THE MIDDLE AGES AND DURING THE REVIVAL. 51 



claws and flames, to deliver their fellow-men from unspeak- 

 able evils. Bearing this in our minds, the progress of the 

 later Middle Ages and the Revival has been absolutely 

 marvellous. 



Those times witnessed : 



I. most VALUABLE INVENTIONS ; 



II. the appearance of some of the most important AGENTS 

 OF PROGRESS humanity can boast of ; 



III. the discovery of scientific LAWS of the highest order. 

 Here again we have to be satisfied with brief records. 



During this era there came into existence : 



IXth c.* Watermills. The Romans were in possession of 

 them in an imperfect form as early as 500 A.D. 



IXth c. The Organ, an orchestra in itself, the sublime 

 instrument par excellence. It gradually grew out of a hand 

 and bellows pipe known among the Romans. Nero had an 

 organ worked by water. 



IXth to XlVth c. Clocks were improved in diverse ways, 

 -especially after Henry de Wyck (1364). Needless to speak 

 of the Hour-Glass, of which there was a variety. 



Xth to Xllth. Music the creation of a new language 

 (musical notation and harmony) of which Hucbald (d. 930), 

 Guido d'Arezzo (1024), and Franco (1050-1083) were the 

 chief pioneers a gradual progress in the " use of the 

 phenomena of sound " until the XVIth century, accompanied 

 by the invention of various instruments (harpsichords and 

 clavichords). Bishop Ambrosius of Milan (340 397) and 

 Pope Gregory I. (544604) were associated with the earlier 

 .advance of Music. About 1400-20 DUNSTABLE invented 

 polyphony. 



Xlth, Xllth. Windmills, whether invented in Europe or 

 introduced from the East during the Crusades, spread rapidly 

 during the Xllth century. 



1115 1302. The Compass, which effected a fourfold 

 revolution revolution in theology, astronomy, geography, 

 commerce. The CHINESE (see Klaproth) were possessed of 

 it. They used it on land in the absence of roads as early as 

 the Xllth century before our era. From the Vllth to the 

 * All these dates are approximate only. 



2 



