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

  • Martin, Benjamin, 1705-1782
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.

    15/18 (page 9)
    Concaves, and therefore with fo many different Magnify¬ ing Powers for (hewing diftant Obje£ta as a Telefcope; and that, by the greateft Magnifier, Jupiter's Moons may be feen. Now the very fame Achromatic Lensy if applied in the preceeding Conftru&ion, will become the Objecff-Lens of an Achromatic and Polydynamic Microfcope; and which will magnify in every degree from 8 to 40 or 50 times, as will be evident by contemplating Fig. 2. where F is the Achro- matic Lens; its focal Diftance FE; and A, B, C, D, fuch Pofitions of the Objea below it, as will make the Images G, H, I, K, above it, in proportion to the Ob¬ jea, as the numbers 1, 2, 3, 4, See, to 1. Hence fince the Image at G, is 1, or equal to the ob- jea, it is at the fame Difiance from the Lens, or FGn: FA1Z2FE; and the Magnifying Power is now only by the Eye-Glafs, fuppofe 8 times. The Image at H being as 2, or twice as big as the Ob¬ jea now at B, will double the Magnifying Power, or make it 16 times. In like manner the Image I being 3, times as large as the Objea at C, will produce a Power of Magnifying 24 times ; and the Image at K, 4 times as long as the Objea, will caufe a Magnifying Power of 32 times, and thus you may proceed for a Power of magnifying 4© or 50, and, in fome Cafes, even to 60 times. But a Power of Magnifying 40 times will be found full fufficient to give a moft delightful View of all fmall Ob- jeas in General, as the Aperture here exceeds that of a Common Microfcope as much as it does a common Te¬ lefcope when ufed as fuch ; being from 3 to 6 Tenths of an Inch in that Lens which (hews Jupiter’s Moons. And therefore the Quantity of Light is very great, and tenders the View of all Objeas, equally agreeable and pleafantv How-