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## A Letter of Mr. Franc. Linus, written to the Publisher from Liege the 25th of Febr. 1675. st. n. being a Reply to the Letter printed in Numb. 110. by way of Answer to a former Letter of the same Mr. Linus, concerning Mr. Isaac Newton's Theory of Light and Colours.

Honoured Sir,

More might be said out of the same Relation, to shew that the Image was not Transverse. For, if it had been Transverse, Mr. Newton, so well skilled in Opticks, could not have been surprised (as he says he was) to see the length therof so much to exceed the breadth; it being a thing so obvious and easie to be explicated by the ordinary Rules of Refraction. That other place also, in the next page 3007. (where he says, the Incident Refractions were made in the Experiment equal to the Emergent,) proves again that the said oblong Image was not Transverse, but Parallel. For it is impossible, the Transverse Image should be so much longer than broad, unless those two Refractions be made very unequal, as both the computation according to the common Rules of Refraction, and Experience testifie. Wherefore Mr. Newton had no reason to tax (in pag. 4091.) P. Pardies of Hallucination, for making in page 4088. those two Refractions very unequal: For, that learned Optike very well saw, that in a clear day so great an inequality of length and breadth could not be made, unless those two Refractions were also made very unequal. These places, I say, might be added to the former, and further here explicated if need were; but there being no need, I cease to detain you any longer herein.