Green’s Dictionary of Slang

(Aus.) a Chinese immigrant to Australia, or the United States.

1880		Bulletin (Sydney) 18 Sept. 4/4: Garrard, the Sydney ‘labour agitator’ [...] recently said at a public meeting on the ‘yellow agony’ question [...] ‘They shan’t marry my daughter.’ (Applause). It is alleged that a Mongolian who happened to be in the crowd muttered, ‘Nobody asked youy, sir, to let ’em’.
1892		Democratic Messenger (Eureka, KS) 17 June 2/5: Opium does much toward reconciling the Mongolian to a life bereft of [...] female company.
1902		Bulletin (Sydney) 25 Oct. 35/2: He couldn’t remember his Chinaman’s face, and didn’t know him from Adam. Out of the 300,000,000 Mongols he plugged one at a venture, and plugged the right one.
1907		S.E. White Arizona Nights III 250: Just then Sang returned with the broom [...] The rustling of papers aroused Señor Johnson from his reverie. At once he exploded. ‘Get out of here, you debased Mongolian,’ he shouted.
1910		Bulletin (Sydney) 18 Aug. 14/2: I can speak feelingly, because I know to my sorrow the habits of the Mongolian. Crush at one time kept an hotel at Brock’s Creek, where there is a Chow-town – a reeking abomination of foul-smelling heathen, opium, blackfellow and decaying matter.