engaged in business

References in classic literature ?
Then he pressed five hundred roubles into my hand--to buy myself some bonbons, as he phrased it--and wound up by saying that in the country I should grow as fat as a doughnut or a cheese rolled in butter; that at the present moment he was extremely busy; and that, deeply engaged in business though he had been all day, he had snatched the present opportunity of paying me a visit.
Among the day-boys, of whom there were about a hundred and fifty, sons of the local gentry and of the men stationed at the depot, those whose fathers were engaged in business were made to feel the degradation of their state.