Older parts of downtown Oakland feature these iron grates in the sidewalk. Unlike the purple glass and concrete “vault lights” you’ll also see around downtown, the grates were for ventilation. I collected the following photos during an hour’s walk east of Broadway between 19th and 14th Street.
Here are two sizes of grate from the Phoenix Sidewalk Light Co. of San Francisco.
Please note that these are not sidewalk lights (vault lights), but ventilation grates. Phoenix made both items, according to the Historic Prism Glass Companies of the United States list on glassian.org. It was headquartered in the Monadnock Building on Market Street.
John McGuigan & Co. was also across the bay, at 144 Stillman Street. (The address is now under the freeway.)
The king of the business appears to have been P. H. Jackson & Co., which was a major manufacturer of reinforced concrete and other innovative building elements beginning in the 1870s in San Francisco. The company, on the 200 block of First Street, continued business well into the 20th century. I will have more to say about the company in a future post.
Here are three different examples of their products.
This is an unexpectedly deep subject!
Oakland Underfoot 
19 February 2016 at 9:15 am
What’s with that last “grate” from the Jackson co.? Looks like it was modified- before or after placement, I wonder.
19 February 2016 at 10:46 am
My theory — just a story, really — is that it replaced a real ventilator because the original one was a problem somehow, like it let in too much rainwater.
19 February 2016 at 11:42 am
I love these posts. If you haven’t done so already, how about documenting the big steel sidewalk grates that provide access to basement storage? There’s a good example in front of the Starbucks on 8th and Broadway that’s stamped “OAKLAND”.