| Description | 'There was produced a Manuscript of Mr Newton's, touching his Theory of Light and Colours; containing partly an Hypothesis to explain the Properties of Light, by him discoursed of and in his former Papers; partly the principal phaenomena of the various colours exhibited by thin plates or bubles esteemed by him to be of a more difficult consideration, yet to depend also on the said properties of Light.
Of the Hypothesis was onely read the first part, giving an account of Refraction, Reflection, Transparency and Opacity. The second part, explaining Colours, referred to the next meeting.
The author having prefaced that though he formerly purposed never to write any Hypothesis of Light and Colours, that so he might avoyd occasion of being engaged in vain disputes: yet having since considered that such an Hypothesis might much illustrate the papers now sent, he hath delivered one, yet not concerning himself, whether it shall be thought probable or improbable, so it do byt render thses ad the former papers more intelligile: The summe whereof is, That he needs not, for his purpose, to determine what Light is further, than that is something or other capable of exciting vibrations in the other; seing that thus it will become so general and comprehencive of other Hypotheses, as to leave littel room for new ones to be invented. Where yet he declares, that he shall not assume either this or any onther Hypothesis, not thinking it necessary to concern himself whether the 'Properties fo Light' discovered by him be explained by this or any ohter Hypothesis capable of explaining them; but saith, that while he is describing it, he shall sometimes speak, as if he assumed it and propounded it to be beleived. In discovering this Hypothesis he hath occasion to intimate the principal cause of the Cohesion of the parts fo Solids and Fluids; and the Springiness of Glasse and other bodies, whose parts slide not one uppon another in bending : as also of the standing of the Mercury top-full to a much greater hight than 29 inches.
He takes likewise occasion, to give light from this Hypothesis to that puzling Probleme, viz. By what means the Muscles are contracted and dilated to cause Animal motion.
Some of the Company taking particular motice, among other things, of an Experiment mentioned in this Hypothesis, desired it might be tryed; viz that having laid upon a Table a round peice of glasse abut two inches broad in a brasse ring , so that the glasse might be one third part of an inch from the Table: And then rubbing the glasse briskly, till some litle fragments of paper laid on the table under the glasse began to be attracted and move nimbly to and fro after he had done rubbing the glasse, the papers would continue a pretty while in various motions, sometimes leaping up to the glasse and resting there a while, the leaping down and resting there, and then leaping up and down again, and this sometimes in lines, seeming perpendicular to the Table, sometimes in oblique ones; sometimes also leaping up in one arch and leaping down in another divers times together without sensible resting between, sometimes skip in a bow from one part of the glasse to another withour touching the Table, and as if they had been carried about in the midst of a Whirlwind, and be otherwise variously moved; every paper with a divers motion. And upon sliding his finger upon the upper side of the glasse, though neither the glasse nor the enclosed air below were moved thereby, yet would the paers as they hang under glasse receive some new motion, inclining this or that way accordingly as he moved his finger.
This experiment, he proposes to be varied with a larger glasse placed further from the table, and to make use of bits of leaf-gold in sted of papers; esteeming that this will succeed much better, so as perhaps to make the gold rise and fall in Spiral lines, or whirle for a time in the air without touching either Table or Glasse.
It was ordered that this Experiment should be tryed the next meeting, and the Curator promised he would prepare it for that time.
The Secretary was ordered by letter to enquire of Mr Newton, whether he would not give way to take a copy of his Papers, for the better consideration of their contents. '
The Secretary exhibited Mr Willughby's 'Ornithologiae' sent by the Printer Mr Martin, which was delivered to the Curator for the Society's Library. |