3 i8 A TrVhATISE 



qualities in the Ayre : but are erasable bodies on the earth, 

 as all others, are, .which as yet wee have fbimdand havemed- 

 died withall : and are indeed, die, very bodies themfeives.eau- 

 f;ng fucheffecls upon our eye by reflecting f light, which wee 

 exprefleby the names of colours. 



, 



THE THIRTIETH CHAP. 

 Of luminous or afferent Ctlow*, 



t> A S for the luminous colours , whole natures art hath 



Apparitions /-\ made more maniabie by us, then thofe which are called 

 of colours JL Areall colours, and are permanent in bodies : their ge- 

 throBgh apnO ^ration is'cleercly to bee feene in rheprifme or triangular 

 SfSafie wof 8 jaf]fe wee formerl v mentioned. The confidering of which, 

 wvoforw, will confinnc our (Io6irine, that even the colours of bodies, 

 are but various mixtures of light and madorves , diverfly re- 

 flected to our eyes. For the right uaderftanding of them, 

 wee are to note, that this glafle makcth apparitions of colours 

 in two forts : the one, when looking through it there appeare 

 various colours in the objects you looke upon ( different from 

 their rcall ones ) according to thepofitionyou hold the glafle 

 in when you looke upon them. The other fort is, whea the 

 beames of light that pafle through the g'afle, areas it were 

 tinned in their paflage , and are caftby theglaffe upon fbme 

 fblid objecl: , and doe appeare there in fuch and fsch colours, 

 which doe continue liill the fame, in what pofitionfbever you 

 ftand to look upon themjeither before, or behmd^r on any fide 

 ofthe glafle. 



The fcverall Secondly,we are to note that thefe colours are generally made 



parts of the ob- by refraction (though fometimes it may happen orherwife, as 



jcamakefcve- above we have meunoned. ) To difcpverthereafonofthefir/f 



rail angles at lert of colours , that appeare by refaction when one looketh 



eir en " a c through the glaile : let us fuppofe two feverall bodies the one 



c black, the other white, lying clofe by one an other andinrhe 



fame horizoDtall parallcle : but fb, that the black be further 



from us then th white ; then, if we hold theprifme through 



which we are to fee thefe twooppefitely coloured bodies fome- 



what 



