A Substitute for Spectacles.

Otago Witness, Issue 2541, 26 November 1902, Page 64

A Substitute for Spectacles.

When ape arrives, the ;rystalline lens fails, and one becomes far-sighted ; th© objectionable spectacles are necessary, and if the infirmitj is advanced, the slightest reading, the most trifling use of the eyes, is impossible without the assistance of glasses. Frequently these are not at hand, and the resulting annoyance may be remedied in a great measure (says "Cosmos") in the following way : —

When a photograph ic object-glass is defective, the trouble i« corrected and great clearness is given to the 'mage by employing a diaphiagm with a narrow opening, which utilises only a small surface of the lens. As the far-sighted human eye is nothing more than a defective lens, a French scientist decided to apply to it this principle, constructing a pair of spectacles in ■which the glasses are replaced by two small plaites of metal pierced \\ ith a hole one-half millimetre in diameter, by which, he states, ordinary s-pectacles are perfectly replaced.

We suppose the remark will immediately be made that it is as easy to carry a regular pair of spectacles as this new instrument; but this is not go, for the apparatus is easily made by piercing a visiting card with two small holes, using for this purpose an ordinary pin. The only requisite in making the instrument is to place these holes at a convenient distance, that is, in puch a way as to make the visual rays of the two ejr«s converge on &• isttf object »t the

distance at which it is desired to reocL If this precaution is not taken, only one eye is used in looking through the card. With this instrument one also has the luxury of reading as a short-sighted person reads, with the book held a comfortable distance from, the eye.