Part 5 (1/2)
What has been the effect of cheap steel on ocean navigation?
Discuss the difference between a screw-steams.h.i.+p and a side-wheeler; a s.h.i.+p and a schooner. How are vessels steered?
How does a triple-expansion engine differ from an ordinary steam-engine?
Cargoes are carried by water across Europe from Havre to Ma.r.s.eilles, and from The Hague to the mouth of the Danube; ill.u.s.trate the route on a map of Europe.
The following instruction occasionally is found in the pilothouse of a vessel--what is its meaning?
”Green to green and red to red-- Perfect safety; go ahead.”
From the chart on p. 49 show how a pilot uses the range lights in entering New York Harbor.
The new freighter Minnesota is designed to carry a load of 30,000 tons; how many trains of fifty cars, each car holding 30,000 pounds, are required to furnish her cargo?
From the map on pp. x-xi describe the new ocean routes that will be created by an interoceanic ca.n.a.l across the American continent.
FOR COLLATERAL REFERENCE
Photographs or ill.u.s.trations of various steam and sailing craft.
An Atlantic Coast Pilot Chart--any month.
A map showing the ca.n.a.ls of the United States.
A map showing the ca.n.a.ls of Europe.
[Ill.u.s.tration: A MODERN LOCOMOTIVE--THE TWENTIETH CENTURY LIMITED AT A SPEED EXCEEDING NINETY MILES AN HOUR]
CHAPTER VI
TRANSPORTATION--RAILWAYS AND RAILWAY ORGANIZATION; PUBLIC HIGHWAYS
In the United States and western Europe, in spite of the low cost of water transportation, the railways have almost wholly monopolized the transportation of commodities. This is due in part to the saving of time in transit--for under the demands of modern business, the only economy is economy of time--and in part to prompt delivery at the specified time.
Into a large centre of population like New York, London, or Berlin, many millions of pounds of perishable food-stuffs must be brought daily for consumption. Now these food-stuffs must be delivered with promptness, and no delay can be tolerated. A s.h.i.+pper having half a million pounds of meat or a hundred thousand pounds of flour or a car-load of fruit to deliver can take no risks; he sends it by rail, not only because it is the quickest way, but because experience has shown it to be the most prompt way; as a rule, it is delivered on the exact minute of schedule time.
Cargoes of silks and teas from China and j.a.pan might be sent all the way to London by water, but experience has shown a more profitable way. The consignments are sent by swift steams.h.i.+ps to Seattle; thence by fast express trains to New York; there they are transferred to swift liners that take them across the Atlantic to European ports. And although this method of s.h.i.+pment is enormously expensive as compared with the all-water route, the saving of time and certainty of prompt delivery more than offset the extra cost of delivery.
In the last half of the nineteenth century the cost of haulage in the United States by rail decreased so materially that in a few instances only--notably the Great Lakes and the Hudson River--do inland waters compete with the railways.[12] This is due in part to better organization of the railways, but mainly to the subst.i.tution of Bessemer steel for iron rails and the great improvements in locomotives and rolling stock.
The use of a steam-driven locomotive became possible for the first time when Stephenson used the tubular boiler and the forced draught,[13]
thereby making steam rapidly enough for a short, quick stroke. In 1865 a good freight locomotive weighing thirty tons could haul about forty box-cars, each loaded with ten tons. This was the maximum load for a level track; the average load for a single locomotive was about twenty-five or thirty cars. Heavier locomotives could not well be used because the iron rails went to pieces under them.
The invention of Bessemer steel produced a rail that was safe under the pounding of a locomotive three or four times as heavy as those formerly employed; it produced boilers that would carry steam at 250 instead of 60 pounds pressure per square inch. As a result, with only a moderate increase in the fuel burned, a single locomotive on a level track will haul eighty or ninety box-cars, each carrying nearly seventy thousand pounds.[14]
The application of the double and the triple expansion principle has been quite as successful with locomotive as with marine engines in saving fuel and gaining power--that is, it has decreased the cost per ton-mile of hauling freight and likewise the cost of transporting pa.s.sengers. Enlarged ”fire-boxes,” or furnaces,[15] enable steam to be made more rapidly and to give higher speed.[16] Only a few years ago forty-eight hours was the scheduled time between New York and Chicago; now there are about forty trains a day between these two cities, several of which make the trip in twenty-four hours or less.