304 



TRANSPORTATION 



FIG. 506 



The steam engine 

 was first applied to 

 water transportation in 

 1803 when Robert 

 Fulton, an American 

 inventor working in 

 Paris, launched a boat 

 driven by steam on the 

 Seine River. In 1807 he 

 built and launched the 

 Clcnnont (Fig. 507) on 

 the Hudson River and 

 was soon able to open 

 a packet line between 

 New York and Albany. 



The Atlantic Ocean was first crossed by a steam 

 propelled ship, the Savannah, in 1819. Regular pas- 

 senger service was established between England and 

 America in 1838 when the liner Great Western was 

 put into service. The journey required fifteen or six- 

 teen days. Comparison of this time with that of five or 

 six days required by the modern liner tells the story 

 of progress of the past century in ocean travel. Figure 

 508 shows one of the most modern of ocean liners, the 

 Queen Mary. 



The two largest ships afloat are the Normandie, 

 owned by the French Line, and the Queen Mary, owned 

 by the Cunard-White Star Line. The Normandie is 

 1,029 feet in length and has a displacement of 79,000 



gross tons. The Queen Mary is 1,018 feet long and has 

 a displacement of 83,000 gross tons. 



Why do some substances float and others sink? 

 Objects appear to be lighter when they are sub- 

 merged in water than they are in air. Have you ever 



Paul's Photos 



FIG. 508. THE Queen Mary 



FIG. 507. THE Clermont 



observed how much easier it is to lift a heavy stone 

 under water than it is to lift the same stone out of 

 water. 



The principle of buoyancy was first studied and ex- 

 plained by Archimedes, a Greek mathematician and 

 scientist who lived from 287 to 212 B.C. in the city of 

 Syracuse on the island of Sicily. 



The story is told that King Heiron of Syracuse em- 

 ployed a goldsmith to make a crown of pure gold. 

 When the crown was delivered the king had reasons 

 to believe that the goldsmith had not made the crown 

 of pure gold but had used part silver, keeping the re- 

 maining gold. The king had become a close friend of 

 Archimedes and so asked him if there was some way 

 in which he could tell whether the crown was pure 

 gold without cutting into it. Archimedes spent some 

 time working on this problem and one day while tak- 

 ing a bath in the public baths he observed that his 

 body displaced water. He at once applied this knowl- 

 edge to the solution of the problem of the crown and 

 found that the goldsmith had defrauded the king. 

 Archimedes was also the discoverer of the principle 

 of the lever. See page 158. 



The experiment at the beginning of this topic has 



