Green’s Dictionary of Slang

(orig. US) any automobile; also attrib.

1904		‘Hugh McHugh’ I’m from Missouri 56: I [...] called up a Bubble shop [...] and ordered a motor-car.
1905		‘Hugh McHugh’ Get Next 14: Bunch had just tied his Bubble to a tree at the track and was in the act of giving it a long cool drink of gasolene.
1906		S. Ford Shorty McCabe 288: I sees one of them big bay-windowed bubbles slidin’ past like a train of cars.
1907		‘Hugh McHugh’ Beat It 73: Nix on the Bubble.
1911		S. Ford Torchy 67: Your bubble’s back in the garage bein’ fitted with a new set of hundred-dollar tires.
1918		Wodehouse Piccadilly Jim 209: From the direction of the street, came the roar of a starting automobile... ‘Gee! He’s beat it in my bubble and it was a hired one!’.
1920		Wodehouse Coming of Bill 231: I’ll take you out in the bubble, the automobile, the car, the chug-chug wagon.
1939		in DARE.
1966		Current Sl. I:1 2/2: Gas bubble A Volkswagen.
1972		Hall & Adelman Gentleman of Leisure 15: When you buy a car like mine, it is definitely for attention. I am recognized by the bubble.