She's certainly commoner clay than Rose.

No, I won't say that! It's really nothing but General Triscoe's being an old goose about her that makes her seem so, and it isn't fair." March went down to his coffee in the morning with the delicate duty of telling Kenby that Mrs.Adding was in town.

Kenby seemed to think it quite natural she should wish to see the manoeuvres, and not at all strange that she should come to them with General Triscoe and his daughter.

He asked if March would not go with him to call upon her after breakfast, and as this was in the line of his own instructions from Mrs.
March, he went.
They found Mrs.Adding with the Triscoes, and March saw nothing that was not merely friendly, or at the most fatherly, in the general's behavior toward her.

If Mrs.Adding or Miss Triscoe saw more, they hid it in a guise of sisterly affection for each other.