ROME: VITRUVIUS 37 



and to pay the salaries of the teachers. Finally, 

 in the fourth century A.D., further measures were 

 adopted by the State. The Emperor Constantine 

 writes to one of his officials : " We need as many en- 

 gineers as possible. Since the supply is small, induce 

 to begin this study youths of about eighteen years 

 of age who are already acquainted with the sciences 

 required in a general education. Relieve their par- 

 ents from the payment of taxes, and furnish the stu- 

 dents with ample means." 



Pliny the Elder (23-79 A.D.), in the encyclopedic 

 work which he compiled under the title Natural 

 History, drew freely on hundreds of Greek and 

 Latin authors for his facts and fables. In the selec- 

 tion that he made from his sources can be traced, as 

 in the work of Vitruvius and other Latin writers, the 

 tendency to make the sciences subservient to the 

 arts. For example, the one thousand species of plants 

 of which he makes mention are considered from the 

 medicinal or from the economic point of view. It was 

 largely in the interest of tlieir-pratrtical uses"that the 

 Roman regarded both plants and animals ; his chief 

 motive was not a disinterested love of truth. Pliny 

 thought that each plant had its special virtue, and 

 much of his botany is applied botany. So compre- 

 hensive a work as the Natural History was sure to 

 contain interesting anticipations of modern science. 

 Pliny held that the earth hovers in the heavens up- 

 held by the air, that its sphericity is proved by the 

 fact that the mast of a ship approaching the land 

 is visible before the hull comes in sight. He also 

 taught that there are inhabitants on the other side of 

 the earth (antipodes), that at the time of the winter 



