362 Introduction to the Study of Science 



pounds, can it be made to support a weight of 100 pounds if it is hung 

 very slack between two posts ? If stretched taut before the weight is 

 attached? 



SUGGESTIVE QUESTIONS 



1. A writer in the first century of the Christian era mentions a 

 delay of several days in which a ship waited for a fair wind, that is, 

 one in the direction he wished to go. Would a modern sailing vessel 

 have waited? Explain. 2. Can a sailing vessel go directly into the 

 wind? Why? 3. A big bellows was fastened to the deck of a ship 

 and made to blow on the sails in a calm. The ship moved slowly 

 backward. Explain. 4. If a windmill were placed on a boat and 

 geared to a screw propeller, would it make the boat go? Would it 

 force it directly into the wind? (The answer to the latter question 

 depends upon the slant of the windmill blades on the wind, and the 

 pitch of the propeller blades.) 



V. THE STEAMSHIP 



169. The modern ocean liner. Within the past hundred 

 years the sailing ship has been rapidly replaced by the steam 

 vessel both for passenger and for freight traffic. The demand 

 for speed, safety, or seaworthiness, and comfort in travel has 

 affected water transportation as well as that on land. The 

 study of the behavior of water and winds, the invention of 

 means to overcome their adverse influence, and to reduce to a 

 minimum friction and waste, have brought about the building 

 of ships which are marvels of grace, utility, and speed. Com- 

 pare the Clermont of Robert Fulton with a modern Atlantic 

 liner and with a destroyer or torpedo boat. In speed, in safety, 

 in size and economy of operation and maintenance, the differ- 

 ences are most pronounced. A transatlantic liner to-day (Fig. 

 128) makes twenty-five or more knots, and a destroyer does its 

 forty knots, equivalent to forty-five or more land miles per hour. 

 A modern liner carries a crew of more than 1000, and a passen- 

 ger list of from 3000 to 4000, besides thousands of tons of 

 freight in its holds. Equipped with all possible conveniences 

 and the luxuries of the best hotels, the modern liner is a veritable 



