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What are those grids of glass in the sidewalk and why are they purple?

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Re: What are those grids of glass in the sidewalk and why are they purple?

#31

Post by DanBC »

im3w1l wrote: post #19

One thing I would have liked the article to explain is when this is preferable over solid glass.

The earliest patent of deck lights, which predate vault lights or sidewalk prisms, is from 1684.

This site includes some images and patents https://glassian.org/Prism/index.html

There's a patent for sidewalk prisms from 1834.

As other people have said, the glass broke.

> In 1834, Edward Rockwell patented a round iron plate with a single large lens, but Hyatt later complained in his own patent application, "These glasses are extremely liable to fracture, and when broken leave large and dangerous openings within their rims...". Rockwell's plates are rare today; I know of only three examples of the iron covers and none of the lenses

Re: What are those grids of glass in the sidewalk and why are they purple?

#32

Post by SubiculumCode »

RangerScience wrote: post #10

Oh neat! I didn't know that Sacremento has this kind of underground. Also, anyone else having flashbacks to Dinotopia sunstones?

Indeed. I've been living in the area for some time now and had no idea. I wonder if there is some area that can be explored?

Re: What are those grids of glass in the sidewalk and why are they purple?

#33

Post by abuckenheimer »

altgeek wrote: post #6

In downtown NYC, there still are areas of sidewalk with these.

Just remembered the puck building[1] has these on the sidewalks surrounding the Houston street side, if you go into the Eastern Mountain Sports store and down the stairs you can see them from below.

[1] https://en.wikipedia.org/wiki/Puck_Building

Re: What are those grids of glass in the sidewalk and why are they purple?

#36

Post by rconti »

StClaire wrote: post #27

Denver has these, you can see them on Larimer and Market street in LoDo. Around the 1890s, the locals dug out a series of tunnels through the city. The snows would come in and people would just go underground for a few days for business. There was a bar that closed about a year ago called the Blake Street Vault—it used to be a bank—and if you asked they would take you into the basement to see the vault and the dumbwa…

Stupid question: Wouldn't the snow cover the vault lights? (I know, they could clear them by clearing the sidewalks...)

Re: What are those grids of glass in the sidewalk and why are they purple?

#38

Post by rconti »

taeric wrote: post #2

I thought this was going to be in Seattle. :) It is neat to notice these all over the place. The underground tour is more than a little crazy to see just how built up the city literally is. My favorite related topic were the spite mounds.

I grew up in Seattle. I still need to do the tour some day when I visit. So many cities have underground tours and I've heard great things about them.

Re: What are those grids of glass in the sidewalk and why are they purple?

#39

Post by jrace »

rconti wrote: post #36
StClaire wrote: post #27

Denver has these, you can see them on Larimer and Market street in LoDo. Around the 1890s, the locals dug out a series of tunnels through the city. The snows would come in and people would just go underground for a few days for business. There was a bar that closed about a year ago called the Blake Street Vault—it used to be a bank—and if you asked they would take you into the basement to see the vault and the dumbwa…

Stupid question: Wouldn't the snow cover the vault lights? (I know, they could clear them by clearing the sidewalks...)

It would. But not 100%. Same with skylights, depending on the depth and density some sunlight still makes it
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