How successfully do Walton's letters introduce the central themes and concerns of the novel "Frankenstein" by Mary Shelley?

Walton is a sailor looking for a paradise. He believes that it exists on the north pole, even though most people would strongly disagree with this hypothesis. There are many similarities between his character and that of Victor Frankenstein, helping introduce the central themes and concerns to the novel. Walton's letters to his sister are the frame of the story. Even the main part of the story is written by Walton and sent to his sister. The first letter is written in December and is sent from St. Petersburgh. Here, we find out about Walton's journey and goal. Walton describes the paradise that he imagines to be
Walton starts by saying that he is safe, although the vessel is endangered by the poor weather conditions. This natural border of weather can also be perceived as a metaphor for ethical borders. If Walton is passing the natural borders of weather conditions and ice, will Frankenstein be just as determined to pass the ethical border and pretend to be God, by defeating death and creating life? In this letter, Walton is highly motivated to complete his expedition and once again fails to see why this journey is a dangerous idea. This letter is ended very romantically, “Heaven bless my beloved sister!”, reinforcing the idea of Walton being a romantic. This letter acquaints the reader with the idea of crossing boundaries, both physically and metaphorically, and, similarly to the other letters, Walton's, and hence Frankenstein's, ambition is presented with negative connotations. The fourth, and last letter of the opening, is written in August, and correspondingly to the third, the location is unknown. Walton starts out by building up the tension. This is done by him telling his sister that a strange incident occurred, without directly saying what it was. The first sentence of this letter is “So strange an incident has happened to us that I cannot forbear recording it”. The fact that Walton's vessel is stuck in ice at this point, can be interpreted metaphorically. It could be a symbol for being trapped in