Physiologia Epicuro-Gassendo-Charltoniana, or, A fabrick of science natural, upon the hypothesis of atoms founded by Epicurus repaired [by] Petrus Gassendus ; augmented [by] Walter Charleton ...

CONSECTARY the First.

* 1.1Now, it being no less Evident, then Certain, that the Image is the sole cause of the Objects apparence under such or such a determinate Colour, and of this or that determinate Figure: it is of pure Consequence, that the Image must also be the Cause of the Objects appearance in this or that de∣terminate Magnitude; especially since Figure is essenced in the Termina∣tion of Magnitude, according to Euclid. (lib. 1. def. 14.) Figura est, quae sub ali∣quo, vel aliquibus terminis comprehenditur. For, why doth the object ap∣pear to be of great, small, or mean dimensions; if not because the Image arriving at the sentient, is great, small, or mean? Why doth the whole ob∣ject appear greater then a part of it self; unless because the whole Image is greater then a part of it self? To speak more profoundly, and as men not altogether ignorant of the Mysteries in Opticks; demonstrable it is, that the Magnitude of a thing speculated may be commensurated by the propor∣tion of the Image deradiated from it, to the distance of the Common Inter∣section. For as the Diametre of the Image, projected through a perspe∣ctive, or Astronomical Tube, on a sheet of white paper, is in proportion to the Axis of the Pyramid Eversed; so is the diameter of the basis of the Object to the Axis of the Pyramid Direct. And hereby also come we to apprehend the Distance of the Object from the Eye; for having obtained the Latitude of the object, we cannot want the knowledge of its Distance: and by conversion, the knowledge of its distance both assists and facilitates the comprehension of its Magnitude. Which comes not much short of absolute necessity; since as Des Cartes (Dioptrices cap. 6.) hath excellently observed, in these words: Quoniam autem longitudo longius decurrentiam radiorum non exquisite salis ex modo impulsus cognosci potest, praecedens Di∣stantiae scientia hic in auxilium est vocanda. Sic, ex Gr. s•• distantia cognos∣catur esse magna, & Angulus visionis sit parvus; res objecta longius distans judicatur magna: sin verò distantia sciatur esse parva, & angulus Visionis sit magnus; objectum judicatur esse parvum, si verò distantia objecti longi∣us dissiti sit in cognita; nihilcerti de ejus magnitudine decerni potest: if the Distance of an object far removed be unknown, the judgment con∣cerning the magnitude thereof must be uncertain.

Notes

• * 1.1

  Art. 10. CONSECTA∣RY.

  That the I∣mage is the Cause of Ob∣jects apparence of this or that determinate Magnitude.