Cap down SOX experiment

Well this lamp was turned off this morning after 21 hours and 39 minutes!, and the sodium has indeed slowly started to make its way down the tube, however I was surprised it wasn’t by much?
It is a clever bit of lamp engineering though in how Philips processed the inner glass to limit the movement of sodium, even in this ‘extreme’ condition of operation!
You can see that’s quite a big and heavy, (in its liquid from), blob of sodium and still it clung onto its tube throughout its 21 hours!