A 'LENS' FROM SARGON'S PALACE 119 



of spectacles dates back 'twenty years,' which would be about 1285. 

 It is now known that they were invented by Salvino d'Armato degli 

 Armati, a Florentine, who died in 1317. He kept the secret for 

 profit, but it was discovered and published before his death. But 

 there is a singular evidence that a lens used for the purpose of 

 magnification was in existence as early as between 1513 and 1520, 

 for at that time Raphael painted a portrait of Pope Leo X. which 

 is in the Palazzo Pitti, Florence. In this picture the Pope is drawn 

 holding a hand magnifier, evidently ^intended to examine carefully 

 the pages of a book open before him. But no instruments com- 

 parable to the modern telescope and microscope arose earlier than 

 the beginning of the seventeenth century and the closing years of 

 the sixteenth century respectively. 



It is, of course, known that there is in the British Museum a 

 remarkable piece of rock crystal, which is oval in shape and ground 

 to a plano-convex form, w r hich was found by Mr. Layard during the 

 excavations of Sargon's Palace at k 



Ximroud, and which Sir David 

 Brewster believed w 7 as a lens de- 

 signed for the purpose of magni- 

 fying. If this could be established 

 it would of course be of great 

 interest, for it has been found 

 possible to fix the date of its pro- 

 duction with great probability as 

 not later than 721-705 B.C. 



A drawing of this * lens ' in two 

 aspects is shown in figs. 88 and 89, 

 and we spent some hours in the 

 careful examination of this piece 

 of worked rock crystal, which by 

 the courtesy of the officials we were 

 permitted to photograph in various FIG. 89. An Assyrian ' lens ' (?). 

 positions, and we are convinced 



that its lenticular character as a dioptric instrument cannot be made 

 out. There are cloudy striae in it, which would prove fatal for 

 optical purposes, but would be even sought for if it had been intended 

 as a decorative boss ; while the grinding of the ' convex ' surface 

 is not smooth, but produced by a large number of irregular facets, 

 making the curvature quite unfit for optical purposes. In truth, 

 it may be fairly taken as established that there is no evidence of any 

 kind to justify us in believing that lenses for optical purposes were 

 know T n or used before the invention of spectacles. 



From the simple spectacle-lens, the transition to lenses of shorter 

 and shorter focus, and ultimately to the combination of lenses into 

 a compound form, would be in such an age as that in which the 

 invention of spectacles arose only a matter of time. But it is 

 almost impossible to fix the exact date of the production of the first 

 microscope, as distinguished from a mere magnifying lens. 



There is nevertheless a consent on the part of those best able 

 to judge that it must have been between 1590 and 1609 ; while it is 



