Watchtower 1902 July 15 The Negro Not A Beast pp. 215-216.
"While it is true that the white race exhibits some qualities of superiority over any other, we are to remember that there are wide differences in the same Caucasian (Semitic and Aryan) family; and also we should remember that some of the qualities which have given this branch of the human family its preeminence in the world are not such as can be pointed to as in all respects admirable. ... The secret of the greater intelligence and aptitude of the Caucasian undoubtedly in great measure is to be attributed to the commingling of blood amongst its various branches; and this was evidently forced in large measure by circumstances under divine control. ... Noah declared, prophetically, that Hams characteristics which had led him to unseemly conduct disrespectful to his father, would be found cropping out later, inherited by his son, and prophetically he foretold that this degeneracy would mark the posterity of Canaan, degrading him, making him servile. We are not able to determine to a certainty that the sons of Ham and Canaan are the negroes; but we consider that general view as probable as any other."

Russel had som great theories about blacks turning into white if they learned the truth, lol...

Watchtower 1904 February 15 pp.52-53
Can the Ethiopian change his skin? What the Ethiopian cannot do for himself God could readily do for him. The difference between the races of men and the differences between their languages have long been arguments against the solidarity of the human family. The doctrine of restitution has also raised the question. How could all men be brought to perfection and which color of skin was the original? The answer is now provided. God can change the Ethiopians skin in his own due time. Prof. H. A. Edwards, Supt. of Schools in Slater, Mo., has written for the public press an elaborate description of how Julius Jackson, of New Frankfurt, Mo., a negro boy of nine years, began to grow white in September, 1901, and is now fully nine-tenths white. He assures us that this is no whitish skin disease; but that the new white skin is as healthy as that of any white boy, and that the changed boy has never been sick and never has taken medicines

WHen showing the PhotoDrama of Creation colored people were segregated and put on the balcony, so they wouldn't disturb the pure white audience:

Watchtower 1914 Apr 1 p.105 "WE might have anticipated that many colored people would be deeply interested in THE PHOTO-DRAMA OF CREATION. But it did not impress itself upon us until gradually their number increased to about twenty-five per cent of the whole audience. Of course, we were glad to see them, glad that they were interested in the DRAMA. We had the same feeling respecting them as others; but it was quickly discerned that it was not a case of feeling, but that, whereas the colored people of New York City are about five per cent of the population, in our audiences they are about twenty-five per cent and the number increasing. What shall we do? As the attendance of the colored people would increase, proportionately the number of the whites would decrease; for explain it how we will, a majority of whites prefer not to intermingle closely with other races. Recognizing that it meant either the success or the failure of the enterprise of the DRAMA as respects the whites, we have been compelled to assign the colored friends to the gallery, which, however, is just as good for seeing and hearing as any other part of The Temple. Some were offended at this arrangement.

Golden Age 1929 Jul 24 p.702 (Now Awake!)
"Is there anything in the Bible that reveals the origin of the Negro? It is generally believed that the curse which Noah pronounced upon Canaan was the origin of the Black race. Certain it is that when Noah said, 'Cursed be Canaan, a servant of servants shall he be unto his brethren,' he pictured the future of the Colored race. They have been and are a race of servants.. There is no servant in the world as good as a good Colored servant, and the joy that he gets from rendering faithful service is one of the purest joys there is in the world."

Someone showed me this article from the watchtower written by a missionary serving in South Africa in the 1950s.

Watchtower W54 6/1 - The mind of the African.
''The New World organization, thanks to Jehovah, is provided with the “weapons of the light” and has the only successful program for renovating the mind and clothing its subjects with a changed personality conformed to Christ Jesus, the Head. Secular education, admittedly, has failed to inculcate love. False religion, likewise, has failed to teach and follow true Christian principles, and the African has not been deeply impressed by what is so often hypocritical and partial. True religion, which does not make distinctions but which operates on the basis of love and abounds in the “fruitage of the spirit,” wins his approval, respect, sympathy and co-operation. The African mind has one obvious characteristic: it is childish and imitative. The visits of African circuit servants are doing much to set a good example. What could help much would be for African brothers to mix socially with the European brothers. This is ruled out by the strict segregation arrangements in South Africa.''