perspicuity

[…]whether through the first officer's want of perspicuity or my own stupidity, I was not a bit the wiser for the explanation.

“Well,” I answered, at first with uncertainty, then with inspiration, “he would do splendidly to lead your cotillon, if you think of having one.” ¶ “So you do not dance, Mr. Crocker?” ¶ I was somewhat set back by her perspicuity.

It must have been on some such day of harsh sunlight, the incisive February brightness that gives perspicuity without warmth.