Microscopium polydynamicum : or, a new construction of a microscope, wherein a variety of magnifying powers is communicated to each object-lens / [Benjamin Martin].

  • Benjamin Martin
Date:
1771
Catalogue details

Licence: Public Domain Mark

Credit: Microscopium polydynamicum : or, a new construction of a microscope, wherein a variety of magnifying powers is communicated to each object-lens / [Benjamin Martin]. Source: Wellcome Collection.

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    However I find by Experience with three feveral Achro~ maficLenfes of different focal Lengths, that the Image will not bear to be encreafed beyond 5 or 6 times, for after that, it becomes indiftinct, as in Common Microfcopes. And for great Powers of Magnifying exceeding fmall Ob- je£ts, as the Particles of Blood, See, we muft be content with our Common Lenfes, which do extremely well in¬ deed, and I very much queflion if they will ever be equalled by any achromatic Microfcopic Lenfes of fhort focal DiftanceSj that may hereafter be made. It would be well worth any Gentleman’s while, who has got one of the Patent or Achromatic Operas, to have it converted into a Microfcope of the Sort now deferibed; for the inftrument being ferewedupon the Lid of the Box (which contains it) will ftand On the Floor* and the up¬ per part will reach the Eye as you fit in a Chair, and give an Opportunity of viewing Obje&s with the utmoft Eafe and Conveniency. I think no one can now doubt, that*one and the fame Lens F will (hew every Object in Nature as far as a Power of Magnifying 50 times will go; If any Scruple fhould remain concerning fuch univerfallity in the Ufe of One Lens only, it is in any Perfon’s Power to have them re¬ moved by Experiment whenever they pleafe; fo nothing more needs be faid upon that Head. It will require but few Words to obferve (in Conclu- fion of this Subjedt) That as the Images at G, H, I, K, Scc. are as 1, 2, 3, 4, Scc. fo the Diftances ED, EC, EB, EA, will be -J, 4, t of the Line AE; and con- fequently the faid Line AE will be divided in Harmoni- cal Proportion in the Points B, C, D, See. or Places of the Objedt, for producing Images in Arithmetical Progref* fiort, as arethofe in the Figure. FINIS.
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