Ill 



over, the second to pass under: the first 

 is always necessary, the second only oc- 

 casionally so, as where the water under it 

 is navigable: yet, self-evident as this fact 

 may appear, bridges are often raised so 

 high, as to make the passage over them 

 difficult and dangerous, when no passage 

 under them is required; and perhaps a 

 form of bridge, adapted to the purposes 

 of passing over, which may unite strength 

 with grace, or use with beauty, is a desi- 

 deratum in architecture; for this purpose 

 I have suggested for several places, what 

 may more properly be called a Viaducty 

 than a bridge, of which no idea can be 

 given by description only. 



The width of a road must depend on Form of 



Roads. 



its uses: if much frequented, there should 

 be always room for two carriages to pass 

 on the gravel: if little frequented, the 

 gravel may be narrower, but there must 

 be more room left on each side; yet we 

 often see the broadest verges of grass to 

 the broadest roads, where in strict pro- 

 priety the breadth should be in an inverse 

 ratio. 



