successful "orthopters" had already been transporting people by air
knowledgeable men believed successful flights would be achieved one day
It is clear from the passage that Leonardo da Vinci had considered the possibility of air travel in some depth
concentrated more on science than on art
had ignored the existence of air pressure
had made detailed studies of how a boomerang returns to its thrower
managed to build the first helicopter but it did not fly
We learn from the passage that J. Etienne and Joseph M. Montgolfier ignored the presence of atmospheric pressure
succeeded in a type of flight conceived several centuries earlier
made many drawings, but never built a successful machine
were the first men to imagine air balloons which could rise in the sky
did not think helicopters could ever be successful
120 TOURISM Tourism is travelling for recreation. Tourists originated when large numbers of middle class people began to join the more wealthy aristocratic travellers. As societies became wealthier, and people lived longer, it became more and more likely that lower-middle class and middle class people steadily employed would retire in good health and with significant savings.
A tourist can usually be seen as clearly "out of place" in his current surroundings, so he is not confused with other travellers. The term "tourist" is tied to the activity of taking a tour or sightseeing. It is not limited to travelling, but used as a description of a person who enters a situation or culture, for a brief time, requiring knowledge that he does not have.
The tourist can be interested - among other things - in the new place's culture or its nature. Wealthy people have always travelled to distant parts of the world, not, for any special purpose, but simply for travelling as an end in itself: to see great buildings or other works of art; to learn new languages; and to taste new cuisines.
Organized tourism is now a major industry around the world and many national economies are now heavily reliant on tourism.
The term tourism is sometimes used in an uncomplimentary manner, implying a shallow interest by tourists in general in the societies and natural wonders they visit.