What was Arthur working on before he was killed?

Arthur was working on a manuscript that called for better treatment of South Africa's blacks. Here is an excerpt,

"It is not permissible to mine any gold, or manufacture any product, or cultivate any land, if such...depend(s) for (its) success on a policy of keeping labour poor. It is not permissible to add to one's possessions if these things can only be done at the cost of other men."