To find the specific phase characteristic of a lighthouse on a sound of the United States, you would use the ___

The Light List is the most appropriate resource to find the specific phase characteristic of a lighthouse. This publication provides vital information about various aids to navigation, including lighthouses, buoys, and beacons. Each entry typically includes the light's color, rhythm, and geographic details, which are essential for mariners to identify and understand how to interpret the signals emitted by these lights.

The American Practical Navigator serves as a comprehensive guide for navigation at sea and covers a wide range of topics, but it does not focus specifically on the detailed characteristics of aids to navigation like the Light List does.

The Nautical Chart Catalog provides information on available nautical charts and their content, while the U.S. Coast Pilot offers detailed shoreline descriptions and navigation guidance. Although these resources are valuable for navigational purposes, they do not concentrate on the specific phase characteristics of lighthouses, making the Light List the most directly relevant tool for this inquiry.