"Tolometh" by Clark Ashton Smith

similor: an alloy of copper and zinc, resembling brass but of a golden color

pard: short for leopard

architraves: a main beam resting across the tops of columns, specifically the lower third entablature

hecatomb: a great public sacrifice, originally (in ancient Greece) of a hundred oxen

The picture used is the mushroom cloud of Gadget during the Trinity tests, July 16, 1945.

To follow along: http://www.eldritchdark.com/writings/poetry/604/tolometh

Have to wonder if the hell-black wizardries referenced includes Malygris? We know Malygris had tomes detailing long-lost gods, so it seems probable he knew of Tolometh, and perhaps called upon him to aid him in his magical endeavors.