Are mercury vapor lamps the ones that give out a sulfurous blue-yellow light that makes your skin look green - like you were dead?

They used to use a bulb like that in various passageways in the New York City Subway...they have been replaced with a yellow bulb - sodium, I presume?

Some huge warehouses, school gyms, etc. use these bulbs that give out a bright white light - sometimes it borders on ORANGE to the point it's PAINFUL (at least to me).

What is this one?

Also, why is it that every time I walk by one of these high-intensity weird lights the thing blinks off? [Linked Image]

[This message has been edited by SvenNYC (edited 04-10-2003).]