In studying the history of local infrastructure, I was reading about the early years of a local electrical company, and came across the event installing the the first street lights. It was in 1888, and the lights, at first lit, were said to have dazzled the crowd. The story says, that someone even cried "Moon, you should be ashamed!" 

The lights were firs lit with a power form a dynamo built by a british inventor. The name of the inventor was Elihu Thomson of Thomson et Houston. I searched for their designs, and found these beautiful old drawings, from patent pictures from the end of the 19th century.

I thought this would make a beautiful cover, that would both work as an ornament, while still carrying a story from the city's past.

The section of Thompson's dynamo recreated on a sewer cover.