BOOK V. I. 2-4 



the extensive material with which we have under- 

 taken to deal. For indeed subjects, which do not 

 properly belong to our profession, are demanded as 

 though they had been left out; for example, only 

 recently, when my friend Marcus Trebellius required 

 from me a method of measuring land he expressed 

 the opinion that it was a kindred and indeed closely 

 connected task for one who was showing how we 

 ought to trench land to give instructions also how we 

 ought to measure the land thus trenched. I replied 

 that this was the duty not of a farmer but of a sur- 

 veyor, especially as even architects, who must 

 necessarily be acquainted with the nnethods of 

 measurement, do not deign to reckon the dimensions 

 of buildings which they have themselves planned, 

 but think that there is a function which befits their 

 profession and another function which belongs to 

 those who measure structures after they have been 

 built and reckon up the cost of the finished work by 

 applying a method of calculation. Therefore I hold 

 that excuse should rather be made for our system 

 of instruction if it only goes as far as to state by what 

 method each of the operations of farming should be 

 carried out and not the area over which it has been 

 performed. But since, Silvinus, you also ask us in a 

 friendly spii'it for instructions about measure- 

 ments, I will comply with your wish, on condition 

 that you harbour no doubt that this is really the 

 business of geometricians rather than of countrymen, 

 and make allowances for any errors that may be 

 committed in a sphere where I do not claim to possess 

 scientific knowledge. 



But to return to my subject, the extent of every area 

 is reckoned by measurement in feet, and a foot consists 



