Marvels of the Universe 



317 



ANTHELIA 



Such is the name given to a phenomenon which is only rareh-- observed. Certain climatic conditions 

 are necessary for its appearance. There must be a great deal of humidity in the atmosphere and 

 the sun's rays must fall obliquelv — that is to say, the sun itself must have only just risen. The usual 

 form which the atmospheric moisture takes is that of a bank of fog, and as the condensation of 

 vapour takes place more rapidlv in high latitudes, Anthelia are most likely to be observed in 

 mountainous regions. Suppose the reader has access to such a locality ; let him climb some 

 mountain and wait for the break of day. Looking to the west, a great white bank of fog hides the 

 neighbouring hills, while the sun's rays are just piercing the eastern mist. Should fortune favour 

 him he will see before him his own self silhouetted against the white background ; but Nature has 



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mwimmw 



Phnloha] ' {W. SariUe Kent. 



THE SUCKING FISH. 



This is one of ihc laziest fishes on record: for while equipped with every means for obtaining its own livelihood, it prefers to 

 attach itself by means of the strange oval sucker on its head to some object that will carry it within reach of its prey. 



endowed him with more than earthly beauty. Round his head appears a complex halo formed 

 by ring after ring of rainbow hues, shading from an outer rim of crimson or violet to an inner circle 

 of fine green, while the interspaces between the rings shade to yellow. The outermost of these 

 four concentric rings is white and fades away till it is lost in the cloud, but only occasionally does 

 this evanescent circle appear at all distinctly. Sometimes the range of colouring is reversed, the 

 red light forming the inner shade and green the outer ; but the exact reason for this contrast has 

 not yet been accurately ascertained ; it is possibly due to some law of diffraction which has still to 

 be discovered. The general course of the phenomenon, however, is simply diffraction, the sun's 

 rays being reflected at a peculiar angle by the minute globules of moisture of which the fog is com- 

 posed, while the reason of the apparition being noted by the observer is that the sun's rays, streaming 

 from the east, are in exact contact with his centre of vision. It is owing to this circumstance that 

 his shadow is thrown on the western bank of clouds. 



As may be supposed, the appearance of the perfect concentric rings is only possible in wide 

 atmospheric spaces. 



