eyeglasses

Eyeglasses were being made over a century earlier: The earliest recorded working telescopes were the refracting telescopes that appeared in the Netherlands in 1608. Their development is credited to three individuals: Hans Lippershey and Zacharias Janssen, who were spectacle makers in...

No, not drinking glasses. This will be difficult to test, but if you're a spectacles wearer and you see a ghost, would that ghost be blurry without the glasses but clear with them? What I mean is, it would be a good test of whether there is something in the room with you to see if the...