Frankenstein Letters, Letter 4:

In the third paragraph of the letter, Walton describes to Margaret an appearance which excited their unqualified wonder.

What is this appearance, and why does it intrigue the men on the ship?

Answer: The answer is:

Appearance "a being which had the shape of a man, but apparently of gigantic stature ... "

Why the crew is intrigued?

The crew believed they were many hundred miles from any land; but this apparition seemed to denote that they were not, in reality, so distant as they had supposed.

Explanation:

"We perceived a low carriage, fixed on a sledge and drawn by dogs, pass on towards the north, at the distance of half a mile; a being which had the shape of a man, but apparently of gigantic stature, sat in the sledge and guided the dogs. We watched the rapid progress of the traveller with our telescopes until he was lost among the distant inequalities of the ice."