How does Ethan express his feelings for Mattie physically? How does she react?

From the text:

She looked up at him languidly, as though her lids were weighted with sleep and it cost her an effort to raise them. Her glance fell on his hand, which now completely covered the end of her work and grasped it as if it were a part of herself. He saw a scarcely perceptible tremor cross her face, and without knowing what he did he stooped his head and kissed the bit of stuff in his hold. As his lips rested on it he felt it glide slowly from beneath them, and saw that Mattie had risen and was silently rolling up her work. She fastened it with a pin, and then, finding her thimble and scissors, put them with the roll of stuff into the box covered with fancy paper which he had once brought to her from Bettsbridge.