PHYSICAL AND LITERARY. 77 



their brighter dyes till the fun is fome mi- 

 nutes fet J and that they pafs from yellow to 

 a flaming golden colour ; and thence, by 

 degrees, to red j which turns deeper and 

 deeper, tho' fainter, till th,e fun leaves them 

 altogether. Now, it is plain, that the clouds, 

 at that time, receive the fun's light thro',^ ^ 

 much longer tract of air than we do at 

 the inftant of fetting, perhaps by the differ., 

 rence of a hundred miles or more ; as may be 

 computed from their height or the duratiori 

 of their colours. Is it not, therefore,' na- 

 tural to imagine, that, as the fun's light be- 

 comes always fome what yellowifli or orange 

 in paffing thro' the depth of tlje'^ atinofphere 

 horizontally, it ought to incline' more and" 

 more from orange towards red, by paffihg 

 thro' a flill greater length of air ; fo that the 

 clouds, according to their different altitude, 

 may affume all the variety of colours, obfer-' 

 yed in them at fun-rifing and fetting, by 

 barely reflsding the fun's incident light as 

 they receive it ? I have often obferved with 

 pleafure, when in Swkzer/and, that the' 

 fnowy fummits of the ^Ips turn more and 

 more reddiili after fun-fet, in the fame 

 manner as the clouds. What makes the 



fame 



