A little later on we learn of a scene where some French soldiers all worked up at the sight of Napoleon leap into a river and all drown while the emperor does not even notice their stupid sacrifice. Here, when Nikolai is in awe of his Emperor we learn how powerful that draw is.
We no longer live in a world where any one thing captivates us as a group – not music, or TV show, or a book brings us together.
(much) Later we learn how Nikolai is quick to use his fists and hit a man who angers him, and this causes tension between him and Marya. And here we see his anger growing in him, how impetuous he can be (much like Natasha, Petya, and his father are in their way). This contrasts to Andrei who is calm and superior and even to Berg who is calm and banal. Tolstoy never falters with these characters.
Mostly this is a family chapter focusing on how the Rostov family reacts to their son’s letter, but it still follows the theme of perception. Implied is that Nikolai carefully crafted the letter for his family and though we don’t read the letter we can deduce what he has and has not told them (the purse incident, for example).
This scene mirrors Petya’s much later.
6000 rubles. that’s a lot even today.