brown study

"There's just one thing I'd like to ask, if you don't mind," said Cynthia, coming suddenly out of a brown study.

Dale made his deductions, after which he stood in a brown study beside his horse, waiting for John.

Then with a glance of inquiry at his Captain, who had fallen into a brown study, "Rear rank, take open order!"

"I've never heard him spoken of in that way before," said Eleanor, speaking as if she were in a brown study.

Jim did not pursue the conversation further, but went down very deep into a brown study.