Newtons prism experiments showed that white sunlight is made up of?

Electromagnetic radiations which ranged in appearance from red to violet. He did not see beyond the visible spectrum - into the infra red and lower frequencies, nor ultra violet and higher frequencies.

It is understood that he initially defined the spectrum as consisting of 4 colours but later, to bring it in line with the musical scales, the spectrum was split into seven colours. The spectrum is, of course, a continuum, consisting not of 4 nor 7 but an infinite number of colours.