L E T T E R VI. 143 



around fuch beautiful Lights, and Colours, and 

 Rainbows, as are much eafier imagined than ex- 

 prefTed by my poor Pen. Purchas^ in his Rela- 

 tion of the two Holjiein Embaflador's Travels in- 

 to Perfia^ by way of Narva^ gives much the 

 fame account of it. And perhaps you may judge 

 that it does, in a good meafure, refemble the fa- 

 mous Cafcade of T'erni in Italy ^ though it does 

 not fall from fo high a Precipice ^ vid. MiJJbfi^ 

 vol. 2. pag. 363. whofe words are as follow, ijiz, 

 *^ The River Velino throw^s itfelf down from a 

 ^^ fteep Rock, three hundred foot high, and falls 

 *^ into the Cavity of another Rock, againft which 

 " the Water daflies with fuch violence, that it 

 *^ rifes like a Cloud of Water-duft, perhaps double 

 " the heigth of the Fall 3 and caufes a perpetual 

 " Rain in all the adjacent Parts. This pulverized 

 " Water forms, with the Sun, an infinite num- 

 " ber of Rain-bows, which encreafe and diminifh, 

 *' crofs one another, and dance about according 

 " to the various rebounding and Ipurting up of 

 " the Water; and as this watry Smoak is tliicker 

 *^ or thinner. While they are Hill in the Air, they 

 " break, foam, dafh againft, encounter, and ihock 

 " each other, and feem to be entangled together/ ' 

 The Author here, you fay, muft be miftaken^^ 

 for it contradicts Sir Ifaac Nevjton\ Theory of 

 Colours: Sir Jfaac Newton is not infallible. The 

 Reafon why the Water-duft at Narva is lefs, and 



rifes 



