236 



On a Mode of erecting liyht Vaults 



profile ; but arcs doubleaux when, as at E, they divide two 

 compartments r>. vaulting from one another, and thus acquire 

 a stronger profile. He then gives a drawing, with an explana- 

 tion for laying down these different lines, and concludes very 

 naively 



1 Si quelques-uns desirent en scavoir davantage pour le pra- 

 tiquer, faut qu'ils s'addresserit aux architectes ou maistres 

 magons qui 1'entendent. Car il est mal-aise de le pouvoir 

 mieux expliquer, que par oeuvre et effect, c'est a dire en demon- 

 strant au doit et a 1'ceil, comme les pierres se doivent trasser 

 et assembler.' Subsequently, in the 9th chapter, De 1'Orme 

 gives a design for a simple vault over a church ; recommends 

 the laying the lines of the ribs exactly in the circle, that no 

 chink (aucun jouef) may occur; the not driving any large 

 wedge into the joints of the ribs ; the vaulting the pannels of 

 the vaulting (pendentifs) with brick or small stones ; the laying 

 the courses horizontally and according to the proper section of 

 the joints ; also the putting little thin mortar in the joints ; and 

 insures the durability of such vaults in the words ' telles 

 voutes faictes ainsi dureront long temps.' 



In the 10th chapter he adds a design out of his Nouvelles 

 Inventions de Charpenterie, published in 1561, in order to 

 shew that similar vaults may be constructed with wooden ribs 

 and hanging keystones ; but he himself is of opinion that it is 

 better to execute these in hewn stone. He then speaks of the 



