The dentist took them up, one by one, and deliberately examined them.

They were all business letters, and most of them bore country post-marks.

But there was one which had been, in the first instance, posted from London and this letter Mr.Sheldon examined with especial attention.
It was a big, official-looking document, and embossed upon the adhesive envelope appeared the crest and motto of the Alliance Insurance Office.
"I wonder whether that's all square," thought Mr.Sheldon, as he turned the envelope about in his hands, staring at it absently.

"I ought to make sure of that.

The London postmark is nearly three weeks old." He pondered for some moments, and then went to the cupboard in which he kept the materials wherewith to replenish or to make a fire.