[manifestsilence]

Oh yeah, I'd forgotten how weird smell in particular was. I seem to remember at the time that there were three competing theories for how smells are even perceived or what gives a substance a particular kind of smell, and each only explained a subset of smells.

For the helium leak, is one symptom a high squeaky voice, or is that at already really dangerous concentrations?

[guitarbill]

From what I remember, dizziness, headache, inability to concentrate, etc. You'd notice a big/quick release as the liquid helium boils of quite easily. A slow leak is more dangerous, in which case you might even get used to the higher pitch without noticing.

[fwip]

One symptom of a helium leak is that your iPhone might stop working: https://motherboard.vice.com/en_us/article/gye4aw/why-a-heli...

This happened also to the coworkers of a friend of mi e - occasionally everyone's iPhone in their office would stop working. Android phones still worked fine. Later (after this article was published) they found out there was an MRI machine downstairs.