Unfortunately, for history’s sake, little is known about inventor Sarah Mather. One source believes her to have been married with at least one daughter. There don’t appear to be any records of other inventions by Sarah Mather except an improvement on the first, her submarine telescope, which was an important naval innovation. On April 16, 1845, Brooklynite Sarah Mather was granted a patent (US Patent No. 3995) for an invention she called a “submarine telescope” – an “Apparatus for Examining Objects Under the Surface of the Water”. She explained, “The nature of my invention consists in constructing a tube with a lamp attached to one end thereof so to be sunk in the water to illuminate objects therein, and a telescope to view said objects and make examinations underwater. . . . It will at once be obvious that the above-named lamp and telescope can be used for various purposes, such as the examination of the hulls of vessels, to examine or discover objects underwater, for fishing, blasting rocks to clear channels, for laying foundations or geological formations, the lamp is used for lighting the objects while inspected by the telescope.” Primarily, her invention was used to examine a ship’s hull without having to remove it from the water. On July 5, 1864, she was awarded US Patent No. 43465 for an “Improvement in Submarine Telescopes”. With the beginnings of submarine warfare during the Civil War, her invention was also useful in detecting Confederate underwater activity. SOURCE : http://historydepot.files.wordpress.com/2014/06/marthacostonpic.jpg