THUNDER AND LIGHTNING. 



the system of rays themselves suffering no change of position. 

 The bow, thus presenting the appearance of an alternate motion 

 in a direction nearly horizontal, had usually the appearance of the 

 undulations or folds of a ribbon or nag agitated by the wind. 

 Sometimes one, and sometimes both of its extremities would 

 desert the horizon, and then its folds would become more numerous 

 and marked, the bow would change its character, and assume the 

 form of a long sheet o^rays returning into itself, and consisting of 

 several parts forming graceful curves. The brightness of the rays 

 would vary suddenly, sometimes surpassing in splendour stars of 

 the first magnitude ; these rays would rapidly dart out, and curves 

 would be formed and developed like the folds of a serpent ; then 

 the rays would affect various colours, the base would be red, the 

 middle green, and the remainder would preserve its clear yellow 

 hue. Such was the arrangement which the colours always pre- 

 served ; they were of admirable transparency, the base exhibiting 

 blood-red, and the green of the middle being that of the pale 

 emerald ; the brightness would diminish, the colours disappear, 

 and all be extinguished, sometimes suddenly, and sometimes by 

 slow degrees. After this disappearance, fragments of the bow 

 would be reproduced, would continue their upward movement, 

 and approach the zenith ; the rays, by the effect of perspective, 

 would be gradually shortened ; the thickness of the arc, which 

 presented then the appearance of a large zone of parallel rays, 

 -would be estimated ; then the vertex of the bow would reach the 

 magnetic zenith, or the point to which the south pole of the 

 dipping needle is directed. At that moment the rays would be 

 seen in the direction of their feet. If they were coloured, they 

 would appear as a large red band, through which the green tints 

 of their superior parts could be distinguished ; and if the wave of 

 light above mentioned passed along them, their feet would form a 

 a long sinuous undulating zone ; while, throughout all these 

 -changes, the rays would never suffer any oscillation in the direc- 

 tion of their axis, and would constantly preserve their mutual 

 parallelisms. 



"While these appearances are manifested, new bows are formed, 

 either commencing in the same diffuse manner, or with vivid and 

 ready-formed rays : they succeed each other, passing through 

 nearly the same phases, and arrange themselves at certain, 

 distances from each other. As many as nine have been counted, 

 having their ends supported on the earth, and, in their arrange- 

 ment, resembling the short curtains suspended one behind the 

 other over the scene of a theatre, and intended to represent the 

 sky. Sometimes the intervals between these bows diminish, and 

 two or more of them close upon each other, forming one large zone, 

 390 



