So, I've seen this in a lot of figures of speech and it's always confused me, but I can't think of any other examples besides this one from "Une Autre Étude de Femme" by Balzac:
"Cette question venait de lui être adressée dans une intention évidemment philosophique par un homme d’esprit et d’observation qu’il avait nommé préfet, qui fut longtemps journaliste, et qui l’admirait sans mêler à son admiration ce filet de critique vinaigrée avec lequel, à Paris, un homme supérieur s’excuse d’en admirer un autre."
My question is: what is "en" doing in this context? I really have no idea. As for a translation, I think it's pretty obvious:
"This question was just being addressed to him, with an intention obviously philosophical, by a man of spirit and observation whom he had named préfet, who had long been a journalist, and whom he admired without mixing into his admiration this morsel of bitter critique with which, in Paris, a superior man excuses himself from admiring another."
(I'm sure I could produce a more graceful translation, but it's currently 4 in the morning, so that'll have to wait.)
Any clarification would be much appreciated. Merci d'avance!