in brown study

Inside the entrance I found an attendant sitting at a table absorbed in reading, who rose and inquired my business, and upon my statement that I desired to see Mr Breakwater, Esq., on urgent business, courteously directed me up a marble staircase, at the top of which was a second attendant, also engaged in brown study—for the attendants appear to be laudably addicted to the cultivation of their minds.

Block after block of New York's side-streets are sunk thus in brown study.

For a long time the doctor sat in brown study.