His earnestness could do no harm to anybody.

There was no danger of anyone taking seriously his dream of tropical coal, so what was the use of hurting his feelings?
Thus reasoned men in reputable business offices where he had his entree as a person who came out East with letters of introduction--and modest letters of credit, too--some years before these coal-outcrops began to crop up in his playfully courteous talk.

From the first there was some difficulty in making him out.

He was not a traveller.

A traveller arrives and departs, goes on somewhere.