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doe, if setled in these Tubes; having no need of them, I rest as I am. Now I should be heartily glad, if any of my friends should receive any aid or ease by such an obvious device (containing nothing but emptiness and darkness) as this is. And probably they may be more proper for some that are Squint-eyed, whose eyes doe interfere, and so make the object, as if you would write one line upon another, where, though both should be ever so fairly written, yet neither will be easily legible. Here Squint-eyes will be kept in peace, and at fair Law. Certainly it will ease them, that cannot well bear the light; and perchance it will preserve the sight for longer durance. If N. N. should find the benefit, as I do, he may thank you for the information, &c.
An Extract
THere is more worth in that slight notice, which I sent you last, than any one, that hath not the defect, which I have, will easily imagine. And perhaps no man will have the patience to endure to use it, but he, that is in a like case of necessity and distress as I am. I praise God for it, I see now by this trifle (these Taper-tubes) as well as the youngest in my Family, and can read through them the smallest and blindest Prints, as ever I could from my childhood, though my sight be almost lost. And having used these empty holes for Spectacles little more than a week, I can now use them without trouble all the day long; and I verily believe, that by this little use of them, my sight already is much amended. For I do now see the Greeness of the Garden, and Pastures in a florid verdure, whereas very lately dark colours, blue, and green, had the same hue to my eye.
If you ask me, how this device came in my head, I shall tell you all I do know. Some years agoe I was framing one of Hevelius's Polemoscopes: As I was trying the Tube, without the Dioptrick Glasses, I perceived, that, though the Tube took in very little, and seem'd scarce serviceable for any considerable purpose; yet the object appear'd to me more distinct and clear through the Tube, than through the open Air. This I recollected,
