Christiani Hugenii Zelemii, dum viveret, toparchae opuscula postuma, quae continent dioptricam. Commentarios de vitris figurandis. Dissertationem de corona & parheliis. Tractatum de motu. De vi centrifuga. Descriptionem automati planetarii

...that the table which we have given here deviates slightly in magnification from the Author's table. For in that one, he had posited the magnification in a 30-foot telescope to be as 120 to 1, whereas, given the focal distance of the ocular lens as 3 1/3 inches, as the Author does, it is only as 109 to 1; according to which ratio we have constructed the rest of the tables regarding magnification.

Finally, he approaches Microscopes, first the simple ones, then the compound ones, and in each he determines the magnification of the object. Assuming a properly ordered microscope, as he had done with telescopes, and considering both aberrations—both that which is from the figure and that which is from the dissipation of rays—by comparing this with the others, he finds any other [microscope] in which neither aberration causes harm, given the focal distance of the ocular lens and the magnification of the object.

Our author, while considering the Newtonian dissipation of rays, speaks as if the distance on the axis of the lens between the two points—toward one of which the red rays tend, and toward the other the violet ones—is 1/35 of that distance which is between the point to which the red rays belong and the lens itself. So that this is not misunderstood, it must be considered that the illustrious Newton first communicated to the learned world that a ray of Light, incident obliquely onto the surface of a denser transparent medium, is scattered after refraction as if into several rays diverging at small angles and infected with colors, and indeed by such a law that if the sine of the common angle of incidence is set at 44 parts, the sine of refraction of the red ray, which is refracted the least of all, is 68 of the same parts, but the sine of refraction of the violet ray, which suffers the greatest refraction, is 69 parts. From which it is easy to conclude that if a ray LB is dispersed by means of refraction into the red color at BD, and into the violet color at BE, then ND will be to DB (or to DC) as 68 to 44, and likewise NE to...