METEOROLOGY. 



head. The inhabitants of the above city, struck with awe at 

 so rare a phenomenon, vented their curses on the learned 

 Marquis of Valle-Umbroso, who formed the hazardous resolu- 

 tion to attack their prejudices. I therefore left the persuasion 

 they entertained, to make all the impressions which are usual 

 in these cases ; and endeavoured to explore the cause of the 

 above-mentioned phenomenon, which I believe to be as follows. 



*' The spring was very rainy, and even on several days 

 during the summer, a greater quantity of water fell on the 

 coast than in the severest winter. It is natural to suppose that 

 the abundant rain, combined with the great humidity of this 

 valley, must have impregnated the earth with infinite vapours, 

 which, being blended with so many other exhalations, would 

 rise into the atmosphere, volatilized by the heat produced, as 

 well by the perpendicular diredlion of the solar rays in summer, 

 as by the commotion of the central fire introduced by them- 

 selves into the present station. The heights there occupied by 

 the aforementioned vapours must have been proportionate to 

 their different specific gravity, by which they would equilibe- 

 rate themselves with the columns of the aerial fluid. Thus 

 some would rise to the upper part, while others would remain 

 in the lower. 



" The winds which, from the eastern quarter, are wont to 

 blow gently at five in the evening, wandering and without any 

 particular destination, having united them in such a way as 

 that they appeared to be equally distant in every part at sunset, 

 the imagination figured this arc. The tranquillity which pre- 

 vailed, and the mutual attra6tion between some of the cor- 

 puscles and the others, kept them stationary, until the east 

 wind, blowing with some degree of force, at the rising of the 



moon. 



