ARCHITECTURE AND MECHANICAL SCIENCES. 4? 1 



mals out of ivory, which were so extremely small, that their com. 

 ponent parts were scarcely to be distinguished. He says also in 

 the same place, that one of those artists wrote a distitch in golden 

 letters, which he enclosed in the rind of a grain of corn. 



It is natural here to enquire, whether in such undertakings as our 

 best artists cannot accomplish without the assistance of microscopes, 

 the ancients had no such aid ; and the result of this research will be 

 (hat they had several ways of helping the sight, of strengthening it, 

 and of magnifying small objects. Jamblichus says of Pythagoras, 

 that he applied himself to find out instruments as efficacious to aid 

 the hearing, as a ruler, or a square, or even optic glasses, $iOTrrpz 9 

 were to the sight. Plutarch speaks of mathematical instruments 

 which Archimedes made use of, to manifest to the eye the large, 

 ness of the sun j which may be meant of Telescopes. Aulus Gel. 

 lius having spoken of mirrors that multiplied objects, makes men. 

 tion of those which inverted them ; and these of course, must be 

 concave or convex glasses. Pliny says, that in his time, artificers* 

 made use of emeralds to assist their sight, in works that require a 

 nice eye ; and to prevent us from thinking that it was on account 

 of its green colour only that he had recourse to it, he adds, that 

 they were made concave, the better to collect the visual rays ; and 

 that Nero made use of them in viewing the combats of the Gladia- 

 tors. In short, Seneca is very full and clear upuii this head, when 

 he says, that the smallest characters in writing, even such as almost 

 intir?ly escape the naked eye, may easily be brought to view by 

 means of a little glass ball, filled with water, which had all the 

 effect of a microscope, in rendering them large and clear ; and 

 indeed this was the very sort of microscope that Mr. Gray made 

 use of in his observations. To all this add the burning glasses 

 made mention of before, which were in reality magnifying glasses; 

 nor could this property of them remain unobserved. 



[Dtttent. 



SECTION n. 



Comparative View of the Architecture of different Ages. 



THAT architecture is of great antiquity is undeniable. But 

 the primitive buildings were very different from the specimens of 

 architecture we now meet with in civilized countries. Jn those 

 mild climates which seem to have been the first inhabited parts of 



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