It's true that a solid can't boil. However, by "boiling point of stuff St at pressure P", I mean the lowest temperature at which St can be a gas under the pressure P. With this definition of "boiling point", item (4.) is not only meaningful, but often happens. It's called "sublimation", and it's what happens when a solid becomes a gas at the solid/gas boundary on the phase diagram below the triple point. Likewise, "boiling" refers to a liquid becoming a gas at the liquid/gas boundary in the phase diagram, which is equivalent to your definition. "Evaporation" refers to a liquid turning gaseous within the liquid region of the phase diagram. And what do you call a solid becoming a gas in the solid region of the phase diagram?
Because I had been given no convincing justification. By now, oðers have given me such justifications, so I temporarily keep my use of Þorn and Ðat on these forums down.
That statement is the one which is untrue.
Indeed, but that doesn't make them not English. Examples of letters which aren't English are Arabic 7aaɂ ('ح'), Greek Þeta ('Θ'/'θ'), and German 'Ö'/'ö'.
It says that those are the current letters. But it does very much list That and Thorn as English letters, albeit archaic ones. In science, one has to be precise 🙂.
