CHAPTER XLIX. 

 PHYSICAL GEOGRAPHY. METEOROLOGY (continued}. 



ATMOSPHERIC PHENOMENA THUNDER AND LIGHTNING AURORA BOREA- 



LIS THE RAINBOW MOCK SUNS AND MOCK-MOONS HALOS FATA 



MORGANA REFLECTION AND REFRACTION MIRAGE SPECTRE OF 



THE BROCKEN. 



THERE are a great number of interesting, and "to inhabitants of these 

 islands uncommon, perhaps we might say fortunately uncommon, pheno- 

 mena, which overtake the traveller in other countries. We have referred to 



Fig. 724. The Waterspout. 



whirlwinds and tornados, and will now mention two phenomena connected 

 with these storms. There is the water-spout, for instance, and sand-pillars 

 in the desert, which are whirled up by these winds in spiral columns of 

 water and sand respectively. The tiny whirlwind at cross-roads, which picks 

 up straws and leaves, is the common appearance of whirling or crossing 

 currents of air. 



