de re naturam

the Romans knew volcanic ash was key
to make cement that stands the test of time
that sets up hard on land, or under-sea
without the silicates, it's merely lime
that lore was lost for fifteen hundred years
cathedrals soar, but aren't weather-proof
staff masons keep up with the wear and tear
but it's a loss if you neglect the roof
petrology would catch up down the road
explaining how the crystal lattice binds
but brute empiricism bore the load
explaining aggregate in all its kinds
the best of Roman technology stands
the failures long since crumbled back to sands