He had a clean-cut, professional look.

Tom did not take his eyes off the descending column for a second, but he heard Mr.Conne say pleasantly, "Just a minute." He was glad when he was conscious of this fine-looking young American passing on.
So it went.
There were some whom poor Tom might have been inclined to stop by way of precaution for no better reason than that they had a rough-and-ready look--hard fellows.

He was glad--_half_ glad--when Mr.Conne, for reasons of his own, detained one, then another, of these, though they wore no glasses.

And he felt like apologizing to them for his momentary suspicion, as he saw them pause surprised, answer frankly and honestly and pass on.
Then came a young officer, immaculately attired, his leather leggings shining, his uniform fitting him as if he had been moulded into it.

He wore little rimless eye-glasses.