보이지 않았던 별

과학동아 1990년 09호

the 1960s in connection with Stonehenge, the impressive circles of giant stones(some of them fallen) in southwestern England. Reconstructions of what it must have looked like when all the stones were in place have led some people to believe that sighting along certain stones located the rising sun on the day of summer solstice. The rock arrangements may have served as a Stone Age observatory ...

박테리아 광부들

과학동아 1990년 08호

traveled vout into the Atlantic Ocean and discovered tin ore in the 'Tin Isles,' which may have been Cornwall in England, and grew rich by monopolizing this valuable material until iron made it comparatively obsolete.Since then, human beings have searched the world over for natural concentrations of ores containing desirable metals. It was not only a matter of gold, silver, copper and iron, ...