But science not only provides knowledge about nature: it also provides a means for controlling nature. So besides general ideas, science also affects practical affairs and everyday life. Perhaps the most obvious example concerns transport. Up to the end of the eighteenth century, transport on land differed very little from what it had been in Roman times. A Roman officer in second-century, Britain could get from London to York just about as quickly and comfortably as an eighteenth-century gentleman. Owing to the compass and to improved design of ships, sea transport had improved a little, but not much. Then came the invention of the steam-engine, and its improvement, which was dependent on the general scientific knowledge of the time. Steamships, and railways with steam engines, completely changed the business of travel and of the transport of goods. The internal combustion engine, again based on the scientific study of heat and how it is generated by gas explosions, made possible first the motor-car and the diesel engine and then the aeroplane. Now people are talking of the possibility of flying at five hundred miles on hour or more by means of rocket propulsion in the thin higher layers of the atmosphere. It is interesting to note down the highest speeds possible for land, sea and air travel every ten years from 1820 to the present day.Similarly with communication. Not only did the steam engine, and then the aeroplane, speed up the sending of letters and newspapers, but the discoveries about electricity made possible first the telegraph, then the telephone, then wireless, and today television is just about to become practical. As a result of science, the possibilities of tying the world together by quick transmission of facts and ideas have completely changed in less than a century.1. Which two powers does science equip us with?2. Which two areas of knowledge are talked about here?3. Which inventions have led to the improvement in transportation?4. Which inventions have led to the improvement in communication?5. How could motor car, diesel engine and aeroplane be possible?6. What have the discoveries about electricity made possible?7. From when to when have the speeds changes taken place?8. Locate from the passage the antonyms of the following words :(i) theoretical(ii) slowly(iii) external(iv) lower