What do “armful” and “sweep” mean in this conversation?
I watched an old movie released in 1933, and there is a conversation I feel confused about.

Jimmy: Do you want me to give you a word picture of what's going on in that man's mind when he's talking to you about your book?
Mary: Yes.
Jimmy: It's as searching as Huxley. Hm. Hm. What a lovely armful. It has all the sweep of the elder Dumont. Ah. Hm. What a charming interlude I'm going to have with this girl.
Mary: You're testing an old friendship very hard, Jimmie.

I cannot understand what "armful" and "sweep" mean in Jimmy's words. I know it is a very old movie so it may be hard for the modern audience to understand, but I'm wondering if anyone can understand it. Thanks in advance.

Question

What do “armful” and “sweep” mean in this conversation?
I watched an old movie released in 1933, and there is a conversation I feel confused about.

Jimmy: Do you want me to give you a word picture of what's going on in that man's mind when he's talking to you about your book?
Mary: Yes.
Jimmy: It's as searching as Huxley. Hm. Hm. What a lovely armful. It has all the sweep of the elder Dumont. Ah. Hm. What a charming interlude I'm going to have with this girl.
Mary: You're testing an old friendship very hard, Jimmie.

I cannot understand what "armful" and "sweep" mean in Jimmy's words. I know it is a very old movie so it may be hard for the modern audience to understand, but I'm wondering if anyone can understand it. Thanks in advance.

Answer

This is a guess without knowing the film in question.

"armful" could mean jimmy his imagining holding the girl in his arms. "a lovely armful" 
"sweep" may mean this
NOUN many definitions for sweep including this one
a long, swift curving movement.
"a grandiose sweep of his hand"

often used to describe the shape and contour of something a piece of furniture, sofa etc or in this case possibly the shape of the attractive lady.

Elder Dumont I am uncertain about.

Answer

I think Jimmy is talking about "that man" and Imagining what "that man" is thinking while "that man" is taking to Mary.
So you go from a statement made by "that man" followed by "hm" then what that man is thinking.
So the statements don't really matter - huxley and Dumont are irrelevant. What that man is thinking is: Mary is an armful i.e. imagining how good she would feel in his arms. and ... I am going to have this girl - probably get Mary into bed with him.

Sweep doesn't matter but it presumably refers to literary breadth of Dumont - presumably an author.