I think for the purpose of discussion protégé will do very well for Harriet and Mr. Martin. (:D) It is not important to me that Mr. Knightley sought Harriet’s acquaintance first but that he did what he ought when the opportunity presented itself. Emma did not—she ignored Mr. Martin on Donwell Road. I also don’t think class consciousness prevented him from seeking a closer acquaintance with Harriet rather I think it was personal taste. His confession “I found Harriet more conversable than I expected” (38) suggests he had not found her very conversable. Since it does not seem he ever neglected Harriet I don’t see a reason to fault his taste or manners.

I think there is a similarity in Emma’s and Mr. Knightley’s attitude towards the other’s protégé in that they have differing ideas to the claims of Harriet and Mr. Martin. IMO the difference is that Emma ignores and undervalues Mr. Martin claims while Mr. Knightley has a pretty realistic view of Harriet’s claims. He does not believe Harriet is Mr. Martin’s equal but Emma’s praise of Harriet’s beauty and good nature seem to be well represented in his opinion and further he believes she has the potential to be a valuable woman which may perhaps also agree with Emma’s view of Harriet:

"I cannot rate her beauty as you do," said he; "but she is a pretty little creature, and I am inclined to think very well of her disposition. Her character depends upon those she is with; but in good hands she will turn out a valuable woman." (8)

Mr. Knightley may have met Harriet with the desire to discover whether she is a worthy companion for Emma but I suspect the first reasons he sought an introduction was consideration for Emma, Harriet and social obligation. Rescuing Harriet at the ball from Mr. Elton’s neglect (38) shows he would not choose to be unkind to Harriet by refusing to notice her nor would he choose to be unkind to Emma by refusing to know her friend. I feel whether he needed to discover Harriet’s companionability or not he would have sought the acquaintance because it was the right thing to do. I am not sure if Mr. Knightley spent time conversing with Harriet to determine what kind of friend she could be to Emma or if in socializing and observation of them both he discovered she is the “very worst sort of companion that Emma could possibly have” (5).