Use of 「ぬ」 as a sentence ending in literature


I am reading a Meiji era novel and I frequently sentences that have a verb and
then end in ぬ for example:

> 二階なる一室を下りて主人夫婦が足投げだして涼みいし縁先に来たり **ぬ** 。

or

> 教師は筆おきて読みかえし **ぬ** 。

Can someone help me with this? I know that ぬ can be a variant or hold the same
function as ーず [per here [Conjugation of negative auxiliary
〜ぬ](https://japanese.stackexchange.com/questions/12225/conjugation-of-
negative-auxiliary-%E3%81%AC\]) but I don't see how that would work in these
sentences.

