I think you need to look at Clemens' Western Years when it comes to comparing his attitudes toward black slaves to Native Americans in the 1860s. The black slaves were enslaved. The Native Americans were killing people. In Carson City one of his rooming house friends, Will Wagner, had been shot at by Paiutes. In Aurora, he was involved with management of weapons in use by the Army in mortal combat with Southern Paiutes in Owens Valley. (The local sheriff was among those killed.) So his attitude toward those two groups was shaped by different circumstances.  

    On Thursday, December 1, 2016 11:20 PM, Jon Kerr <[log in to unmask]> wrote:
 

 Hi,

Curious if anyone knows of any good biographical information (or even good
fiction) on the real Injun Joe figure, Joe Douglass. I've heard several
brief accounts of his difficult life and how he may have impacted young Sam
Clemens. But curious to know more, and hopefully better understand how
Twain could use such racist images of Native Americans even while clearly
developing a consciousness about black slaves and America's grim history.

Thanks for any references,
Jon Kerr