No. VI. Curious Experiment

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VII. Dr. WELLS on the Changes which the
Vision of Short-sighted Persons un-
dergoes from Age.....




VIII. Mr. WARE'S Observations on the Near
and Distant Sight of different Persons 235

IX. Appendix to Mr. WARE's Paper, by


X. Sir WILLIAM HERSCHEL on the Aper-
tures of the Pupil of the Eye



XI. Snow Spectacles...


Explanation of the Plate fronting the Title.

FIG. I. Is the Spectacle front recommended for Eyes in general; the distance between the centres of the openings which hold the Glasses being 2 inches, i. e. the average distance between the centres of the Eyes.

FIG. II. Is a portrait of the Pupil of the Eye when in a state of expansion. See Chapter XII. page 81, and No. X.

of the Appendix.

FIG. III. The Pupil in its most contracted state. page 81, &c.


FIG. IV. Convenient double Folding Hand Spectacles. See page 22.

FIG. V. A PRESERVER, or the First Sight for Long Sighted Eyes, i. e. a Convex lens of 36 inches focus cut in half to shew its form, &c. the thickness of it at the middle and at the margin of it. See page 29.

FIG. VI. The 8th Sight, for Long Sighted Eyes 12 Inches focus.


FIG. VII. No. 1 CONCAVE, or the First Sight for Short Sighted Persons. See Chapter XIII. page 94.

FIG. VIII. No. 12 Concave, or the 12th Sight for Short Sighted Persons.

The Plate of the Pancratic Eye-Tube and Double Stars

to face page 130.



Now, friendly Reader, before I take leave of You-after-Your deliberate perusal of this Volume, if You vote that my labour has been lost, or has afforded you so little pleasure, that You begin to think You would rather have your Seven Shillings in your pocket again, than this first part of "the Economy of the Eyes" under your Chin,-allow me to suggest, that You ought to Lend it to every body You know-to prevent others being decoyed, as in such case You will suppose you have been-to buy a Book which is not worth reading.

But if it so happen that fortunately for the Writer, You think you have derived Amusement or Instruction from his Work,-if You are so good as to wish to be grateful for the Information which it has given you-LEND IT NOT to one of those prudent folks who are in the habit of borrowing your New Books, and so contrive to become wise at your expense,but do the Author the favour to recommend all your Friends to purchase it.


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