In Chapter 18, Charlie comes to visit Lyddie. He has been sent on the train by the Phinneys, and he has "good news." Not only have the Phinneys taken him on as an apprentice, they also want to adopt him. This cuts Lyddie because she has worked hard, keeping her family in mind through all her difficult days of toil. Her sole desire has been to reunite her family back on the family farm, and she has been relentless in pursuit of that goal.
But that is not the end of Charlie's news. Mrs. Phinney, he says, "craves a daughter as well." She wants Charlie to bring Rachel back, and she will raise her as her own daughter. Lyddie feels as if she is losing all she has left. She feels unable to let Rachel go, but at the same time, she knows she must let Rachel have this chance for a better life. In fact, it will probably mean saving Rachel's life. She has developed a cough, and if she stays in Lowell, she might die from respiratory problems.
In the morning, Lyddie wakes Rachel and tells her she'll be going to visit Charlie. Rachel "was as excited as if she could really remember him." This is the point at which "Lyddie brushed away a cobweb of envy." It is to Lyddie's great credit that the envy is as tenuous as a cobweb. She has much to be envious of--her younger brother and sister are to be given a life of relative ease when she is the one who has slaved and worried for them for the last years. But what she seems to be envious of here is Rachel's emotional attachment to Charlie. Lyddie has grown to love Rachel deeply, and knowing she is going to lose her, she envies the love that Charlie will receive from their sister. She had previously wondered, "Will she ever know how much I loved her?" Her strong attachment to Rachel causes her to envy the love Rachel is ready to give to Charlie--but Lyddie brushes that envy away because her love is stronger than her envy. She is doing what is best for Rachel, despite the emotional pain it causes her.
At the start of Chapter 18, Charlie has come to visit Lyddie. He tells Lyddie that he has a very good life living with the Phinneys. He gets to go to school and live in a house with a mother and father of sorts. He gets to be "normal," and he seems quite happy. Additionally, the Phinneys would like to take Rachel on as their daughter, too. The entire situation makes Lyddie feel jealous, because she has been working her fingers to the bone to try and scrape up enough money to keep the farm and pay off all of the family debt. She's envious because she feels that she is doing all of the work and Charlie is the one getting the good life.
Lyddie doesn't do anything with those feelings, though. She quietly swallows her thoughts and allows Rachel to be taken back to the country with Charlie. The feelings of jealously do not last long, but they are replaced with all around depression. At the beginning of Chapter 19, the reader sees Lyddie struggling to find a purpose for herself at all.
My heart is heavy, she thought. It’s not just a saying. It is what is— heavy, a great stone lodged in my breast, pressing down my whole being. How can I even stand straight and look out upon the world? I am doubled over into myself and, for all the weight, find only emptiness.