Sir Isaac Newton’s laws of motion, circa 1600’s, gave the description of how the force of gravity varied with distance, following the inverse distance squared equation, but he did not propose a cause for gravity or inertia in any of his publications. Although, the following quote, from a private letter to Robert Boyle, shows Newton did conceive of a cause for gravity that is essentially the duplicate of this radiation and shadowing model of remote forces. If Newton’s term “ethereal spirit” is replaced with the term “prime radiation” in the following quote, the similarity of the concepts becomes obvious.
Quote: “so may the gravitating (apparent) attraction of the Earth be caused by the continual condensation of some other suchlike ethereal spirit (prime radiation),. . . in such a way . . . as to cause it (this spirit) (prime radiation) from above to descend with great celerity (speed) for (from) a supply; in which descent it may bear down with it the bodies it pervades, with force proportional to the superficies (surfaces) of all their parts (atoms) it acts upon.” Unquote
The terms in above brackets have been added to the original to aid in the comparison. It is satisfying and important to note that Newton’s concept, as stated above, does not propose an Aether consisting of the vibration or flow of particulate material, nor does it propose attraction through a distance as a cause. In this author’s opinion the above quote shows that Isaac Newton did frame a non-particulate radiation and shadowing system as a cause for gravity, circa late 1600’s.