I was stewing onions in milk last evening in readiness for poaching smoked hake later.

While I was peeling the potatoes for the mash, on which I planned to serve the hake, the milk boiled over.

At this moment of annoyance with myself - the smell of burning milk is simply not an appetizer, is it? - my eye lit upon this little glass object.

It has all the characteristics of an ash-tray - by this I mean that it is a small, slightly-dished object with indentations in its rim sufficient to rest a cigarette and, indeed, that is the purpose to which it is now put when smokers are about.

But.................

In the early 1960's I spent a year living in Libya with my parents.

And during that time, early every morning, a man driving a scooter with a mini-tanker containing goat's milk trailing behind him, arrived to deliver our order.

And, once in our kitchen, the milk was poured into a saucepan in which the little glass object sat on the bottom, dished-side down.

It allowed my mother (or her cook) to boil the milk quite fast without it boiling-over and it made a memorable 'chattering' sound on the bottom of the pan. Evidently the action of the heated milk escaping from beneath the little glass object via the indentations, created sufficient turbulence in the pan to prevent the milk boiling over.

So, this evening having spotted it, I dropped it into my pan of milk and onions and while I topped-and-tailed the green beens that were to accompany the meal, the milk and onions simmered away without causing me further annoyance, as the little glass object, performed its task and chattered away to me!

I have never seen or heard of a little glass object such as this before or since.

Did my mother have it in her back pocket, as it were, since her times in Africa in the 1930's or was it a standard piece of kitchen equipment before M. Pasteur?