ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 583 



discovery of spectacles, or as it may be called, of the simple Microscope, 

 may be equally divided between lloger Bacon and Salvino degli Armati, 

 leaving especially to the latter the invention of spectacles. 



The first lenses for spectacles were it seems made from rock crystal 

 and beryl, and either because they believed those made of glass hurtful 

 to the sight, or void of any virtue, or in order to prevent the fraud of 

 giving glass for crystal, Venice, in April 1300,(27) strictly prohibited 

 glaziers selling, as if made of crystal, the rotelle da occhi (roidi da ogli), 

 round shields for the eyes, and le pietre da leggere (lapides ad legend um), 

 reading-stones. 



But a year later, 15th June, 1301, the old Giustizieri who superin- 

 tended the arts, allowed every one to make Vitreos ah oculis ad legendum, 

 on condition that they should be sold as glass and not as crystal ; and in 

 March 1317, they granted the privilege of making oglarios de vitro, and 

 to sell them in Venice in spite of the chapter of the guild of crystal- 

 makers. 



The first lenses having been cut in beryl or in rock crystal, led 

 them to be indifferently called Berilli, as in those days very different 

 gems were confused under the same name, and in Germany the word 

 Brillen has remained for all lenses, whilst the French for the same 

 reason first called spectacles Bericles, and then Besides (by corruption), 

 which the Piedmoutese in their dialect used to call and still call 

 Buricole. Nicolo Krebs, from Cuss, better known under the name of 

 Nicolo Cusano, who lived from 1401 to 1464, called one of his writings 

 Berillo, because, thanks to its help, things otherwise incomprehen- 

 sible could be understood, and in the second chapter of this book he 

 says (28) : — 



" The beryl is a resplendent, colourless, and transparent stone, to 

 which is given a concave or convex form, and those who look through it 

 succeed in discovering things at first invisible." 



De la Borde (29) quotes a passage of a certain writing of the 

 sixteenth century, in which the cost is mentioned : " Pour dix paires de 

 lunettes apportees a deux fois audit Seigneur Eoy audit lieu de Bar, 

 dont y en avoit trois paires de cristal et lesautres deberil." (" For ten 

 pairs of spectacles brought at two different times to the said Lord the 

 King, at the said place of Bar, of which three were crystal and the others 

 beryl.") 



This shows that in those days they continued making lenses of 

 crystal and beryl for those gentlemen who could afford them. Little by 

 little, however, the use of beryl lenses disappeared, and even rock- 

 crystal ones have become rarer, although they are still made especially 

 to prevent their being scratched or dulled too soon by use. 



But if from the time of Eoger Bacon it was known that convex 

 lenses enlarged the images of objects, (30) so that one could obtain en- 

 largements of objects from five to ten times, and therefore one could with 

 them see small objects sufl&ciently enlarged, yet no advantage for the 

 knowledge and study of nature could be derived from them. One pos- 

 sessed the simple Microscope, but the observers and the observations 

 were wanting. 



Girolamo Fracastoro, in his book on ' Omocentrici,' published in 1538 

 (chapter vii.), says that, " Per duo specilla ocularia si quis perspiciat, 

 altero alteri superposito, maiora multo, et propinquiora videbit omnia." 

 And a little further on, chapter xxiii., " Quinimo qusedam specilla 



