Though fraud in all other actions be odious, yet in matters of war it is laudable and glorious, and he who overcomes his enemies by stratagem is as much to be praised as he who overcomes them by force.
As for the virtuous poor, one can pity them, of course, but one cannot possibly admire them. They have made private terms with the enemy, and sold their birthright for very bad pottage. They must also be extraordinarily stupid.
Steam was till the other day the devil which we dreaded. Every pot made by any human potter or brazier had a hole in its cover, to let off the enemy, lest he should lift pot and roof and carry the house away.
The end and aim of spying in all its five varieties is knowledge of the enemy; and this knowledge can only be derived, in the first instance, from the converted spy. Hence it is essential that the converted spy be treated with the utmost liberality.