescence. 

 The piece of wood immersed in water was entirely pene- 

 trated bv that fluid : it therefore fell to the bottom, but 

 emitted as strong a light as at first. This experiment was 

 several times repeated with the same result. 



Experiment XVIII. 



Oval o-]as5 flasks, capable of containing five cubic inches, 

 and of equal thickness, were filled ; some with oxygen gas, 

 some with azotic gas, and some Vv'ith carbonic acid gas^ Slid 

 well stopped with corks, to which were affixed v.ires sup- 

 porlino; pieces of phosphorescent wood. I then introduced 

 ail these vessels at the same time into water at JCf of Reau- 

 mur. In about three-quarters of a minute the light in the. 

 carbonic acid gas perceptibly decreased, and then that in the 

 azotic ga'3 ; in one minute and a half it appeared weaker in 

 the oxygen gas ; and in two minutes and a half the least 

 phosph'oresce'ice w as not to be observed in any of the vessels. 

 It could not afterwards be revived in any of the pieces of 

 wood by any means whatever. This experiment was also 

 repeated several times with the like result. 



Experiment XIX. 

 Rotten wood (;mitted light in spring water, in boiled water, 

 aiid in distilled water, kept in a close vessel till the experi- 



jaclit 



i 



