io Dr. Young's Experiments and Calculations 
“ defined : under this was an arch of green, the upper part of 
“ which inclined to a bright yellow, the lower to a more dusky 
“ green : under this were alternately two arches of reddish 
“ purple, and two of green : under all, a faint appearance of 
ee another arch of purple, which vanished and returned several 
“ times so quick, that we could not readily fix our eyes upon it. 
“ Thus the order of the colours was, i. Red, orange-colour, yel- 
“ low, green, light blue, deep blue, purple, n. Light green, dark 
“ green, purple, m. Green, purple, iv. Green, faint vanishing 
“ purple. You see we had her.e four orders of colours, and per- 
“ haps the beginning of a fifth : for I make no question but that 
“ what I call the purple, is a mixture of the purple of each of 
“ the upper series with the red of the next below it, and the 
“ green a mixture of the intermediate colours. I send you not 
“ this account barely upon the credit of my own eyes ; for there 
“ was a clergyman and four other gentlemen in company, 
“ whom I desired to view the colours attentively, who all 
“ agreed, that they appeared in the manner that I have now de- 
** scribed. There are two things which well deserve to be taken 
“ notice of, as they may perhaps direct us, in some measure, to 
“ the solution of this curious phenomenon. The first is, that the 
“ breadth of the first series so far exceeded that of any of the 
“ rest, that, as near as I could judge, it was equal to them all 
“ taken together. The second is, that I have never observed 
“ these inner orders of colours in the lower parts of the rainbow, 
“ though they have often been incomparably more vivid than 
“ the upper parts, under which the colours have appeared. I 
“ have taken notice of this so very often, that I can hardly look 
“ upon it to be accidental; and, if it should prove true in general, 
“ it will bring the disquisition into a narrow compass ; for it will 
