LOCK AND DAM SITE, GATUN.
EXCAVATION FOR LOCKS, GATUN.
The purpose, therefore, of the first proposal for piercing the Isthmus was for shortening the distance to the Indies and China. The discovery of the nearer riches of Peru, however, illustrated the fact that the Isthmian barrier has its uses as well as its inconveniences. Porto Bello and Panama were fortified, ships were launched from the latter port for the Peruvian traffic, the treasure was carried across the Isthmus under escort and shipped to Spain. The treasure-ships, indeed, were liable to attack on the Caribbean, but the Isthmian barrier proved an important safeguard to the Peruvian possessions of Spain.
In the next century, the seventeenth, the importance of the Isthmian land route declined, owing to the fact that Spain was no longer able to secure even moderate safety for her ships on the Caribbean. In the present days, when the importance of naval power is so well understood, it is hardly necessary to enlarge upon the significance of this fact, and its bearing upon the problems presented by the Panama route to-day. The project of an Isthmian canal for the purpose of trade between Europe and Asia continued to be agitated, but the inducements were inadequate to overcome the obstacles.
In the middle of the nineteenth century, for the second time, it was the need of improved communication between the east and west of the American Continent which provided a sufficient inducement to improve the Isthmian route.
At this time the Government of the United States were much occupied with projects of trans-Isthmian communication, particularly by canal, not with a view to Transpacific commerce, but with the object of improved communication between the east and west of their own territory.
In 1846 a treaty was made with the State of New Grenada (afterwards Colombia) with a view to providing facilities for transport in the war between the United States and Mexico. In its most important provision it is similar to the present treaty between the United States and the new Republic of Panama, viz., the United States guarantee the sovereignty of the State in question over the Isthmian territory. Hence the Isthmus was thus early constituted a Protectorate of the United States.