ConstrRucTING ARCHES. AT9 
Havine witnessed with great curiosity the operation I haye 
endeavoured to describe, I deem its communication may prove 
of utility, in the construction of bridges, domes, and other 
aaches, or vaulted buildings. 
| I have the honor to be 
SIR, 
Your very Obedient humble Scurvant, 
Bb. MACKINTOSH, 
Captain Madras Artillery. 
| 
