54 TREATISE ON 



& coarse sand, they'll last a long time. 6°. Others construct studworks filled in with 

 pugging mortar, but these don't last very long, & the pugging mortar separates from the 

 wood leaving holes where insects can hide. 7°. A fence made entirely of boards would be 

 better, but it would be expensive & won't last long, even when oil-painted. 8°. Walls of 

 dry stones, i.e. without mortar & without coating, are the worst of all. They shelter and 

 protect trees poorly because they provide a haven for pests to hide & multiply in safety. 



Walls are built from a minimum of seven feet high up to a maximum of fifteen 

 feet. When the wall is four to six inches above the surface of the ground, it's a good idea 

 to place at that point an inch-&-a-half or two inch offset on which to set the ends of the 

 vertical slats of a trellis. 



1 1. A coping is necessary to protect the walls, their coatings, & trellises, that 

 otherwise soon would be deteriorated & ruined by rain. The coping should project at least 

 four inches; it can be fashioned in different ways & from different materials. 



1°. Putting the stones together without mortar, even though they overlap, will 

 result in a structure that's of little use & hardly sturdy. 



2°. In regions that have flat stones of slate or schist large enough to cover the 

 whole thickness of the wall & project as necessary, two overlapping rows of these stones 

 make a suitable & durable coping. 



3°. The most common copings, ones that can last in good condition for nine or ten 

 years & sometimes longer, are made of flat & hard ashlars overlapped with other ones of 

 the same quality. The whole is set with plaster or with a good mortar of lime, sand, & 

 cement. 



4°. Very good copings are made with two rows of tiles 



