The nautical chart is indispensable to the economic development of maritime nations; the chart can not follow, but must be a pioneer in that development—the survey vessel must precede the merchantman. And, too, hydrography is the fundamental requisite and one of the most important factors in the construction of the nautical chart. Because of the lack of detailed hydrographic surveys over a large part of the coastal waters of the world, early nautical charts were constructed in large part from very incomplete and approximate basic data, generally of a reconnaissance nature. As the economic importance of these areas increased, and as the national consciousness became awakened to the necessity of adequate charts as an important factor in the nation’s development, detailed hydrographic surveys for revised charts were begun, utilizing the means and employing the methods available at the time. These surveys have been followed, in turn, by others . . .