Micrographia illustrata, or, the knowledge of the microscope explain'd: together with an account of a new invented universal, single or double microscope, either of which is capable of being applied to an improv'd solar apparatus ... ; To which is added, a translation of Mr. Joblott's observations on the animalcula, that are found in many different sorts of infusions; and a very particular account of that surprising phænomenon, the fresh water polype, translated from the French treatise of Mr. Trembley ... / By George Adams.

George Sr. Adams

Date:: 1747

Credit: Micrographia illustrata, or, the knowledge of the microscope explain'd: together with an account of a new invented universal, single or double microscope, either of which is capable of being applied to an improv'd solar apparatus ... ; To which is added, a translation of Mr. Joblott's observations on the animalcula, that are found in many different sorts of infusions; and a very particular account of that surprising phænomenon, the fresh water polype, translated from the French treatise of Mr. Trembley ... / By George Adams. Source: Wellcome Collection.

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form of a Lattice ; in fuch a Manner, that the Diftances between the Wires are exadjy equal to the Diameter of the Wire itfelf. By which Means having a Wire, whofe Diameter is a certain known Part of an Inch, we may be able to meafure a very fmall Animalcule, &c. and be more exad in our Calculations, than by either of the former Methods. For by placing this Lattice of Wires, dole under a Mufcovy Talc, upon which the Oojedt may be placed, if it be tranfparent, or placing the Lattice over the Objed, ii it be an opake one. And when the Objed is adjufted to the Mao-nifier,5 the Parts thereof may be eafily compar’d with the Number of Wires and Intervals, and their true Magnitude, or Dimenfions very nearly known, or if I obferve the Diameter of an Objed to be juft the fame with one Wire, or an Interval, I know it is the 560th Part of an Inch, fuppofing the Wire of that Size. If half that Width, the 1120th Part of an Inch; if one Quarter of the Width, the 2240th Part of an Inch, and fo on ad infinitum. Or thus, if an Objed cover but the 6th Part of the Diameter of a Wire or Hterval, it Wi^ be but 3360th Part of an Inch in Diameter, which multiplied into itfelf, will fhew the Superficies to be the 11,289,600th Part of an Inch, and that Produd multiplied by the firft Number will fhew the Solidity to be the 37933,056,000th Part of an Inch, and thus may the Minuteneis of any Objed be exadly determined. . however, this laft Method, tho’ infinitely better than any other in Prac- tice amongft us, is ftill deficient an this Account ; if the Objed be confi- Iiclerabiy lefts than the Diameter of one fingle Wire or Interval between the Wires, we are obliged to eftimate, or guefs its Proportion to that Dia¬ meter or Interval; but if the Objed be no fmaller than one fourth Part of me 1 Interval, the Eye is able to determine that to the utmoft Exadnefs pollible. J ^h^fore, to remove this Deficiency, invented a particular and i°us ic ro me ter, applicable both to fingle and double Microfcopes, antl Part!Cular]y adapted to my Univerfal Microficope, deferibed Fig i, koninw y°wer of the folar Microfcope, is found by rec- Ixtvlefn °rW 77 I'T the. f°cal Diftance of the Magnifier is contain’d of a i O if<>n - % * i-lnC> °[ t^ie ’creen> or Sheet, upon which the Image U fe t jLL t a ' T ,01 n:ance’ let us hippo Te the Focus of the Lens in and'as tlftf * ? ft1 7, a' ,<' t^le Screen fet at the Diftance of fix Feet, Screen’s l)d^W|8thn° the Lens will be contained 2B8 times in the tion of dq.P“of an Objed is magnified in the Proper- Bulk 2? 88- * '?T'ftc‘es 8z’944 times, and its Solidity, or jtet may bcmlnifiT’ ^ 7 re?oving the Screen farther off, the Ob- ’ y Dc magnified to almoft what Size you pleafe. CHAP.

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