BOOK XXXV. xLvii. 167-XLIX. 170 



from the dust of Pozzuoli, not to be used for an 

 embankment against the sea and to act as a break- 

 water against waves, but for the purpose of sub- 

 duing men's bodies for the exercises of the wrestling 

 school. At all events it used to be imported from 

 there for Patrobius, a freedman of the emperor 

 Nero, and moreover I also find that this sand 

 was carried with other mihtary commodities for 

 Alexander the Great's generals Craterus, Leonnatus 

 and Meleager, though I shall not say more about 

 this part of the subject any more than, by heaven, 

 I shall mention the use of earth in making oint- 

 ments, employed by our young men while ruining 

 their vigour of mind by exercising their muscles. 

 XLVIII. Moreover, are there not in Africa and 

 Spain walls made of earth that are called framed 

 walls, because they are made by packing in a frame 

 enclosed between two boards, one on each side, and 

 so are stuffed in rather than built, and do they not 

 last for ages, undamaged by rain, wind and fire, 

 and stronger than any quarry-stone ? Spain still 

 sees the watchtowers of Hannibal « and turrets of 

 earth placed on the mountain ridges. From the 

 same source is also obtained the substantial sods of 

 earth suitable for the fortifications of our camps 

 and for embankments against the violent flooding 

 of rivers. At all events everybody knows that 

 party-walls can be made by coating hurdles with 

 clay, and are thus built up as if with raw^ bricks. 



XLIX. Bricks should not be made from a sandy Brkks. 

 or gravelly soil and far less from a stony one, but 

 from a marly and white soil or else from a red earth ; 

 or even with the aid of sand, at all events if coarse 

 male sand is used. The best time for making bricks 



385 



