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Comment by retrac | Hacker News Reader

There is a story to go with that story. The colonel responsible for the negotiations with the Treasury would later recall:

> He explained the procedure for transferring the silver and asked, "How much do you need?" I replied, "6000 tons."

> "How many troy ounces is that?" he asked. In fact, I did not know how to convert troy ounces to tons, and neither did he. A little impatient, I responded, "I don't know how many troy ounces we need, but I know I need 6000 tons - that is a definite quantity. What difference does it matter how we express the quantity?"

> He replied rather indignantly, "Young man, you may think of silver in tons, but the Treasury will always think of silver in troy ounces."

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For those wondering like me:

6000 metric tons of silver is approximately 192,904,200 troy ounces, and 6000 US tons of silver is approximately 175,000,000 troy ounces.

There is a US ton? My God...

Yes, many of us Americans wish we would adopt the metric system.

You did. All your (USA) units use metric then are converted to US measurements. The US inch is officially 25.4mm exactly.

https://www.nist.gov/pml/owm/si-units-length

Yup. And more things are SI units every day.

I use them most of time now. We are getting there slowly.

Wrapped in ham to fool the masses.

Lol, sure.

I just made sure I did my homework so I can operate with anyone.

And it was huge. I have few worries.

And an imperial ton, which is different again.

To be perfectly fair, it was a little strange for the metric system to have a "ton" unit in the first place. Much like a foot or a cup, it's one of those units the metric system is trying to replace, but rather than use megagrams or something else perfectly sensible within the system they already created, they added to the confusion by defining yet another "ton" close enough to the historical units of the same name.

it's because "megagram" and "milligram" are a hassle. With the added bonus of mm/MM being used to abbreviate millions, I'm personally very grateful for tonnes.

The SI unit of measure is the Kilogram, not the gram. Therefore they ought to be using the kilokilogram KKg, not the Mg.

Just because the definition is based on 1000 of the base unit doesn't mean the prefixes start being weird.

Not sure what you mean, kg is the base unit. /s

>The SI comprises a coherent system of units of measurement starting with seven base units, which are the second (symbol s, the unit of time), metre (m, length), kilogram (kg, mass), ampere (A, electric current), kelvin (K, thermodynamic temperature), mole (mol, amount of substance), and candela (cd, luminous intensity).

https://en.wikipedia.org/wiki/International_System_of_Units

the SI unit for kilogram is kg and not Kg

Huh. It looks goofy but it would sidestep the overloaded mm problem.

What does it actually mean for the base unit to be the kilogram, as opposed to the gram, now that they're defined in terms of fundamental constants?

It means if you are using SI units "The kilogram is defined by setting the Planck constant h to 6.62607015×10−34 J⋅s (J = kg⋅m2⋅s−2), given the definitions of the metre and the second."

and gram is some random word you made up, with no definition under SI.

https://en.wikipedia.org/wiki/International_System_of_Units

The gram is indeed defined by SI to be 1/1000th of a kilogram, it's not a random word I made up.

There is no logical difference between the definition you gave, and an alternative definition that says "the gram is defined by setting the Planck constant h to 6.62607015×10−31 J⋅s (J = g⋅m2⋅s−2), given the definitions of the metre and the second", and then defining 1 kg = 1000 g. Which is why I'm asking what this distinction actually means, if anything.

It meant something that feels more real when the kilogram was defined as the mass of a physical reference kilogram object in a vault in Paris, but that changed a few years ago.

> gram

Don't you mean a millikilogram (mkg)?

Older people in certain parts of France still use pound ("livre") to mean 500g. Pint ("pinte") for 500ml is more common.

There's the metric tonne 1000kg, the US short ton 2000lbs and the US long ton 2240lbs(1016kg) also known as imperial ton. I started calling the metric tonne a megagram because I got tired of trying to figure out if it was short, long or metric I was dealing with

The bane of all engineers having to do unit conversions and asking clarifying questions around what type of ton/tonne.

When is the long ton ever used, or is it just historical? I've only ever heard of the 2000lb variety my entire life.

This is from a web site that's been around since the Web 1.0 era: https://www.ibiblio.org/units/dictT.html#ton

oh there is a short ton, a long ton, a metric ton. the normal ton in the US is "short ton" which is 2,000 lbs.

https://en.wikipedia.org/wiki/Ton

we also often encounter a "f*ck ton" or even a "metric f*ck ton". these are usually informal units related to the number of things (especially annoying things) rather than strictly weight.

$30.59 per ounce (current)

If anyone else was curious like me, 6000 US tons is 175 million troy ounces.

And worth $5.4 billion dollars at today's prices.

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