1 66 THE POPULAR SCIENCE MONTHLY 



not participants. Science and art were neglected, and in literature 

 they were largely indebted to the Greeks. Only in building and public 

 works did the practical spirit of the Romans assert itself with any 

 originality. Even here outside assistance was relied upon to furnish 

 the necessary technical skill, the order issued by Augustus Csesar that 

 all the world should be taxed being based on a survey by Egyptian 

 surveyors. 



The fifth century a.d. was known as the " Era of the Great Migra- 

 tion." Owing, it is supposed, to climatic changes, the Teutonic tribes 

 inhabiting the great central plain of Europe were forced outward, and 

 poured east and south into the Eoman empire. So great was the dis- 

 turbance occasioned by this outbreak that nearly two centuries elapsed 

 before the turbulance subsided sufficiently to note the changes that had 

 taken place. Meanwhile an invasion from the east threatened for a 

 time to give an Asiatic cast to civilization. With the fanaticism bred 

 by the inaccessible deserts of the Arabian peninsula, the Saracens in 

 the seventh century swept westward until they reached southern France, 

 where the tide was finally turned by Charles Martel on the field of 

 Tours. No less astonishing than their conquests was the facility with 

 which the Arabs assimilated the culture and learning of the nations 

 whom they subjugated. Their capitol Bagdad, situated on the 

 Euphrates midway between Greece and India, soon became by reason 

 of its location the meeting place for the scientific thought of these 

 nations, whence it was transmitted by their conquests to western 

 Europe. The mathematical attainment of the Arabs was, however, 

 distinct from those of either Greece or India, its trend being deter- 

 mined by their religious observances. Thus the extent of the Moslem 

 dominions coupled with the requirement that a believer should face 

 toward Mecca during prayer, made a determination of direction neces- 

 sary. Also the performance of prayers and ablutions at definite hours 

 of the day and night required an accurate determination of time, while 

 the motion of the moon had to be observed in order to fix the dates of 

 their feasts. From these and similar reasons the Arabs became active 

 in astronomical research, and in consequence developed the auxiliary 

 science of trigonometry. 



The turmoil attendant upon the invasion of the ancient world by 

 the Teutons and Saracens so obscured the progress of civilization that 

 this period, although in reality one of beginnings, is known in history 

 as the Dark Ages. The most important feature of this vast influx of 

 barbarians, so-called, was the rapid conversion of the Teutons to Chris- 

 tianity. A colder climate had bred in them a more vigorous mentality 

 and a higher type of morality than that of the south, and Christianity 

 appealed with especial force to their innate love of freedom and spirit 

 of brotherhood. History thus far had been a record of the physical 



