- Claudius Ptolemaeus (Greek: Κλαύδιος Πτολεμαῖος; c. 100 – c. 170), known in English as Ptolemy, was an ancient Greek geographer, astronomer, and astrologer who probably lived and worked in Alexandria, off the coast of Egypt.
- Vacuum tube (Wikipedia)
A vacuum tube, electron tube, thermionic valve (British usage), or tube (North America) is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. It takes the form of an evacuated tubular envelope of glass or sometimes metal containing electrodes connected to external connection pins.
I know that I am mortal by nature and ephemeral, but when I trace at my pleasure the windings to and fro of the heavenly bodies, I no longer touch earth with my feet. I stand in the presence of Zeus himself and take my fill of ambrosia.
Epigram in some manuscripts of Almagest