Cargo in bulk.
Vessels arriving at a port of entry in the United States, laden with coal, salt, railroad iron and other like articles in bulk may proceed to places within that collection district to be specially designated by the Secretary of the Treasury by general regulations or otherwise, under the superintendence of customs officers, at the expense of the parties interested, for the purpose of unlading cargoes of the character before mentioned. (R. S., 2776; June 26, 1884; sec. 29.)