Sarah Mather
Sarah Mather (1796, in Brooklyn – June 21, 1868) was an American inventor, best remembered for patenting the first underwater telescope, a predecessor of the periscope in 1845. Background. Sarah Porter Stiman was born in New York in 1796. In 1819, when she was 23 years old, Stiman married Harlow Mather and had at least one daughter. They lived in Brooklyn, New York. Submarine telescope and lamp. On April 16, 1845, Sarah Mather was granted US Patent No. 3995 for an invention she called a “submarine telescope,” which was the very first telescope that could be used underwater. The  invention consisted of a tube that was formed by several joints screwing together which can be extended to any desired length and a glass globe that served as a telescope. In addition to the tube of the telescope itself, there was a lamp attached to one end which allowed the user to make examinations underwater with illumination. Mather’s original intention in creating the apparatus was for examining the sunken ship’s hull without having to remove it from the water. Later, her invention was applied to various areas, such as discovering objects underwater, fishing, and examining any underwater activity . On July 5, 1864, Mather was granted another patent (US Patent No. 43465) for an “improvement in Submarine Telescopes” which has improved the performance of the reflector and the lamp under great water pressure. Legacy. The “submarine telescope” devised by Sarah Mather made it possible for marine navigation ships to inspect the depths of the ocean and to know the distance and position of particular objects underwater. At the time Mather came up with the invention of an underwater telescope, submarine warfare during the Civil War began. Her invention was very important to the North in detecting the underwater activity  of the enemy forces. Beyond its military use, Mather’s invention of the underwater telescope serves as the predecessor of the periscope that was later invented in 1845, which is still in use today for marine navigation, and in the naval industry.