feet in length, 54 feet beam, and 35 feet deep; drawing 22 to 23 feet of water, and containing 3,500,000 board feet of logs. Log rafts have also at times been transported on the Great Lakes. Their dependence upon favorable weather conditions, however, and the constant danger of loss have prevented log rafts from coming into general use in deep-water navigation.

REFERENCES

ALLEN, H. Gas and Oil Engines (a treatise on the design, construction, and working of internal-combustion engines. Manchester, 1907).

Atlantic Deeper Waterways Association. Report of Committee on Traffic of Proposed Intra-Coastal Canal Connecting New York and Delaware Bays (1911).

CHALKLEY, A. P. Diesel Engines for Land and Marine Work (London, 1912).

Diefendorf, H. G. The Gasoline Engine, Marine and Stationary (1912).

DIESEL, R. "The Present Status of the Diesel Engine in Europe, and a Few Reminiscences of the Pioneer Work in America"

(a lecture, St. Louis, 1912).

JOHNSON, E. R. Measurement of Vessels for the Panama Canal, chap. x; also bibliography, pp. 220-21 (1913).

United States (Bureau of Corporations). Transportation by Water in the United States, I, chap. ii (1909).

(Bureau of Mines [R. H. Fernald]). "Status of the Gas Producer and of the Internal-Combustion Engine in the Utilization of Fuels" (Technical Paper No. 9, 1912). -(Bureau of Mines). "The Commercial Trend of the Producer-Gas Power Plant in the United States" (Bulletin No. 55, 1913).

(Bureau of Navigation). Report of the Commissioner of Navigation (annual).

See also current files of International Marine Engineering; the Marine Review; The Engineer; Marine Engineer and Naval Architect; Transactions of Institution of Naval Architects; Proceedings of Institute of Marine Engineers; Journal of American Society of Naval Engineers.

CHAPTER V

OCEAN ROUTES

Routing considerations, 58. Main ocean trunk line routes, 60. North Atlantic route, 60. Suez Canal route, 60. South African route, 61. South American route, 62. Caribbean routes, 63. North Pacific route, 63. Pacific coast-Australasian route, 64. Panama Canal route, 64. Triangular routes, 65. References, 67.

THE Oceans provide the great highways of international trade, which, from port entrance to port entrance, are free and open to all who observe the international rules of the road at sea. Although ocean traffic follows certain rather definite routes, no nation, and of course no company, can convert any route into an exclusive right of way, such as a railroad corporation possesses. A few short sections of some frequented routes of ocean traffic-the Panama, Suez, Corinth, and Kiel canals-are artificial, and subject to tolls, but their use is normally open to all upon equal terms. This simple but fundamental fact, that the sea is an open highway, causes ocean transportation to be governed by laws different from those controlling the railway service; and the main problems of transportation economics-competition, rates and fares, and government regulation—are radically affected by this difference between the railway and the ocean highway. The rapid growth of the regular steamship line service, which is more readily controlled by ocean conferences and agreements and more easily amenable to government regulation than the tramp service, i. e., the service rendered by independent, chartered vessels, has lessened the difference between ocean and rail. transportation somewhat, but has by no means placed them on a common footing.

ROUTING CONSIDERATIONS

The routes followed by ocean ships are determined mainly by the location and traffic importance of the areas between

which trade is being carried on, by the sphericity of the earth, by the size of the land masses lying between the trading areas, and by the location of fuel stations and the cost of coal or fuel oil. The routes followed by sailing vessels are determined also by the location and direction of ocean currents and prevailing winds. Among the minor causes influencing the routes of both steamers and sailing vessels may be mentioned the absence or prevalence in certain areas of the sea of floating ice, or of severe storms at different seasons of the year.

On account of the spherical shape of the earth, the shortest distance between any two places on the earth's surface is the arc of a great circle connecting the two points. This fact influences nearly all ocean routes, and particularly those across the north Atlantic and the north Pacific. For instance, Yokohama and San Francisco are in practically the same latitude-i. e., Yokohama lies directly west of San Francisco; but the short route between the two places, being the arc of a great circle, curves northward to the Aleutian Islands. It is only upon a globe that the relative length of ocean routes can be correctly shown, but the location of the principal ocean routes is indicated and their mileage lengths are stated on map No. 1 drawn on the Mercator projection.

The steamer can usually take the short route, but the sailing vessel must shape its course with reference to the currents and prevailing winds, although by so doing the distance may be greatly increased. In sailing from New York to Rio Janeiro, for example, a vessel will steer eastward with the winds and currents to the vicinity of the Azores, or nearly across the Atlantic, where, a longitude east of Cape St. Roque having been reached, the ship will turn toward the south, and, with the aid of the northeast trade winds north of the equator and of the southeast trades of southern latitude, will readily make the port of Rio Janeiro.

MAIN OCEAN TRUNK LINE ROUTES

Ocean routes are many in number and of different degrees of importance; there being, as in the case of railroads, trunk

lines and auxiliary routes, main lines and feeders. The following are the most important trunk line routes:

1. The ocean trunk line having the heaviest freight and passenger traffic is the one connecting the northeastern seaports of the United States with the entrance to the British Channel. Upon this north Atlantic trunk route more than one-sixth of the world's entire shipping is employed, it being the direct route between the principal commercial countries of the world. In order to conform as closely as possible to a great circle, this route skirts the coast of North America northward to the Banks of Newfoundland, and then curves across the Atlantic. The branch lines which unite in this north Atlantic trunk route reach American ports from Canada to the Caribbean, and European ports from the Baltic to the Mediterranean. Vessels plying between Europe and Gulf and West Indian ports take a course but slightly south of this route, and pass comparatively close to the coast of the United States. The route from Great Britain to the Panama Canal via New York is only 323 miles longer than the most direct course; and vessels plying between the West Indies or Central America and northern Europe frequently call at Hampton Roads to replenish their coal supplies.

2. The ocean trunk line ranking next to the one across the north Atlantic is the route from the eastern United States and western and southern Europe via the Mediterranean and the Suez Canal to India, the East Indies, China and Japan. Before the Suez Canal was opened in 1869, the ocean commerce of Europe and the United States with eastern countries was carried in sailing vessels around the Cape of Good Hope, and was small in comparison with the great volume of traffic now passing through the Suez Canal. As sailing vessels cannot navigate the Red Sea, only steamers use the Suez Canal route.

This ocean trunk line has an especially large number of branch lines or feeders both east and west of the canal. At Gibraltar the routes from the United States, Great Britain and western European countries join the main route for Suez;