VEGETABLE LAMPS. 137 



that I have ever seen. The luminous property continued, 

 though gradually diminishing, for four or five nights, when 

 it ceased on the plant becoming dry. We called some of the 

 natives, and showed them this fungus when emitting light. 

 The room was dark, for the fire was very low and the candles 

 extinguished; and the poor creatures cried out, 'Chinga,' 

 their name for a spirit, and seemed afraid of it." 



A very attractive agaric, Agaricus olearius (Plate XIII.), 

 is found at the foot of olive-trees in Southern Europe. 

 During the daytime the color is yellow, but observed at 

 night it emits a brilliant blue light. Like the Australian 

 species, it continues to emit light after it has been taken 

 from the ground, the phosphorescence persisting for succes- 

 sive nights. So brilliant are the gleams, that they may be 

 perceived at times before darkness sets in. Experiment 

 showed that the light was extinguished when the tempera- 

 ture was below -f- 90 to -f- 6 C. ; but the luminosity was 

 not destroyed, as it re-appeared when the temperature was 

 raised above this point. If kept some time in a temperature 

 below freezing, it loses its light-emitting property entirely. 

 It gleams as brightly under water as out; pure oxygen 

 seems to have no effect upon it, and the most careful experi- 

 ments fail to show the slightest elevation of temperature 

 about the parts which shine. The light seems to emanate 

 from the head (pileus) of the fungus, the lamellce of the 

 latter, where the seeds are found, being the centre of 

 the luminous phenomenon. 



These interesting light-givers are perhaps more common 

 than we are aware of, from the fact that nocturnal investi- 

 gations in the woods are not frequent, nearly all the discov- 

 eries being the result of accident. A small, luminous fungus 



