To the diplomatic officers of the United States:

Gentlemen: I inclose herewith two copies of Treasury Department Circular No. 230 of June 27, 1911, containing “Rules to Prevent Collisions of Vessels.” In the left-hand column are printed the revised international rules, and in the right-hand column the rules for the navigation of rivers, harbors, and inland waters of the United States navigable by seagoing vessels.

One copy of the circular you will communicate to the Government to which you are accredited, inviting its attention particularly to pages 1517, on which are printed the lines of demarcation within which, after July 31, 1911, the inland rules of the right-hand column are applicable (except on the Red River of the North and rivers flowing into the Gulf of Mexico and their tributaries) and also the lines of demarcation of inland waters of the United States bordering on the Gulf of Mexico, where the pilot rules for western rivers apply.

I am, etc.,

P. C. Knox.