ON TIIE HISTORY OP MECHANICS.

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vancement of theoretical investigation. Hero was of the same school, and his pur-suits were similar; some of his treatises on hydraulics, pneumatics, ami mechanics,are published in the collection of Ancient mathematicians, and some others arestill extant in manuscript. We are informed by Pappus, that Hero and Philohad referred the properties of the lever, the wheel and axis, the pulley, thewedge, and the screw, to the same fundamental principle; so that the theoryof the mechanical powers began at that time to be extremely well understood.The treatises of Hero on pneumatics and on automatons contain many veryingenious inventions, but they are rather calculated for amusement than forutility; among them is a cupping instrument, which operates nearly in theWanner of an air pump. A work of Bito, on warlike machinciy, addressed^ king Attalus, is included in the same collection.

Vitruvius was an author of great general knowledge: he lived under one ofthe earliest of the Caesars, and the greatest part of our information respectingthe mechanics of antiquity has been derived from his works. Apollodorus was^ployed by Trajan , in building a bridge over the Danube , in the year 102;le has left a treatise on besieging a town, which is to be found among the■^Ucient mathematicians. Diophantus , Pappus, and Proclus , were mathematicians°f eminence; Diophantus confined himself in great measure to arithmeticai *d p ure geometry; but the last book of Pappus’s collections is devotedt® mechanics, and Proclus wrote a treatise on motion, which is still extant.le rudiments of algebraical notation and calculation maybe found in the worksDiophantus ; but the Arabians appear to have first practised the method ofNoting quantities in general by literal characters; they made, however, noc °Usiderable advances, and mathematics in general remained nearly stationary^til the time of the revival of letters.

• i vh learning and science were involved inDuring the long interval, m w « . subs ervient to the convenience of

he darkness of the middle ages, ^ evident f rom many remains

he were also in great measure neglec had attained,in Greece and at Home,a

? f antiquity, that various manufactu barbarians were as effectual

Nhdcgree of perfection; checking the pursuit of li-

suppressing the refinements of c ^ ^ in reC0V e V ing the

Crary acquirements: our own coun y received w j t h open arms those

arts which had been lost, but it has alw )