"Sir" was applied to all nobles, whether they possessed estates or not.

The brothers were invariably addressed as Sir Felix or Sir Oliver.

It marked, therefore, the low estimation in which the Baron was held when even his own sons spoke of him by that title.
Oliver, though a military man by profession, laughed at Felix's strict view of the guards' duties.

Familiarity with danger, and natural carelessness, had rendered him contemptuous of it.
"There's no risk," said he, "that I can see.

Who could attack us?
The Bushmen would never dream of it; the Romany would be seen coming days beforehand; we are too far from the Lake for the pirates; and as we are not great people, as we might have been, we need dread no private enmity.