( 225 ) 



*' adjuft it to the eye of the beholder. Several writers reprefent the glafles 

 " Mr. Leeuwenhoek made ufe' of in his Microfcopes to be Tittle globules, 

 " or fpheres of glafs ; which miftake moll probably arifes from their under- 

 " taking to defcribe what they had never feen ; for, at the time I am writing 

 " this, the cabinet of Microfcopes left by that famous man, at his death, to 

 " the Royal Society as a Legacy is (landing upon my table; and I can alTure 

 " the world that every one of the twenty-fix Microfcopes, contained thereiuj 

 " is a double convex lens, and not a fphere or globule." 



And in another treatife, publifhed by Mr. Baker fome years afterwards, 

 he writes as follows : * 



" An accurate defcription of the twenty-fix Microfcopes, and objects be- 

 " longing to them, contained in a fmall cabinet, which Mr. Leeuwenhoek* 

 " at his deeeafe, bequeathed to the Royal Society, was prefented many years 

 " ago to that Society by Martin Folkes, Efq. and may be feen No. 380 of 

 " the Philofophical Tranfaflions. And a farther account, fetting forth the 

 " magnifying powers and other particulars concernmg the faid Microfcopes 

 " (which were three months under my examination for that purpofe), was 

 " prefented by me to the Royal Society in the year 1740, and publifhed in 

 •' Phil, Tranf. No. 458. But neither of thefe accounts has any drawing of the 

 " Microfcopes : it is therefore hoped the curious will be pleafed to fee a draw- 

 " ing of them, taken, with great exaftnefs, from thofe in the Repofitory of 

 *' the Royal Society, which are all alike in form, and differ very little in fize 

 " from this drawing, or from one another. 



" The two fides of one of thefe Microfcopes are fhewn at^^. 18 and IQ: 

 " the eye mud he applied to the fide Jig. 18. The liat part. A, is compofed 

 " of two thin filver plates, faftened together by little rivets b, b, b, b, b, b. 

 " Between thefe plates a very fmall double convex glafs (called by mathema • 

 *' ticians a lens) is let into a focket, and a hole drilled in each plate, for the 

 " eye to look through, at c. A limb of filver, d, is faflened to the plates 

 " on this fide by a fcrew, e, which goes through them both. Another 

 " part of this limb, joined to it at right angles, paiTes under the plates, and 

 " comes out on the other fide (fee^°-. ig) at f ; through this runs, dircQly 

 " upwards, a long fine-threaded fcrew, g, v.hich turns in, and raises or lowers 

 " the flage, h, whereon a coarfe rugged pin, i, for the objeft to be fallened to, 

 ♦' is turned about by a little handle, k, and this ilagc, with the pin upon it, 



• Employment for the Microfcopc, p. 13J. £d. 17G4. 



Vol. II. F t^ 



