/ ON THK HISTORY OP MECHANICS. 243 



vancement of theoretical investigation. Hero was of the same school, and his pur- 

 suits were similar ; some of his treatises on hydraulics, pneumatics, and mechanics, 

 are published in the collection of Ancient mathematicians, and some others are 

 still extant in manuscript. We are informed by Pappus, that Hero and Philo 

 liad referred the properties of the lever, the wheel and axis, the pulley, the 

 wedge, and the screw, to the same fundamental principle ; so that (he theory 

 of the mechanical powers began at that time to be extremely well understood. 

 The treatises of Hero on pneumatics and on automatons contain many very 

 ingenious inventions, but they are rather calculated for amusement than for 

 utility; among them is a cupping instrument, which operates nearly in the 

 manner of an air pump. A work of Bito, on warlike machinery, addressed 

 to king Attains, is included in the same collection. 



Vitruvius was an author of great general knowledge: he lived under one of 

 the earliest of the Caesars, and the greatest part of our information respecting 

 the mechanics of antiquity has been derived from his works. ApoUodorus was 

 employed by Trajan, in building a bridge over the Danube, in the year 102; 

 he has left a treatise on besieging a town, which is to be found among the 

 Ancient mathematicians. Diophantus, Pappus, and Proclus, were mathematicians 

 of eminence; Diophantus confined himself in great measure to arithmetic 

 and pure geometry ; but the last book of Pappus's collections is devoted 

 to mechanics, and Proclus wrote a treatise on motion, which is stilj extant. 

 The rudiments of algebraical notation and calculation may be found in the work* 

 of Diophantus ; but the Arabians appear to have first practised the method of 

 denoting quantities in general by literal characters ; they made, however, no 

 considerable advances, and mathematics in general remained nearly stationary 

 until the time of the revival of letters. 



During the long interval, in which learning and science were involved in 

 the darkness of the middle ages, the arts subservient to the convenience of 

 life were also in great measure neglected. It is evident from many remains 

 of antiquity, that various manufactures had attained, in Greece and at Rome,a 

 high degree of perfection; but the irruptions of the barbarians were as effectual 

 in suppressing the refinements of civilisation, as in checking the pursuit of li- 

 terary acquirements: our own country was not the earliest in recovering the 

 arts which had been lost, but it has always received with open arms those 



