In the nineteenth century, oceanography benefited from the new desire to study phenomena on a global scale. Many scientists collected information on the chemical composition, temperature, and pressure of the ocean at various depths and in different Line regions. The difficulty of gathering information about the ocean depths was immense. 

     At first ii was believed that the temperatures in the depths never fell below 4 degrees Celsius, until it was shown that the figures were distorted by the effect of pressures on the thermometers. There was intensive study of tides and ocean currents; and a number of physicists examined the forces responsible for the movements of the water. For example, James Reonell provided the first accurate map of the currents in the Atlantic. 

     Ocean, and the United Slates Coast Survey made extensive studies of the Gulf Stream. The zoologist Edward Forbes argued that no lire existed below a depth of 300 fathoms (about 600 meters) a view widely accepted until disproved by the voyage of the British research vessel HMS Challenger(1872-1876)The HMS Challenger expedition provided valuable information about the seabed, including the discovery of manganese nodules IS that are now being seen as a potentially valuable source of minerals. 

     The first detailed map of the seabed was provided for the Atlantic by the American geographer Matthew F. Maury- He devised new techniques for measuring ocean depths, and his work proved of great value in laying the first transatlantic telegraph cables. He also studied global wind patterns and was able to provide sailors with guides that 20 significantly reduced die time taken on many routes. Some oceanographers believed that the winds were responsible for producing ocean currents such as the Gulf Stream, but Maury disagreed. He argued that they were produced by changes in the density of seawater due to temperature, which Bet up systems of movement between warm and cool regions of the world. Maury believed that the circulation of a warm current would 25 produce ice-free sea around the North Pole, a claim not disproved until Fridtjof Nansen allowed his vessel The Pram to be carded to within a few degrees of the pole in the years 1893-1896.

 "Look, it's Baldy!" A boy shouted in my direction across the playground. Even though I was used to regular insults(侮辱) because of the   11   on my hed, it was   12   horrible to hear. I sighed as I headed back to the class.

　　When I was just 20 months old, I suffered serious   13   after a bowl full of hot oil fell on my head. I was   14   to hospital and had to say there for weeks while the doctors   15   to save my life. "Holly's very   16   to be alive," they told Mum and Dad. "But she'll be   17   with scars on her head, and of course her hair won't grow there."

　　As a child, I cared much about my scars, so I   18   wore a scarf to cover them up when I left home.   19   I didn't, people would call me horrible names like Baldy. Although my friends were always comforting me ,they never   20   understood how it felt.

　　Then through the hospital I was   21   to a children's burns camp, where children like me can get any help. There, I   22   14-year-old Stephanie, whose burns are a lot more serious than mine. But she is so   23   that she never lets anyone put her down. "You shouldn't   24   what people say about what you look like because we're not different from anyone else, Holly," she   25   me. "And you don't need to wear a scarf because y0ou look great   26   it!" For the first time in my life I could speak to someone who'd been through something   27  . So weeks later, at my 13th birthday party,   28   by her bravery, I gave up my scarf and showed off my scars. It felt amazing not having to   29   away behind my scarf.

　　Now, I am   30   of what I look like and much happier, because I have realized it is your personality（个性）that decides who you truly are.