I’d have said at first its just the halides being pulled into the arc stream, but I’ve actually, (albeit very rarely), seen mercury arcs pull a tiny pink orb into the arc too!
Wonder if it’s tiny pieces of glowing electrode coming off?

 I've been a member here for 6 yeras now and I see lots of people discussing older HPS or MH fixtures believing that they must've been originally MV and were converted to MH or HPS . Not always the case . I've seen several instances of 60's fixtures which were available in MH and HPS also .  For example , LM Unistyle 400 & Unistyle 1000 were available from the factory in all 3 flavors . The M-400A was also .  Mid 60's Revere catalogs list both MV and "Metallic Additive" versions .

 I've seen some of which more are originally HPS than MV , i.e. AEL 25 , LM Unidoors , M-400A .

 Running the drill slowly is a must as turning it at a high speed just generates heat and kills the bit quickly !

Just spent 5 hours... attempting... to drill out a broken bolt in my rear strut mount of my sport car. Failed miserably.
I've tried right handed drill bits with penetrating oil, left handed drill bits with penetrating oil, several extractors
including the famous "Grabit" extractors. Everything failed, miserably. The Grabit extractor actually slipped out of the
drill.
Either the drill is very weak, or maybe I'm doing something wrong.
And yes, I reversed the drill for the extractors and the left handed drill bits.

I find drilling out stuff like this, it's critical to use a quality drill bit. I usually go with a decent cobalt bit, those go through steel a lot easier than standard HSS bits. The other option would be to attempt to cut the bolt. I used a dremel to cut the bolts on my sway bar links when I replaced them. 

 I quickly learned to apply the brakes on the Mustang using my heel instead of the normal method , your toes . As for the bicycle , last time I went over the bars , I ended up in a blackberry bush !! 

 My most memorable bike incident damn near killed me ! I had bought an old 3-speed bike at a garage sale for next to nothing and rode the daylights out of it . It had the Sturmey-Archer 3-speed mech. and full chrome fenders with cable brakes .  When I bought it , the rear fender had the mount which holds it to the frame by the rear brake had come loose from the fender . It was still attached at the rear and at the front so I never bothered with it even though it rattled like hell . WELL , one day I was riding to my friends house and going down a long hill as fast as I could peddle in 3rd gear . I hit a small bump in the road which caused the now fatigued front mount to also fail which then let the fender fall onto the tire , rotating it so the fender was between the tire and the road ! NOT GOOD !!!  The bike ended up totaled I I wound up in the Emergency room !!   

I can see how that would be a problem... 
I remember the time I was out cycling when the cable for the rear brakes snapped.! 
I was going down a fairly steep hill that had a series of 90^o bends on it, I got round two of them at about 30mph, but came off at the third and went sailing over the handlebars, fortunately landing in a soft newly dug flowerbed.!

Anyone chuckle a bit when you read those strangely worded/AI generated lighting descriptions on sites. Here's a couple I found:

Philips RELB2S40N, Ballast 2 Bulb Electronic T-12
"Genuine OEM replacement part
 Phillips is well known in the food industry for providing quality products
 Use genuine OEM parts for safety reliability and performance"

Slimline T12 60 W Fuorescent Tube - 96" - Cool White
"This 96" 60-watt T12 fluorescent lamp is instantly illuminated thanks to Sylvania's unique "Supersaver" system. The phosphorus tube emits a deluxe cold white brightness for a 4100 K color temperature."

I don't generally associate the brand Philips with the food industry, and I didn't know "Supersaver" was a method of starting fluorescent lamps. 

 The power steering in my old van has been dead for over a year now . As long as you're moving , it's not too bad but if your stopped or moving slowly , i.e. trying to go into or out of a parking space , IT'S AWFUL !! .

 I've driven plenty of vehicles with no power steering and some with no power brakes . After awhile , you do get used to it a bit .  The '66 mustang I used to own had non-power , drum brakes at all 4 corners . Once you got used to it and learned to apply more initial pressure , it stopped similar to a modern car . The issue was when you got back into a "normal" car with 4 wheel power disc brakes you'd just about launch yourself thru the windsheild the 1st time you tried to stop !! 

I think 250w and 400w HX ballasts weren't too uncommon during the heyday of MV as certain types of fixtures had them or was a option for some others. 175w was just more common as about every 175w MV yardlight used a HX ballast.

HX ballasts seemed to be pretty hard to find standalone though. A lot of aftermarket kits were CWA, although the NEMA specific kits were all HX.

 If the pipe was vertical it was probaly to either keep the carts in the store or so employees could see where the carts/customers were .