You can't be too cautious, but don't be too suspicious.

God bless you, my honest friend.
Go!" And, flinging the door open for his exit, the Doctor saw Israel dart into the entry, vigorously spring down the stairs, and disappear with all celerity across the court into the vaulted way.
The man of wisdom stood mildly motionless a moment, with a look of sagacious, humane meditation on his face, as if pondering upon the chances of the important enterprise: one which, perhaps, might in the sequel affect the weal or woe of nations yet to come.

Then suddenly clapping his hand to his capacious coat-pocket, dragged out a bit of cork with some hen's feathers, and hurrying to his room, took out his knife, and proceeded to whittle away at a shuttlecock of an original scientific construction, which at some prior time he had promised to send to the young Duchess D'Abrantes that very afternoon.
Safely reaching Calais, at night, Israel stepped almost from the diligence into the packet, and, in a few moments, was cutting the water.
As on the diligence he took an outside and plebeian seat, so, with the same secret motive of preserving unsuspected the character assumed, he took a deck passage in the packet.

It coming on to rain violently, he stole down into the forecastle, dimly lit by a solitary swinging lamp, where were two men industriously smoking, and filling the narrow hole with soporific vapors.

These induced strange drowsiness in Israel, and he pondered how best he might indulge it, for a time, without imperilling the precious documents in his custody.
But this pondering in such soporific vapors had the effect of those mathematical devices whereby restless people cipher themselves to sleep.
His languid head fell to his breast.