290 iliny's natural histoet. [Book XXXV. 



within a frame of boards, constructed on either side. These 

 walls will last for centuries, are proof against ram, wind, and 

 fire, and are superior in solidity to any cement. Even at this 

 day, Spain still beholds watch-towers that were erected by 

 Hannibal, and turrets of earth^^ placed on the very sumrnits of 

 her mountains. It is from the same source, too, that we derive 

 the substantial materials so well adapted for_ forming the 

 earth-works of our camps and embankments against the impe- 

 tuous violence of rivers. What person, too, is unacquainted 

 with the fact, that partitions are made of hurdles coated with 

 clay, and that walls are constructed of unbaked bricks? 



CHAP. 49.— WALLS OF BRICK. THE METHOD OF MAKING BRICKS. 



Earth for making bricks should never be extracted from a . 

 sandy or gravelly soil, and still less from one that is stony ; 

 but from a stratum that is white and cretaceous, or else im- 

 pregnated with red earth.«^ If a sandy soil must be employed 

 for the purpose, it should at least be rnale^' sand, and no other. 

 The spring is the best season for making bricks, as at midsum- 

 mer they are very apt to crack. Eor building, bricks two 

 years old are the only ones that are approved of; and the 

 wrought material of them should be well macerated before 

 thev are made. 



There are three different kinds of bricks ; the Lydian, wJuck 

 is in use with us, a foot-and-a-half in length by a foot m 

 breadth ; the tetradoron; and the pentadoron ; the word ''doron 

 being used by the ancient Greeks to signify the palm^— hence, 

 too, their word " doron" meaning a gift, because it is the 

 hand that gives.— These last two kinds, therefore, are named 

 respectively from their being four and five palms m length, 

 the breadth being the same. The smaller kind is used m 

 Greece for private buildings, the larger for the construction of 

 pubHc edifices. At Pitane,^' in Asia, and in the cities of Max- 

 ilua and Calentum in Farther Spain, there are bricks^ made, 

 which float in water, when dry ; the material being a sort of 



«3 See B. ii. c. 73. «^ "Rubrica." ^^ See B. xxxi. c. 28 



86 Which was, as a measure, nearly three inches in hreadth. bee Intro- 

 duction to Vol. III. '' See B. v. c. 32 , 



88 Aiasson says that these bricks have been imitated by Fabroni, -with a 

 light argillaceous earth, found in the territory of Sienna. Delatosse thinks 

 tlfat a place called " Gala," in the Sierra Morena, probably marks the site 

 of the cities above mentioned. 



