Chap. M ] THE VARIOUS KINDS OF SAND. 3/3 



The reticulated 45 kind of building, which is mostly in use 

 at Home, is very liable to crack. 46 All building should be 

 done by line and rule, and ought to be strictly on the per- 

 pendicular. 



CFIAP. 52. (23.) CISTF.ltNS. 



Cisterns should be made of five parts of pure, gravelly, sand, 

 two of the very strongest quicklime, and fragments of silex 

 not exceeding a pound each in weight; when thus incor- 

 porated, the bottom and sides should be well beaten with iron 

 rammers. The best plan, too, is to have the cisterns double ; 

 so that all superfluities may settle in the inner cistern, and 

 the water filter through, as pure as possible, into the outer 

 one. 



CHAP. 53. QUICK-LIME. 



Cato 47 the Censor disapproves of lime prepared from stones 

 of various colours : that made of white stone is the best. 

 Lime prepared from hard stone is the best for building pur- 

 poses, and that from porous stone for coats of plaster. For 

 both these purposes, lime made from silex is equally rejected. 

 Stone that has been extracted from quarries furnishes a better 

 lime than that collected from the beds of rivers ; but the best of 

 all is the lime that is obtained from the molar-stone, 4 * that beicg 

 of a more unctuous nature than the others. Il is something 

 truly marvellous, that quick-lime, after the stone has been sub- 

 jected to lire, should ignite on the application of water ! 



CHAP. 54. THE VAUIOUS KINDS OF SAND. THE COMBINATIONS 



OF SAND WITH LIME. 



There are three kinds of sand : fossil 49 sand, to which 

 one-fourth part of lime should be added; 30 river sand : and 

 sea sand ; to both of which last, one third of lime should be 

 added. If, too, one third of the mortar is composed of bruised 

 earthenware, it will be all the better. Fossil sand is found in 

 the districts that lie between the Apennines and the I'adus, 

 but not in the parts beyond sea. 



45 Where the outer face of cncli stone forms an exact square ; the poiiit- 

 fops consequently having a intliko or reticulated appearance. 

 4G The vertical pointings or junctures lyiii one over the other. 

 V? Ke Rust. c. 38. " Jk-c Chapters '29 and 30 of this Book, 



To which I'ozzuulauc belongs. & L'or making mortar. 



