Remorse extinguished every hope. I had been the author of unalterable evils, and I lived in daily fear lest the monster whom I had created should perpetrate some new wickedness.

In this quote, Victor admits to himself and the reader that he bears some of the blame for the murders the monster has committed. He goes so far as to call himself the "author of unalterable evils," declaring himself responsible for the terrible tragedies of the last few chapters. While he also held himself accountable in Chapter 8 (calling himself the "true murderer" and William and Justine "the first hapless victims to my unhallowed arts"), the fact that he continues to recognize himself as the cause of his own misery proves that his character is undergoing genuine growth.

Sometimes I could cope with the sullen despair that overwhelmed me, but sometimes the whirlwind passions of my soul drove me to seek, by bodily exercise and by change of place, some relief from my intolerable sensations.

In the second half of Chapter 9, Victor explains that in order to escape the despair that haunts him after Justine and William's deaths, he often goes on long hikes through the Alpine valleys and mountains. The magnificence of the natural world soothes him and gives him relief (albeit fleeting) from his unbearable grief; during one journey, he says "The weight upon my spirit was sensibly lightened as I plunged yet deeper in the ravine of Arve." When he immerses himself in nature, he is able to temporarily experience peace, or at least "the greatest consolation that [he] was capable of receiving."

Read more about the theme of Sublime Nature.

The monster: ...I...who am miserable beyond all living things!...You, my creator, detest and spurn me, thy creature, to whom thou art bound by ties only dissoluble by the annihilation of one of us. You purpose to kill me. How dare you sport thus with life? [...]

Victor: [...] You reproach me with your creation, come on, then, that I may extinguish the spark which I so negligently bestowed.

This Chapter 10 exchange takes place between Victor and the monster when they meet at the summit of Montanvert. The monster expresses his acute misery and accuses Victor of, essentially, playing God ("sport[ing] thus with life"), and Victor fires back that if the monster is so unhappy, then Victor will be glad to take the life he "so negligently bestowed" upon him. In a few brief paragraphs, the conversation manages to touch on many of the book's most important themes: parental responsibility, the effects of isolation, and the consequences of ambition.

Everywhere I see bliss, from which I alone am irrevocably excluded. I was benevolent and good; misery made me a fiend. Make me happy, and I shall again be virtuous.

The monster speaks these words to Victor at the end of Chapter 10, before imploring his creator to listen to his tale and then decide what fate the monster deserves. Up to this point, the monster has only been described in horrifying terms: as a demon, a fiend from hell, a wretched devil, an abhorred and grotesque creation. This is the first time the monster is described in a positive way (albeit by himself): we learn that he was once benevolent, good, and even virtuous. This comes as a shock to the reader, who Victor has led to believe that the monster is an irredeemable, vile wretch. The monster's description of himself sets the stage for his own story in Chapter 11 and, for the first time, gives the reader a reason to consider sympathizing with him.  

Read an essay about whether the monster can be considered "good."