2. Envoys and ministers.
3. Ministers resident.
4. Charges-d'affaires.
This fixing of the grades removed friction that had long existed, as states were expected to exchange representatives of equal rank. The United States did( not, however, send abroad agents of the grade of ambassadors till after the Act of Congress of 1 March 1893, authorizing such action on the part of the President.
As freedom of action was essential for the performance of the functions of the diplomatic agent, the principle of inviolability was ex tended not merely to the person of the diplomat but to his suite, family and hotel or official resi dence with all the personnel and equipment which might be necessary or reasonably con venient for the proper performance of his func tions. He was also entitled to certain honors, such as salutes according to his grade. His prerogatives, if an ambassador, extended to the right to ride in a coach with six horses and outriders and to remain covered in the presence of the sovereign if the sovereign did not remove his hat. Other grades were entitled to lesser marks of respect. The establishing of these rules removed the causes of the ancient con tests over rank and dignities and enabled the diplomatic agents to live in harmony and trans act the business of the state, receiving the honors not as personal but as for the states which they represented. Each state in sending its representative and in determining his grade determined his rank at the court to which he was accredited. Minor differences have arisen, but for the most part the controversies as to rank which were common before 1815 have come to an end.
Other problems which were once perplexing in international relations, as for instance, the regulation.and later the suppression of the slave trade have likewise disappeared.
Some have taken new form as the use of private vessels in the time of war after the abolition of privateering, and new problems have arisen, as in the regulation of the use of the air. To meet these changes the interim, tional law development of -the 19th and 20th centuries has tended to become more and more conventional.
The conventional international agreements were at first generally incidental to some other international act as in the agreement fixing the grades of diplomatic agents: The same was true of the Declaration of Paris of 1856 in which it was stated that the plenipotentiaries who signed the Treaty of Paris "considering that maritime law had long been the subject of deplorable disputes . . . cannot better re
spond to the intentions by which their govern. ments are animated, than by seeking to intro duce into international relations fixed principles, in this respect.' They accordingly made' the following solemn declaration; "I. Privateering is and remains abolished: "2. The neutral flag covers enemy's goods, with the ex ception of contraband of war: 3. Neutral goods, with the exception of contraband of war. are not liable to capture under the enemy's flag.
"4. Blockade., in order to be binding. must be effective that is to say. must be maintained by force sufficient really to prevent access to the coast of the enemy." The United States and several other powers did not adhere to this declaration, though its principles were generally recognized. The United States wished in 1856, _as in earlier and later days, to secure the general exemption from capture of private property at sea.
Agreements reached by states assembled for the purpose of formulating what may be called international law gradually became common, It would seem but natural that the destruction of life without advantage to any state would be one of the early matters of attention as a sub ject for a formulated international agreement, Yet the first international agreement relating to this matter to' receive general assent was cony eluded in 1864, and known as the Geneva Con vention for the Amelioratitin of the Condition of Wounded in Armies in the. Field. The neki resentatives of 12 European states stated in the preamble their purpose to be to mitigate "the evils inseparable from war, to suppress useless severities, and to ameliorate the condition of soldiers wounded on the field of battle.) ' It was a long time-for the world to wait fop such legislation. This Geneva Convention of 1864, which provided for the immunity-of the hospital corps, was not immediately 'ratified, however, The United States did net adhere to this vention till 1882, and this was- the only interna4 tional agreement of general -scope and relating to war to which even the United. States became a party before the-end of the 19th century.