Quicksilver

The rotating optics of lighthouses used to float on a bed of mercury.

Dave
The Emerald Isle

In terms of huge volumes of Hg, the Castner-Kelner process for producing chlorine and caustic soda by the electrolysis of brine is worth a mention. The old ICI "cell rooms" in Cheshire were incredible; in each, the amount of Hg could be around 100 tons, the current required upto 200,000 amps at 200V. The gap between the electrodes and the Hg surface was very critical for efficiency - too close and imagine the result !
Hazards of Hg were well known in the 60s and workers were routinely monitored. Mercury vapour was released along with the hydrogen from electrolysis and traps were needed to recover the liquid Hg. When the diaphragm process began to replace the mercury process from the mid 70s those huge volumes of Hg would have had to have been disposed of - maybe sold?

But back to reminiscences of school days in the chemistry lab., as others have mentioned the inevitable little globules of Hg would collect in the benchtop grooves. At my school we were required to use only fountain pens for note taking. The rotten trick was to take someone's pen, with its gold nib when they were not looking and press the nib in to the Hg. The resulting amalgam would to cause the nib to disintegrate and the pen's owner distress.

If your hypothetical friend decided to get rid of the problem by pouring it out into the ground (which was a common way in the past to get rid of unwanted chemicals) it could cause a huge problem which would certainly result in prosecution as well as a major health risk.

At school in physics class we were allowed to stick our fingers in the mercury and do various other experiments with it. In chemistry class we created small quantities as a product of a reaction and the teacher would be jumping around to make sure we flushed it down the sink pdq. (where it settled nicely in the trap) Silly thing was that the salt we started with would be poisonous and the liquid safer until reacted into a salt again. The panic was about the potential of the liquid turning to fumes which are extremely hazardous but which wouldn't really happen until a fire. I assume nowadays schools just do computer simulations of all science experiments to be on the safe side.

So the real worry for the op's friend is having it in the house during a fire as the firemen will be really puzzled that the corpses were found in a room that was hardly affected by smoke.

The head of science at my school in the 60s was a crusty old gent who had equipped the physics labs after the war with surplus meters etc - you haven't lived until you've used an altimeter to balance a Wheatstone Bridge! Amongst other things he bought a crate of bottles of mercury which lived in the cellar - I think they had got through a couple of bottles by 1968, where it went who knows!

Regarding mercury arc rectifiers, these don't emit x-rays. In the machines lab at uni there was a test setup with a 3-phase one in a big steel cabinet where you could look at the arc through a strobe disc, if you got the speed right you could see the arc stepping from electrode to electrode as the phases changed. The technician used to warn us against opening the door because of the UV, but the machines lecturer encouraged it, pointing out accurately that the glass stopped nearly all the UV. Great fun.

Just checked my (UK) local council waste disposal website and it says that the usual dump site takes mercury and other chemical stuff. Seems pretty sensible because I guess no-one wants that sort of stuff chucked in the nearest hedge or pond.

Rather leaving themselves open though, I suspect the denizens of this site might know of many nasty substances lurking in attics and basements.

Way back telephone exchanges used mercury arc octopuses. Lots of fun when one broke and about 1 pint of Hg spilled on the floor..... More fun when someone went to change one of them new fangled germanium rectifiers and diligently turned off the mains but forgot to isolate the battery. Much very quick movement.....

Samsaranda - mixing mercury and aircraft was always tricky ! The Britannia you mentioned was a complete write-off - no possible way of tracing all the little globules. Can't remember which, but I seem to remember that at least one of my operational types had mercury triggered crash switches. Post retirement, I worked part-time in a watch and clock shop for a friend. He informed me one morning that he had dropped and broken a stick barometer the previous evening and had swept the resultant mess into the rubbish bin. I did an online search and showed him the results - he was suitably impressed!!

rgds

Bill

I remember one day in school general science class one of the girl s was most upset, her gold signet ring had turned silver, she had had a small amount of mercury rolling around on the palm of her hand. I also rem,ember about a similar time when I would open the little mercury button cells after they went flat, and squeeze out the mercury, I had a little jar with about 1/2 an inch of mercury from a number of sources, don't know where that went.

When I was nursing, it was infrequent, but on occasions someone would drop a rack of clinical thermometers (usually 30), back in the 1970s it was just a case of sweeping up as much as possible and putting it in the dangerous goods rubbish (all those little bits of glass).

Ian S C

At least 1 747 has been scrapped after mercury contamination.

There's a condition called Minamata disease.

It affected people who ate fish caught from areas of the sea around Japan contaminated by mercury pollution.

But I handled mercury as a kid so it can't be dangerous...

Neil

P.S. One chemistry teacher needed to dispose of some sodium that was considered too large to be safe for school use (even in the 70's). He threw it in the school pond and legged it Apparently there was a large ball of flame and the pond was emptied.

P.P.S. I spent a quarter of an hour being irrigated after someone else put a small piece of sodium in a dry sink...

Before chucking it away know that a ton of mercury at wholesale prices would set you back nearly $68000. Iron is less than $100 / ton. Mercury may not be in the same league as Gold, but still...

PS Mercury metal isn't dangerous, but the vapour is.  A few individuals are much more sensitive than most of us which is why schoolkids don't play with it any more.  Although the risk is low, most headteachers think one 999 call is too many. 

Most chemical compounds containing Mercury are poisonous and quite a few are off-the-scale deadly.  The lady mentioned earlier was a Professor of Toxicology, fully qualified and equipped to handle the chemical that killed her.  She was poisoned through an intact rubber glove.

Dave

Edited By SillyOldDuffer on 04/06/2019 16:15:34

Crikey! That's a blast from the past! I was a fitter in those cell rooms, we regularly had 'piss tests' to monitor our Hg levels. Mercury seemed to be everywhere! When we 'hogged' the cell base plate we had to run the Mercury pumps to check the flow was straight down the middle of the cell for peak efficiency, it was a really beautiful sight to see a river of mercury shimmering down the base plate. The main cell rooms were 'J' 'K' and 'L' units. J and K ran at 200,000 amps and L unit ran at 400,000 amps.

The other big issue apart from Mercury was the powerful magnetism, which played havoc with steel toe capped boots!

Bill, later in my career in the Air Force I was working as an NDT technician at Brize Norton and a VC 10 arrived back from a casualty evacuation and it transpired that one of the nursing staff on board had dropped and smashed a mercury thermometer. As the easiest way to detect mercury was by x-ray, the mercury being rather dense shows up brilliantly against light alloy structures; the duty engineering officer called us down to the aircraft and decided that we were going to x-ray the floor area where the thermometer had been broken. We asked if any of the mercury had been retrieved and it was pointed out that approx half of the contents had been retrieved using a mercury retrieval kit which meant that there was an amount the size of a 2 - 3 mm size ball still missing. The engineering officer was insistent that we had to x-ray to account for the missing amount, he had mapped out an area of about 5 square metres of floor space as the area of interest. The first task was to check for access under the floor to place our x-ray films, we went into the underfloor space, it was the electronics and navigation equipment bay and was crammed to the ceiling with equipment, we made our way back up to the main cabin and explained the situation to the duty engineer, he insisted that it had to be done so we said we’ll give us a call when you have removed all the equipment under the floor so that we can place film, we then left the aircraft and heard no more from him so I can only assume that the aircraft was deemed fit to fly with the tiny amount of mercury still rolling around, to my knowledge the aircraft continued to fly like this until it was phased out of service with all the other VC 10’s some 30 years later.

Dave W

Exactly the same thing in Ireland. The relevant minister can issue an S.I, a statutory instrument, which is basically an amendment to the act, without consulting anyone. Democracy is unfashionable currently, especially with institutions like the Eu. Which as we have seen in the past few, leaned on Switzerland, who are not even a member of the eu, to amend their historically liberal gun laws.

Didn't W.G Armstrong use mercury in his lighting system In his country pile, Cragside ? The first house in the world to have electric lighting ?

High vacuum diffusion pumps used to use large volumes of mercury. There were regular stories ( all apocryphal I'm sure ) about people trying to steal some from our establishment and being caught by security on the exit gate. They usually involved a push bike frame being filled with mercury and then being dropped and being too heavy to pick up or the bike falling apart because the mercury had dissolved the spelter joining the lugs to the tubes.

Rod

This is an interesting thread. I remember playing with mercury as a kid. I had obtained a small bottle of it from somewhere. Use to run it round palm of hand and across desks etc. I lost it somewhere in my parents house. I've just found an old Twaddell's Hydrometer No. 1 which has a glass bulb of mercury in the bottom. I think I've had it lying around for at least 50 years. And the more I think of it somewhere I have some glass tilt switches with mercury in them.

Colin

In one school I worked at during the last 30 years or so (genuinely can't remember which) they still had mercury barometer troughs in the physics lab.

Imagine a porcelain dish about 4" long and 3/4" wide and the same tall except one end of the trough widened out to be circular - about 1" diameter - sort of a keyhole shape in plan view or a midget version of one of those baths you can have a shower in.

When I enquired what this strange dish was used for it was explained that you filled it half full with mercury, filled up a glass tube with one end sealed right to the top with mercury, put your finger over the end of the tube, inverted it an placed the tube under the surface in the dish in the circular end before removing your finger, leaving a basic barometer. The trough was shaped to accommodate your finger that could then be removed and the tube supported in a clamp stand.

I never had the courage to demonstrate it - but no doubt I would have been allowed to do so!

The best thing was that there were a class set of these things - Imagine how much mercury would have been needed, how much it would cost and even with a well organised class how much would end up on the floor.

Organic compounds of mercury are extremely toxic, methyl mercury that was the cause of the Minimata disaster.

I was told by a doctor that the danger from the old style clinical thermometers was from the broken glass if the patient bit it. The mercury would pass harmlessly through the body before it had time to break down into something easily assimilated.

I had a few panicky minutes when I blew a mercury manometer over an aircraft oxygen regulator that I was testing. Fortunately for me, it was the anodising that protected the aluminium regulator.

We kept mercury in cast iron pots or polypropylene containers.

It may be an apocryphal story but was informed that the low hrs E.E Lightning in RAF Hendon museum in '70s had been retired due to mercury spillage in cockpit.
DaveD