24 ART. 3. — SEnCHI KAWAMUBA : 



For the spectrum analysis, the fungus-light is so feeble that, 

 when the slit of the spectroscope is made very narrow, it can not 

 be perceived. I have therefore made use of the flashes of a dry- 

 battery electric lamp, which was switched on and off, for showing 

 the scale on the spectrum of the fungus -light. The latter occupied 

 about the middle third of the solar-spectrum, i.e. the orange, the 

 yellow and the green. 



IX. Intensity of the Fungus-light. 



The following account will give an idea of the intensity of 

 the fungus light. 



By the aid of light from a luminous piece of the fungus, 

 about 100 sq. cm. in size and placed close by, I could well re- 

 cognize with the naked eye complex Chinese characters of a size 

 1 cm. or more across and Roman alphabets about 0*8 cm. large. 

 The letters were much more readily distinguishable when seen 

 under a magnifying glass. 



As to the determination of distance at which the naked eye 

 can perceive the fungus-light, experiments were made in rooms 

 which were made pitch dark. The fungi of different sizes could 

 be easily recognized at a distance of thirty metres. They could 

 be counted if placed 20 — 25 cm. apart from one another. When 

 their positions were changed, the movement could be followed 

 without difficulty. At a distance of thirty metres, however, the 

 light from a piece 7 cm. in longest diameter could not be distinctly 

 recognized. A larger piece 14 cm. in longest diameter could be 

 recognized at a distance of thirty-two metres, but not at a greater 

 distance. Although the luminous area of the latter piece was 

 about six times as large as that of the former, yet the greatest 

 distances at which they could be perceived differed only two metres. 



