explosives from balloons.
Before the end of the year 1908, one hundred and thirty-five arbitration
treaties had been concluded. The United States was a party to twelve of
these. Most of the treaties bind the signatory powers to submit to the
Hague Tribunal all differences in so far as they do not affect "the
independence, the honor, the vital interests, or the exercise of
sovereignty of the contracting countries, and provided it has been
impossible to obtain an amicable solution by means of direct diplomatic
negotiations or by any other method of conciliation."