The only way I know of to make ice, as opposed to just storing it, would be to have some sort of compressor that worked on the same principle as modern refrigeration. But it seems unlikely that they had anything like that in Rome - it's been a while, but I'm certain my Roman Civ prof would have mentioned something like that. I recall reading -- somewhere -- that they did have ice in Rome, at least the very rich did. It was actually transported from the Alps. I have no idea where I read this, but my lingering impression is that it was authoritative. Now that I think about it, I wonder ... even with good Roman roads, could a large cart of ice blocks last long enough to make the journey?
Liberals/Evolution BELIEVE they are the conservatives--guardians--saviors--inventors--innovators too...cheats-LIARS-("half wits--idiots")* frauds--charlatans!
*...'subliminal kid' talk!