

OF GLASSES FOR OPTICAL PURPOSES 35 



But onely the quality of the eye ys to see, and 

 begynneth at a poynte, withoute any quantity or 

 bignes. As for example you may knowe yt by 

 this : Pricke a hoale in any thinge, with the poynte 

 of a fine needle, and then holde that vnto your 

 Eye, and beholde any thinge thorowe the hole, 

 and you may see a greater thinge, if that yt bee 

 any distance from yow : yow may beholde a 

 whole towne, beeynge a greate distance from 

 you, &c. And for that perspective ys the dis- 

 cerning of any thinge either substancyall or acci- 

 dentall, accordinge to the bignes, and distance, and 

 hath his boundes, betweene too righte lynes, from 

 a poynte : And so extending infinitely from the 

 sight of the Eye, yt showeth y t self according to 

 the quantity or bignes, correspondent vnto the 

 distance. And for that perspective ys muche 

 amplifyed and furdered by the vertue and meanes 

 of Glasses, I do thinke yt good to shewe the pro- 

 perty of glasses : And suche, as touchinge the 

 nature and quality of glasses, commonly called 

 Lookinge Glasses. Whiche are those sortes of 

 Glasses, that have a ffoyle, layde on the backe syde 

 thereof, that causeth the same glasse to cast from 

 yt a beame or shadowe, accordinge vnto the 

 forme of that thinge that standeth ageanst yt 

 shewynge y t vnto the sighte of the eye. Whereof 

 there ys three severall sortes, accordinge vnto 

 the sundry makinge and polisshinge of these 

 glasses : I do not meane sondry sortes of stuffe, 

 ffor that theare ys some sortes of lookinge glasses 



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