very near also; whereby the Eye is dazl'd and confounded, unless there be a strong attention and conatus of the Spirits, whereto the bright Rays do certainly engage them, which of necessity weakens Vision, especially if these Glass-spectacles be much us'd.
Wherefore the now describ'd new Tube-spectacles, contributing so much to the help and preservation of Sight, may well be counted an improvement of Direct Vision, because they convey the Rays to the Eye without any kind of Refraction whatsoever. Seeing the same Object also through various holes, plac'd at certain distances, does somewhat alter Vision; but of this perhaps more hereafter.
Now as Direct Vision has thus been improved, so likewise Direct Hearing partly has already receiv'd, and partly may by the Doctrine
whereof we are treating, (if well cultivated) farther receive as great and notable Improvements, both ex parte Objecti, and ex parte Organi vel Medii.
- As to the Object of Hearing, which is Sound, improvement has been and may be made, both as to the Begetting,