To the tutor especially, tied as he was to the scene of the tragedy, those three weeks were a period of torture.

He urged Dr Brandram to go over to Paris to make inquiries; but the Doctor, after a fortnight of fruitless search, returned empty-handed.
Mr Armstrong thereupon resolved at all hazards to quit his post and go himself.

He knew something of Paris.

He had old associations with the city, and once, as the reader has heard, possessed acquaintances there.
If any one could find the boy, he thought he could; and with such trusty substitutes as the Doctor and Mr Headland, who remained at Yeld, to leave behind, he felt that he might, nay rather that he must, venture on the journey.
It was on the morning of his departure, as he was waiting for the trap to carry him to the station, that Roger's telegram was put in his hand:-- "Come--have been ill--better now--Hotel Soult--no news." Twenty-four hours later the tutor was at his pupil's side, with a heavy weight lifted from his heart, and resolved, come what would, not to quit his post till he had the truant safe back at Maxfield.
The news he brought with him served to drive from Roger's mind all thoughts of continuing his sojourn a day longer than was necessary to recover his strength.
"It seems pretty certain," said he, "that my brother, when he left here, returned to England, and probably went to sea very soon after.

There is no object in staying here.