to reduce malaria to small proportions even in places like Cuba and Panama which in the past have suffered terribly from fever.

This fact was demonstrated by the medical officers of the United States army in connection with the sanitary work done in Cuba following the Spanish-American War. The work done at Havana from 1898 to 1901 by Doctors Reed, Sagaer, Carroll, and Agramonte in demonstrating that the stegomyia was the transmitter of yellow fever, and by Colonel Gorgas who applied the theory to the sanitation of Havana, made it possible for the United States to convert the Canal Zone from a section where yellow fever had long been endemic and violent malarial fevers had been prevalent, into one of the most healthful regions of the world.

Fortunately for the United States and especially for the army of laborers and their families who have lived in the Canal Zone since 1904, the sanitary work at the Isthmus was placed in charge of Colonel Gorgas, the man who, by driving yellow fever out of Havana, had shown his ability to cope with difficult problems of practical sanitation. How Colonel Gorgas, who is now Major General, and Surgeon General of the United States army, did his work at Havana and at Panama has been delightfully told by himself in his book on Sanitation in Panama.

Those who have not personally run the risk of

yellow fever infection can hardly realize how great was the danger from the dread disease at the Isthmus of Panama, and other places where the disease was endemic, before it was known that the mosquito was the agent of infection. In March, 1900, the writer was at Panama with the Isthmian Canal Commission and spent about three weeks inspecting the canal route and the work that had been done by the French Company. He and his wife, who was with him, were so fortunate as to occupy a cottage that was placed at their disposal by the late Colonel J. R. Shaler, then the superintendent of the Panama Rail Road. The cottage was located directly on the Caribbean shore and the refreshing trade winds, blowing day and night, made life most comfortable, and the visit to the Isthmus most enjoyable. There was no special thought of danger from yellow fever. Not long after, however, Colonel Shaler was visited by his three sisters who occupied the same cottage. One after another the three ladies were infected with yellow fever and all died of the disease. Such a tragedy as this helps one to realize what was gained for the people who have lived and worked in the Canal Zone, and for the construction and operation of the canal, by the extermination of yellow fever from the Zone. Indeed, the sanitation work at Panama has benefited the entire world for all time.

When, in 1905, yellow fever had been done away with and the department of sanitation had gotten malarial fevers well under control, the chief obstacle to the economic and rapid progress of the work of construction had been overcome. It was then possible for the Isthmian Canal Commission to secure, maintain, and keep in healthy efficiency the force required in each branch of the work. How the problems of engineering, administration, and construction were worked out by the successive chief engineers-that is, how the canal was built-is described by Brigadier General William L. Sibert and Mr. John F. Stevens in their book, The Construction of the Panama Canal.

This volume on The Panama Canal and Commerce is intended to explain why the canal was built, and to discuss the use of the waterway by the commerce and shipping of the United States and other countries. The commercial services being rendered by the canal are described, and an explanation is given of the schedule of tolls and the tonnage rules in force at the Isthmus. The discussion is addressed to the man engaged in shipping and also to other students of the canal in relation to commerce. The volume is the third in the series of which Sanitation in Panama by General Gorgas and The Construction of the Canal by General Sibert and Mr. Stevens are the first and second volumes.

CHAPTER II

WHY THE CANAL WAS BUILT

The Panama Canal was built to shorten the length and time of voyages made by merchant vessels and war ships between the Atlantic and Pacific oceans. It has been said that, for the people of the United States, the canal is a commercial convenience and a military necessity. Whether this generalization places undue emphasis upon the military value of the canal will be determined by future events; but, for the present, it seems more accurate to say that the Panama Canal has been constructed primarily to remove the chief physical obstacle to the development of the maritime commerce of the United States, and that the naval and military benefits of the canal, important as they are or may become, are to be ranked second in value in comparison with the commercial services of the waterway.

Until the opening of the canal the strip of land forty miles wide separating the two oceans at the Isthmus of Panama compelled vessels voyaging between the two seaboards of the United States, or between any point in the north Atlantic

and any point on the west coast of North or South America, to make a detour around a large continent which reaches 56° south of the equator, and lies to the east not only of the Isthmus of Panama, but also of the greater part of North America. Viewed from the standpoint of the United States, South America should have been named Southeast America. As is shown by Map 1, the line of 80° west longitude which passes through Pittsburgh, Pennsylvania, and skirts the eastern point of Florida, passes through the western part of the Panama Canal Zone, and cuts off only a very small strip of Ecuador and Peru, Point Parina, the most western point of South America, being only a degree and a third west of the line. The broad continent of South America extends eastward to 34° 50' west longitude, the most eastern point of Brazil being thirty-nine degrees east of New York City and fifty-five degrees east of New Orleans. A north and south line touching the Azores passes only 311⁄2 degrees, about 250 miles, east of South America.

Before the Panama Canal was constructed a steamer making a trip from New York to San Francisco had to make 39° of easting and nearly 97° of southing to pass the Straits of Magellan; i. e., the vessel, in order to reach the west coast of the United States, had to round a point eastward of New York, a distance equal to two-thirds of