It is a shocking habit - destructive to the logical faculty.
What seems strange to you is only so because you do not follow my train of thought or observe the small facts upon which large inferences may depend.
For example, I began by stating that your brother was careless.
When you observe the lower part of that watch-case you notice that it is not only dinted in two places but it is cut and marked all over from the habit of keeping other hard objects, such as coins or keys, in the same pocket.
Surely it is no great feat to assume that a man who treats a fifty-guinea watch so cavalierly must be a careless man.
Neither is it a very far-fetched inference that a man who inherits one article of such value is pretty well provided for in other respects."
I nodded to show that I followed his reasoning.
"It is very customary for pawnbrokers in England, when they take a watch, to scratch the numbers of the ticket with a pinpoint upon the inside of the case.
It is more handy than a label as there is no risk of the number being lost or transposed.
There are no less than four such numbers visible to my lens on the inside of this case.