Instruments of the Ant tents. I9 



the trouble of referring to other works, to satisfy himself 

 that the art of making and variously mouldino- tran.^parent 

 glass, was practised in England above 500 years before the 

 time of Roger Bacon; and consequently that he coidd be 

 at no loss to procure that material for his experiments. But 

 these remote historical facts must here give place to others, 

 more immediately connected with the present inquiry. In 

 "John Dee his Mathematicall Preface to Euclid^ IFrit- 

 ten," to use his own words, " at my poor house at Mort- 

 lake, anno isro, Febr. Q," I find the following curious, 

 but long neglected, passages; which, had I known of them, 

 should have been inserted before I arrived at this miscella- 

 neous conclusion of my conmiunicalions. I must observe, 

 that the copy of Dee's '' very curious and elaborate" p"re- 

 face, in 95 small 4to pages, now before me, is prefixed, 

 not to his own edition of the Elements, which " was pub-" 

 lished by Henri/ BilUngsley in 1570*, but to "Euclid's Ele- 

 ments of Geometry, the first VI books, in a compendious 

 form contracted and demonstrated, by Capt. Thomas Rudd, 

 Chiefe Engineer to His late Majesty; whereunto is added 

 the Mathematicall Preface of Mr. John Dee ; London : 

 Printed by R. and W. Leyboura, R. Tondins and R. Boy- 

 del], 1651." This date will account fof the orthography 

 and punctuation, which I copy, being more modern than 

 that which was fashionable, in 1570, when this interestino- 

 preface was first printed. 



18. Dee defines " Perspective'" to be " an Art Mathe- 

 maticall, which demonstrateth the nature and properties of 

 all Radiations, Direct, Broken, and Reflected." And 

 ** Glasse," according to him, " is a gcnerall name, in 

 Catoptrifie, for any thing from which a Beam rehoundcth." 

 — " Is it not greatly," he asks, " against the Soveraitrnty 

 of Man's nature, to be so overshot and abused with thlnir? 

 (at hand) before his eyes ? as with a Peacock's tail, and'a 

 Dove's neck : or a whole ore, in water holden, to seem 

 broken. Things far oiT to seem necr, and neer, to seem 

 |ar off. Small things to seem great, and great to seem 

 ^mall. One man to seem an Army. Or a man to becurstly 

 afraid of his own shadow. Yea, so nuich, to fear, that if 

 you being a lone, neer a certain glasse, and profler with 

 dagger or sword, to foyne at the glasse, you shall suddenly 

 be moved to give back (in manner) by reason of an Image 

 appearing in the air, between you and the glasse, with like 

 hjjinl, sword or dagger, and with like quicknesse foyning 



• Ste Dr. ILilvi't Diryonarv, art'C.'e Drf 



