[813] Although—see above, §§ [173]-174—prevention of carriage of contraband is a means of sea warfare against the enemy, it chiefly concerns neutral commerce and is, therefore, more conveniently treated with neutrality.
[814] See Grotius, III. c. I, § 5:—"Sunt res quae in bello tantum usum habent, ut arma: sunt quae in bello nullum habent usum, ut quae voluptati inserviunt: sunt quae et in bello et extra bellum usum habent, ut pecuniae, commeatus, naves, et quae navibus adsunt.... In tertio illo genere usus ancipitis, distinguendus erit belli status...."
[815] See Bynkershoek, Quaest. jur. publici. I. c. X.
It is by the Declaration of London that the Powers have, for the first time in history, come to an agreement concerning what articles are contraband. The distinction which Grotius made between three classes of goods, while still recognised, has been merged by the Declaration of London into the distinction between articles of absolute contraband, articles of conditional contraband, and such articles as may under no circumstances or conditions be considered contraband. This Declaration, moreover, has put the whole matter of contraband upon a new basis, since the Powers have by articles 22 to 44 agreed upon a common code of rules concerning contraband.
Absolute and conditional Contraband, and free Articles.
§ 392. Apart from the distinction between articles which can be made use of only in war and those of ancipitous use, two different classes of contraband must be distinguished.
There are, firstly, articles which by their very character are destined to be made use of in war. In this class are to be reckoned not only arms and ammunition, but also such articles of ancipitous use as military stores, naval stores, and the like. They are termed absolute contraband.
There are, secondly, articles which by their very character are not destined to be made use of in war, but which under certain circumstances and conditions can be of the greatest use to a belligerent for the continuation of the war. To this class belong, for instance, provisions, coal, gold, and silver. These articles are termed conditional or relative contraband.
Although hitherto not all the States have made this distinction, nevertheless they did make a distinction in so far as they varied the list of articles which they declared contraband in their different wars; certain articles, as arms and ammunition, have always been on the list, whilst other articles were only considered contraband when the circumstances of a particular war made it necessary. The majority of writers have always approved of the distinction between absolute and conditional contraband, although several insisted that arms and ammunition only and exclusively could be recognised as contraband, and that conditional contraband did not exist.[816] The distinction would seem to have been important not only regarding the question whether or no an article was contraband, but also regarding the consequences of carrying contraband.[817]
[816] See, for instance, Hautefeuille, II. p. 157, and Kleen, I. § 90.