Final answer:
The governess's first sleepless night in Chapter I is not detailed in the provided texts. The second sleepless night in Chapter II is caused by unsettling noises and the presence of a vague figure, leading to feelings of horror and alarm.
Step-by-step explanation:
The student has inquired about the causes of the governess's first and second sleepless nights in a literary work. In Chapter I, the governess's first sleepless night is not explicitly described in the given texts. However, sleepless nights in literature are often the result of anxiety, fear, stress, or preoccupation with troubling thoughts, which may be implied given the gothic or suspenseful nature of these narratives. The second sleepless night in Chapter II appears to be linked to supernatural encounters or unsettling events, such as the sound of a faint far-away sound or a whisper just outside the room, leading to nervousness, fear, and horror.