There is a clear middle course between both extremes. Instead of being hung or shot or sent away scot free, a spy might fairly be made a prisoner of war. Suggestions in this sense were made at the Brussels Conference on the Laws of War. The Spanish delegate proposed that the custom of hanging or shooting detected spies should be abolished, and the custom be substituted of interning them as prisoners of war during the continuance of hostilities. The Belgian delegate proposed that in no case should they be put to death without trial; and it was even sought to establish a distinction between the deserts of the really patriotic and the merely mercenary spy. The feeling in fact made itself clearly visible, that an act of which a general might fairly avail himself could not in common justice be regarded as criminal in the agent. Between a general and a spy the common-law rule of principal and agent plainly holds good: ‘He who acts through another acts through himself.’ In a case of espionage either both principal and agent are guilty of a criminal act, or neither is. If the spy as such violates the laws of war, so does the general who employs him; and either deserves the same punishment. Were it not so, a general who should hire a bravo to assassinate an enemy would incur no moral blame, nor could be held to act outside the boundary of lawful and honourable hostilities. In some other respects the Brussels Conference displayed the vagueness of sentiment that prevails about the use of spies in war. It was agreed between all the Powers that no one should be considered as a spy but one who secretly or under false pretences sought to obtain information for the enemy in occupied districts; that military men collecting such information within the zone of hostile operations should not be regarded as spies if it were possible to recognise their military character; and that military men, and even civilians, if their proceedings were open, charged with despatches, should not, if captured, be treated as spies; nor individuals who carried despatches or kept up communications between different parts of an army through the air in balloons. The German delegate proposed, with regard to balloons, that those who sailed in them might be first of all summoned to descend, then fired at if they refused, and if captured be treated as prisoners, not as spies. The rejection of his proposal implies that by the laws of modern war a balloonist is liable to be shot as a spy; so that, from the point of view of personal danger, the service of a balloon becomes doubly heroic. The Brussels Conference settled nothing, owing to the withdrawal of England from that attempt to settle by agreement between the nations the laws that should govern their relations in war-time; but from what was on that occasion agreed to or rejected may be gathered the prevalent practice of European warfare. Is it not then a little remarkable that for the dangerous service of