that on the surface of the glass itself there also are only vortexes with very little air, but with many of the gross parts of which the glass is composed, and (d) that a ray of light obliquely intersects these two rows of matter with unequal vortexes, and hence with unequal force; it is evident that upon passing from the air to the glass the ray will be diverted toward the perpendicular to these two rows or surface of unequal force, and this will occur in direct proportion to the obliqueness of its intersection of the line.