It was not until the eighteenth century, with its general tendencies to mitigate the cruel practices of warfare, that matters changed for the better. The conviction in time became general that captivity should only be the means of preventing prisoners from returning to their corps and taking up arms again, and should, as a matter of principle, be distinguished from imprisonment as a punishment for crimes. The Treaty of Friendship[257] concluded in 1785 between Prussia and the United States of America was probably the first to stipulate (article 24) the proper treatment of prisoners of war, prohibiting confinement in convict prisons and the use of irons, and insisting upon their confinement in a healthy place, where they may have exercise, and where they may be kept and fed as troops. During the nineteenth century the principle that prisoners of war should be treated by their captor in a manner analogous to that meted out to his own troops became generally recognised, and the Hague Regulations have now, by articles 4 to 20, enacted exhaustive rules regarding captivity. [Footnote 257: See Martens, _N.R._ IV. p. 37.] [Sidenote: Treatment of Prisoners of War.] § 126. According to articles 4-7 and 16-19 of the Hague Regulations prisoners of war are not in the power of the individuals or corps who capture them, but in the power of the Government of the captor. They must be humanely treated. All their personal belongings remain their property, with the exception of arms, horses, and military papers, which are booty;[258] and in practice[259] personal belongings are understood to include military uniform, clothing, and kit required for personal use, although technically they are Government property. They may only be imprisoned as an unavoidable matter of safety, and only while the circumstances which necessitate the measure continue to exist. They may, therefore, be detained in a town, fortress, camp, or any other locality, and they may be bound not to go beyond a certain fixed boundary. But they may not be kept in convict prisons. Except in the case of officers, their labour may be utilised by the Government according to their rank and aptitude, but their tasks must not be excessive and must have nothing to do with military operations. Work done by them for the State must be paid for in accordance with tariffs in force for soldiers of the national army employed on similar tasks, or, in case there are no such tariffs in force, at rates proportional to the work executed. But prisoners of war may also be authorised to work for other branches of the public service or for private persons under conditions of employment to be settled by the military authorities, and they may likewise be authorised to work on their own account. All wages they receive go towards improving their position, and a balance must be paid to them at the time of their release, after deducting the cost of their maintenance. But whether they earn wages or not, the Government is bound