1st. Men considered of importance and in high situations, who, through avarice or meanness, yield to corruption. It belongs, however, to the Government of a country to employ such spies, and it is believed that Russia especially has, at this moment, many of them engaged in various countries, and in various ways. 2nd. Men supposed to be respectable in character, priests and intriguing women (I here adopt the words of a French writer), to be almost always found in countries in which war may be carried on; who, through a good use of part of the money, which it may be contrived to remit to them, can procure sometimes valuable information; but the best of such spies are usually found amongst those mentioned, and who are the least liable to raise suspicion. 3rd. Individuals admitted in various ways into the enemy's army--such as servants to general and other officers, sellers of spirits, provisions, and many trifling articles required by soldiers; and some men may through them be induced to desert at particular moments, especially when any important movements are about to take place. Such people can repeat the conversations they may have listened to; they can say pretty correctly where the enemy is in force; what direction he is moving in, as well as what places are occupied by his detachments; but this is generally all that can be looked for from them, their communications being frequently too confused and uncertain to be much relied upon. But some men, for money, as I know from experience, can be found (indeed they offer themselves) who would perform acts that would scarcely be believed, were I to state them. 4th. Intelligent peasants of the country, of whom there are always plenty to be found; but a good many of them should be sent out at one time, under the pretence of selling various articles in the enemy's camp, or cantonments; also to the detachments on his flanks, and lines of communication and operation. Such men should not, however, be employed at any great distance from their homes, as they soon become ignorant of the country and roads. 5th. Good information can often be obtained from prisoners of war of all ranks, if prudently and judiciously questioned by an officer, such as I suppose the head of the police would be; and correct intelligence was even sometimes, to my knowledge, pumped out of our single-minded officers at the out-posts, by the French, during the Peninsular war.