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I wonder if this is a remnant of the 1893 World's Columbian Exposition and the "Current War"? This is on Jackson Park's Wooded Island. It says: "Westinghouse Electric & Mfg. Co. Alternating System. Grimshaw Insulated Wire White Core." #ManholeCoverMonday
The 1897 National Electrical Code manual includes a listing for "Grimshaw (White core) N.Y. Insulated Wire Co." https://www.linghunt.com/101Spearfishing/Ref_manuals/NEC%200070-1897%20original.pdf
As the Tesla Memorial Society says, the 1893 world's fair in Chicago "was the final great victory of Tesla/Westinghouse's Polyphase Alternating Current system electricity over Edison's Direct Current (DC)." https://www.teslasociety.com/columbia_expo2.htm
"Wooded Island became the center of the fair, surrounded by lagoons and by over 200 buildings erected for the fair." This manhole cover is in the grass just south of the Japanese Garden, which was the site of the Japanese pavilion during the 1893 fair. https://www.chicagoparkdistrict.com/parks-facilities/jackson-park-wooded-island
Thanks to @ChiCollections for this 1892 article. So we have evidence that Grimshaw wires were used at the 1893 world's fair. I'm pretty convinced that this iron cover must be an artifact from the fair. https://twitter.com/ChiCollections/status/1325819710978580481?s=20
A @chicagotribune article from April 30, 1893, says "several hundred miles of Grimshaw wires" were used in the electrical lighting system at the World's Columbian Exposition.
The same article mentions "the sparkling lights on the wooded island."
Here's the Wooded Island on "Bird's eye view of the World's Columbian Exposition, Chicago, 1893." https://www.loc.gov/resource/g4104c.pm001522/?r=0.096,0.112,0.321,0.198,0
Westinghouse and Nikola Tesla had displays in the Electricity Hall, which was east of the lagoon. Images from the Tesla Memorial Society's website. https://www.teslasociety.com/columbia_expo.htm
More details here about "The Current War" (as it was called in a 2017 movie) and the 1893 World's Columbian Exposition: http://projects.leadr.msu.edu/makingmodernus/exhibits/show/electrifying-america
