IGNIS FATTTUS. 143 



blue ; every star blazes like a diamond ; and the 

 light of the moon, of which every particle is sent 

 down through the pure air, well deserves Milton's 

 epithet of "peerless." It is so bright and silvery, 

 and so gratifying, without being the least painful to 

 the eye, that it is probably the most glorious sight 

 in nature. But it can be seen only at some distance 

 from the unfrozen sea, and the collected habitations 

 of men, as there is always some action in the atmo- 

 sphere at such places. 



Moonlight is not the only instance that we have 

 of cold light ; for the first beginnings of flame, in sub- 

 stances that are easily kindled, and also the last 

 glimmers of smouldering fires, are cold and blue as 

 compared with the light of vigorous combustion. 

 That may be seen in the lighting of a common 

 match, the flame of the easily burnt sulphur on which 

 is cold and blue in comparison with the flame after 

 it has reached the splinter of wood. Phosphorus, 

 and also those substances which give out lights that 

 are called phosphorescent, are also cold and blue. 

 One of the most remarkable of these is the IGNIS 

 FATUUS, or " Lantern Jack," which floats over 

 marshy places, and in all probability, consists of 

 hydrogen gas combined with phosphorus and sul- 

 phur, which, being exceedingly inflammable, may be 

 set on fire by the friction of the air in a breeze too 

 gentle for agitating the branches or rustling the 

 leaves. The motion of a human being through an 

 atmosphere strongly impregnated with those highly 

 inflammable gases, may be sufficient to produce a 

 train of the cold blue flame. It is from the decom- 

 position of animal and vegetable matter that those 

 gases are produced. The quantity of small ani- 

 mals chiefly of the insect tribes, that are continu- 

 ally perishing in marshes by falling from their 

 island-habitations in their rushes and reeds into the 

 water between, is much greater than would readily 

 be supposed ; and when those waters are shallow, 

 and the air and light in consequence act powerfully 



