Sentence:  And seeing the Rays which differ in Refrangibility may be parted and <WSD>sorted</WSD> from one another, and that either by Refraction..., or by Reflexion..., and then the several <WSD>sorts</WSD> apart at equal Incidences suffer unequal Refractions,...; it's manifest that the Sun's Light is an heterogeneous Mixture of Rays..., as was proposed. 
Meaning of the word marked with <WSD> tags:  (separate according to certain criteria)  To separate items into different categories according to certain criteria that determine their sorts.