What are those grids of glass in the sidewalk and why are they purple? • Hacker News Board

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

#81

Post by EB66 » Sat, Jan 04, 2020, 4:13 AM UTC

BinaryIdiot wrote: post #72

This is fascinating. I've walked over those countless times and always wondered what they were. I am curious about this one bit though: > When vault lights were first installed, much of the glass was clear. But when the manganese is exposed to UV rays for long periods of time, it photo-oxidizes and turns purple or pinkish. Hence, the reason so much of the glass is now purple. > This process can take decades. So when…

IIRC maganese was used by virtually all American glass manufacturers from the 1800s til 1920ish. So I suppose if the glass was dyed purple, it would turn more purple as it was exposed to UV but only if the glass was manufacturered during that time period.

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

#82

Post by meddlepal » Sat, Jan 04, 2020, 4:25 AM UTC

rconti wrote: post #38

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.

I did it last time I was out there..., I had fun and some time to kill before my flight.

The tour guide makes the tour interesting. The actual sights are cool but you're effectively on a guided tour through maybe a few small blocks of buried sidewalk. It is not earth shattering stuff though the history is definitely cool.

In the end it was worth the ~$40, $20 for the tour I think, and I felt generous so I gave the guide a big tip since he was hilarious and took us on a slightly extended route according to some folks who had done the tour in the past.

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

#83

Post by brodie78382 » Sat, Jan 04, 2020, 4:45 AM UTC

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…

We have these old glass grids in the sidewalks along College Ave up here in Fort Collins as well. Some are even still in use by restaurants to load inventory from the Cysco / Shamrock trucks.

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

#84

Post by jrochkind1 » Sat, Jan 04, 2020, 4:48 AM UTC

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...)

They weren't clearing the sidewalks to let light through, they were (and we are) clearing the sidewalks so that people could walk on them! Anyway, with or without prism tiles.

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

#85

Post by Benjammer » Sat, Jan 04, 2020, 4:58 AM UTC

inferiorhuman wrote: post #79

chrisseaton wrote: post #62

Earlier quoted context omitted.

> the old Pennsylvania Station It wasn't that old! It was only built in 1910, and using modern techniques! It wasn't an ancient monument as you probably think it was, and it was only around for a few decades. Equivalent of a 1960s building being knocked down today.

Equivalent of a 1960s building being knocked down today. There are plenty of buildings from the 60s I'd be sorry to see go. At the top of the list is the Marin County Civic Center and the TWA Flight Center.

JetBlue turned the TWA center into a hotel, I don't think they plan on getting rid of it any time soon.

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

#86

Post by kaishiro » Sat, Jan 04, 2020, 5:07 AM UTC

Benjammer wrote: post #85

inferiorhuman wrote: post #79

Earlier quoted context omitted.

Equivalent of a 1960s building being knocked down today. There are plenty of buildings from the 60s I'd be sorry to see go. At the top of the list is the Marin County Civic Center and the TWA Flight Center.

JetBlue turned the TWA center into a hotel, I don't think they plan on getting rid of it any time soon.

And a rad one at that - stayed there on the way through JFK a few weeks ago. If you’re feeling fancy you can even take a Blade helicopter into the city - they have a desk right at TWA.

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

#87

Post by thematt » Sat, Jan 04, 2020, 5:26 AM UTC

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.

https://mashable.com/2015/08/18/building-seattle/

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

#88

Post by philwelch » Sat, Jan 04, 2020, 5:35 AM UTC

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.

If you've already done the normal underground tour, there's also a late-night version where they talk about the seedy underbelly of early Seattle, i.e. all the prostitution and body-snatching and other assorted crimes. Or at least there used to be one.

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

#89

Post by greglindahl » Sat, Jan 04, 2020, 5:42 AM UTC

Benjammer wrote: post #85

inferiorhuman wrote: post #79

Earlier quoted context omitted.

Equivalent of a 1960s building being knocked down today. There are plenty of buildings from the 60s I'd be sorry to see go. At the top of the list is the Marin County Civic Center and the TWA Flight Center.

JetBlue turned the TWA center into a hotel, I don't think they plan on getting rid of it any time soon.

It’s pretty beautiful inside.

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

#90

Post by ehnto » Sat, Jan 04, 2020, 6:13 AM UTC

lqet wrote: post #52

> Vault lights were used to light some of New York City's first subway stations and were placed in the ground of the opulent passenger concourse in the city's original Pennsylvania Station. I will never get my head around the fact that the old Pennsylvania Station was destroyed. It must be one of the biggest mistakes in urban development of the 20th century. > Another architectural critic, Ada Louise Huxtable, wrote…

Lost craftsmanship and cost of construction has risen so much that some projects just couldn't be afforded anymore. My city once had an extensive rail network, it was torn out in favour of cars. Now that we want to put it back in, construction costs are so inflated we can't afford it.