What is Rebecca Harding Davis's conception of an artist?

Rebecca Harding Davis's conception of an artist is that an artist is someone who can see beauty even when their situation doesn't have much beauty to be seen; that artistic talent and vision, however, can make a person desperate to live a beautiful life they can imagine. If that's impossible, the desperation can lead to the artist's downfall.
When the visitors to the iron mill see Hugh's statue, they love it. They ask him about it and he says that the sculpture is hungry for something other than food. She's hungry to live a better life; she's hungry for experience. His art mirrors his soul because he's hungry for the same things. Harding Davis shows that Hugh can see a life outside the iron mill even if he isn't sure how to capture it for himself.
This desire and longing expressed so beautifully doesn't allow Hugh to survive. After his cousin steals money from the visitors, he decides against returning it because he wants it to allow them to have a better life. It doesn't. He's convicted of the crime and sent to prison for nineteen years. Ultimately, he kills himself there because he can't stand the sorrow and longing for a better life—without any way of getting there.

Davis gives the reader a dreary view of the lives of these people. They work slavishly in the iron mills, which are large tents under which vats of boiling metal bubble and release unbearable heat. The skies are gray with smoke and smog. The Wolf family lives in two basement rooms in a house filled with five other families. Even though they work very hard, there is little money and there are absolutely no frills.
Despite this depressing life, Hugh Wolfe is an artist. He has an artist's eye. He sculpts beauty from many elements. Davis refers to Deb, the cousin of Wolfe, as she writes,

Perhaps, if she had possessed an artist's eye, the picturesque oddity of the scene might have made her step stagger less, and the path seem shorter; but to her the mills were only “summat deilish to look at by night."

Hugh gains strength from his artist's eye, even though he is unaware of it. He only sculpts because he enjoys doing something other than working and sleeping—the only other two things he does daily.