io8 Voyage of the Novara 



from the Azores to the Cape Verde Islands, and which are 

 of still more frequent occurrence in the summer of the north- 

 ern hemisphere. 



We kept Madeira, or rather the clouds which, during the 

 summer, gather daily round the mountains, a long time in 

 view; and on the 19th, at a distance of 120 miles from the 

 island, some persons on board thought they could still distin- 

 guish them. 



We steered at first in a south-westerly direction, with light 

 breezes and fine weather. Advancing, however, towards the 

 limits of the trade-winds, showers became frequent, and the 

 wind chopped about much oftener ; a more southerly course 

 was therefore taken, in order to come as soon as possible 

 under the influence of the north-easterly trade-winds. 



There was now an opportunity of directing attention to the 

 formation of the clouds, which, in these latitudes, assume at 

 times very curious appearances. The cirri disappeared by 

 degrees, and the cumuli towered up on the horizon in colossal 

 masses. These latter are formed under the influence of the 

 sun, when most powerful, and are therefore seen chiefly during 

 the afternoon. As soon as they rise they vanish by absorp- 

 tion, just as fast as they are formed by evaporation from the 

 sea. Rain very rarely proceeds from them. The alternation 

 of their shades, tints, and colours, is beautiful in the extreme, 

 particularly at sunset, when their outlines, as they stand out 

 in bold relief on the clear blue sky, vary in hue from the 

 deepest grey to the most brilliant golden yellow. 



