374 | ANNUAL REPORT SMITHSONIAN INSTITUTION, 1944 
In the Chou kingdom in China, 1000 B. C., the minister of war was 
known as “The Master of the Horses.” 'The Chous had no currency. 
Taxes were collected in kind, and the chief tax gatherers were known 
as “bullock drivers.” For many centuries over wide areas in three 
continents kingdoms were measured by the number of chariots they 
could put in the field. (See King Solomon.) 
A recent writer, Bates, emphasizes the acute shortage of power 
among the Romans on both sea and land. This power shortage led 
to the use of the galley slave at sea and of slaves to turn the mill and 
EEE MP =) sasce 
a GA 
Mae 
SLKL 
5 
SS 
Cex S 
SSS 
CE OO 
DSSS 
SS 
eS 
SOK 
300 
Ficure 13.—The extent, A. D. 750, of the caliphate, the Arab Mohammedan empire 
founded by Mohammed. (Base map copyright by Rand McNally & Company, 
Chicago.) 
to do other drudgery on land. Bates alleges that Roman wars were 
often little more than slave-gathering expeditions. 
In the ninth century A. D., someone, apparently in France, invented 
the horse collar and traces. A horse could then pull a load. Then, 
as Mr. Bates tells us, horses could really work and enter the economic 
realm. Horsepower became cheaper than slavepower, and slavery 
gave way toserfdom. As mechanism improved, serfs became freemen. 
Inventions gave man equipment that permitted him to emerge from 
the slave age. At a much earlier time inventions had ushered in the 
Stone Age. Most important inventions change man’s relation to some 
part of the earth. 
