426 POPULAR SCIENCE MONTHLY 



Brille (spectacles) is from beryllus, the Latin name of a transparent 

 stone. The French besides also point to beryl. Bericle is an earlier 

 form of beside for ' besiculum,' a little beryl. In some of the French 

 dialects the first syllable ber- is still preserved, bnt the Parisian word 

 for spectacles is besides, in which the original r has been changed to s, 

 according to a phonetic law traceable in other words also. The Span- 

 iards, Italians and Russians have each a native word to designate this 

 article of common use. 



There is a passage in Pliny that is usually cited as evidence that 

 something akin to spectacles must have been in use at least in his 

 time. He relates that the Emperor Nero used a precious stone which 

 he calls ' smaragdus,' generally translated ' emerald/ through which he 

 was accustomed to gaze on the gladiatorial combats; or rather, this is 

 what he seems to say. There is, however, little doubt that Dr. Magnus, 

 the latest author to examine the passage critically, is right in holding 

 that it means no more than that the emperor was in the habit of gazing 

 upon an emerald which he used to carry with him for the purpose of 

 resting his eyes when they became tired looking upon shows that were 

 interesting to him. This view is rendered the more probable from the 

 belief of antiquity that green has a restful effect upon the eyesight. 



Contrivances for bringing the rays of the sun to a focus in order 

 to produce combustion have been employed almost from time im- 

 memorial. A curious proposal bearing on this point is made by 

 Aristophanes in his comedy of the ' Clouds.' Strepsiades, the hero of 

 the play, is greatly harassed with debts and has not the wherewithal to 

 pay. He therefore proposes to his master to get a stone at some 

 chemist's shop of the kind with which they kindle fire, and when the 

 clerk is entering the suit, to stand at some distance and melt it out. 

 As the writing tablets then in use were probably thin boards covered 

 with a still thinner coating of wax on which the writing was done 

 with a pointed instrument, it would not require great heat to effect the 

 purpose. Besides, if, as seems to have been the case and custom, burn- 

 ing-glasses were used to kindle fires, they must have been of consider- 

 able size even in a country like Greece where the sun shines very hot 

 most of the year. Moreover, we are told, they were kept in the 

 chemists' shops for this purpose. If by any mishap the sacred fire 

 watched over by the Vestal Virgins in Rome went out, it was rekindled 

 by means of a burning-glass. Polybius, when speaking of the siege of 

 Syracuse by the Romans, B.C. 214, relates that they were unable to 

 take it from the side of the sea because of the engines employed 

 against them by Archimedes, unquestionably the greatest mechanician 

 of the ancient world. Says he : " So true is it that one man and one 

 intellect properly qualified for the particular undertaking is a host in 

 himself and of wonderful efficacy." The Romans were confident that 

 they could take the city ' if one old man could be got rid of.' He 



