And a kittenâs teeth first come in between two to four weeks; their more permanent set appears at around four months of age. So if you open a catâs mouth and find permanent, white teeth, the feline is likely to be around a year old. popular misconception is that cats age seven years (in human years) for each calendar year. In fact, feline aging is much more rapid during the first two years of life.
Sarah Boone (1832-1904) was an African American inventor who on April 26, 1892, obtained United States patent rights for her improvements to the ironing board.
Iron and steel smelting. Iron and steel smelting skills are invented in antient China. [nipic.com] It has been confirmed by archaeological evidence that iron, made from melting pig-iron, was developed in ancient China in the early 5th century BC during the Zhou Dynasty (1050 BCï¼256 BC). During the Shang Dynasty (1600 BCï¼1046 BC) to the Eastern Zhou Dynasty (1050 BCï¼256 BC), China went into a flourishing period for steel smelting.