From Jerry Thomas (1862)
a fizz is "shorter than a Collins, shaken and strained so there's no ice in the glass."
From Ernest P Rawling (1914)
"...the next in flavor is surely the Fizz--the long drink par excelence. At any time or any place where the tongue and throat are dry; when the spirits are jaded and the body is weary; after a long automobile trip on hot and dusty roads; it is then that the Gin Fizz comes like a cooling breeze from the sea, bringing new life and the zest and joy of living.
"And in the 'morning after the night before,' when the whole world seems gray and lonesome, and every nerve and fibre of the body is throbbing a complaint against the indiscrestion, just press the button and order a Ginn Fizz--"Not too sweet, please!" It comes. Oh, shades of the green oasis in the sandy desert fo life!"