On eye-pieces for telescopes and microscopes / [Cornelius Varley].

  • Varley, Cornelius, 1781-1873
Date:
[1835?]
Catalogue details

Licence: Public Domain Mark

Credit: On eye-pieces for telescopes and microscopes / [Cornelius Varley]. Source: Wellcome Collection.

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    *:iz:cT j ON EYE-PIECES FOR TELESCOPES AND MICROSCOPES. By Mr. CORNELIUS VARLEY. FROM THE TRANSACTIONS OF THE SOCIETY OF ARTS, MANUFACTURES, COMMERCE, &c. VOL. LI. When I invented the graphic telescope (described in Vol. L. of the Society’s Transactions), the chief obstacle was in the eye-piece; the usual achromatic eye-pieces shewing the image beautifully distinct, but with all the lateral lines so curved as to become useless for any pur¬ pose of art : and, as perfect truth of form in every part of the image is the chief requisite for a drawing instru¬ ment, I was obliged to give up the perfect correction of colour to obtain truth of form ; but as low powers are the most useful in drawing from nature, the loss from imper¬ fect correction is not so much felt as I at first feared. Although the compound microscope, as well as the astronomical telescope, requires truth of form along with the most accurately defining power, these two qualities have not, to the present time, been well reconciled, so as to be found in the same eye-piece. Yet there are resources in optical science which, I believe, are fully able to effect this union in the most satisfactory manner. I therefore propose giving a full view of the three principal eye-pieces : namely, the achromatic, which is B