A Twain item on the Treaty With China appeared almost immediately after he made port in NYC from San Francisco at the end of July, 1868, according to Mark Twain Day By Day. Of course the term "Chinamen" is no longer in acceptable use for males of the ethnicity, as the term "Nigger" is taboo for African-Americans in English. The Chinese had to wait much longer to be accepted as U.S. citizens, as we know.
We almost all agree today that Twain had no intent to demean either in his writings about Asians or Africans who had been brought to America, most as slaves in both cases. I suspect this article and others printed in North California papers led to his decisions to never return to the city where he adopted his Twain handle.
The quote from the Trib, via MTDBD (MTL2:239n1):
"I have seen Chinamen abused and maltreated in all the mean, cowardly ways possible to the invention of a degraded nature, but I never saw a policeman interfere in the matter and I never saw a Chinaman righted in a court of justice for wrongs thus done him."
HISTORY FOOTNOTE: (Most Twain scholars will know these facts, and should read no further)
In the early Spring of 1869, just months after the above was published, the Trans-Continental Railway was linked with the driving of a golden spike near the north shore of the Great Salt Lake.
Chinese men, who had done most of the work on the western stretch, Sacramento to Utah, were not allowed at the Golden Spike Driving Ceremony, 1869.
Again in 1969 a centennial ceremony was set to also exclude recognition of the Chinese part of the work, with a separate ceremony scheduled the next day. Predictably, angry protests resulted in making the 100th an inclusive event. A film was made of the fight, the dancing, and the formal 100th Anniversary ceremony.
FOOTNOTE TO THE FOOTNOTE: The popular story of the reason for bringing Chinese to build eastward from Sacramento was that Irishmen from the great migration, building from Chicago westward, refused to work with dynamite. The "Shanghai'd" Chinese men were not afraid of it, though a good many died because of unsafe work conditions, and no OSHA to keep watch, during blasting through the Sierra Nevada. The barons of the railway (Stanford, Crocker, et al) had promised their remains would be returned to China at company expense, and the workers would also have a free (mandatory) trip home when the work was done. Both promises were unkept.
Later, the "slave ships" were used by Crocker and writer Jack London to bring Eucalyptus seedlings to San Francisco and the East/North Bay counties, where they flourished like weeds and have fueled some bad forest fires in every decade since, including the one that burned the Wolf House of Mr. London and the deadly 1991 Oakland Hills fire.
The Golden Gate National Park and National Recreation Area are gradually removing these illegal, immigrant trees from their acres, as are some of the cities and counties along and near the coast
Richard Reineccius, SF/Oakland