Marsden doesn't rape Diana, but he does subject her to sexual harassment, as he does to a number of the girls at the factory, including Lyddie. He tries to make a move on Brigid, but when he does, Lyddie hits him over the head with a fire bucket. For this act of bravery, Lyddie is hauled before the management and accused of being a troublemaker, when it's Marsden who's the real villain of the peace. Despite her protestations of innocence, Lyddie ends up being fired. But at least she did the right thing in confronting a notorious sexual predator. This whole unfortunate episode illustrates the appalling conditions that the factory girls are forced to endure and how even productive workers, like Lyddie, can be treated unjustly.

Mr. Marsden can be accused of sexual harrassment because he puts his arms around Lyddie when he makes her stay late after work, but he does not rape her. Something has happened to Diana because she is pregnant and has to leave the factory. Lyddie "just knows" the father has to be the doctor, but all Diana says is that there's a wife in Concord. We could speculate that it is Marsden because Lyddie warns him that she has written a letter to his wife to tell her what really goes on after hours at the factory and that she will mail it if he fires Brigid.

The best way to find out what happens in a story is to read it! I hope this helps.