Accustomed as he was to the varying moods of his remarkable friend, he had never before been met with a reticence so absolute.

It made him think; but for once in his life did not make him loquacious.
Mr.Gryce seemed to be gratified by this, though he made no remark to that effect and continued to preserve his abstracted look and quiet demeanor.

So Sweetwater waited, and while waiting managed to steal a glimpse at the small object to which his professional friend still paid his undivided attention.
It looked like a narrow bit of dingy black cloth--just that and nothing more--a thing as trivial as the band which clips a closed umbrella.

Was it such a band, and would he presently be asked to find the umbrella from which it had fallen or been twisted away?
No.

Umbrellas are not carried about museum buildings.