140 



probably from the accompanying increment of 

 temperature. The luminous matter continued to 

 shine, without alteration, in oxygen, nitrous oxide, 

 hydrogen, carbonic acid gas, cyanogen, olifiant gas, 

 and nitrous gas. When the insect was introduced 

 into pure oxygen, obtained from chlorate of potassa, 

 it did not seem more alert than before ; neither, in 

 repeated trials, was the luminosity perceptibly in- 

 creased. A glow-worm was not injured by being 

 introduced into a medium of hydrogen, nor did the 

 light undergo any change ; in carbonic acid it soon ex- 

 hibited signs of suffering, and expired in a bright 

 shroud of light it had no power to quench ; and this 

 light continued a considerable time after death. 



Light does not seem to exercise any control over 

 the luminous matter when reposing in oil of olives ; 

 indeed, a luminous spherule exposed for an entire 

 day to the sun-beam shone at night as usual, or with 

 slight decrease of intensity. A luminous spherule 

 held in the warm hand, say 98 F., for two minutes, 

 continued luminous as in ordinary circumstances ; it 

 was then introduced into oil of olives, where it shone 

 uninterruptedly. In water heated to 108 F., the lu- 

 minous matter continued to shine for more than a 

 minute ; in a temperature of 114 F., it became extinct 

 in about 40 seconds ; in 126, it was lost in 30 se- 

 conds ; in a temperature of 94, it became faint in 60 

 seconds, though it continued to emit light much 

 longer ; in a temperature of 99 F., the light was more 

 brilliant and beautiful than in any other to which the 

 luminous matter was submitted, and it continued more 

 intense for about 60 seconds than under any other cir- 

 cumstances. A glow-worm, not luminous, was intro- 

 duced into water at 64.5 F., but no light was emitted 

 at a temperature of 88, light was faintly emitted at the 



