Аж үйлдвэржилтийн хувьсгал. Аж үйлдвэрийн 1р хувьсгал …
1846 — The sewing machine is invented by Elias Howe. 1853 — Elisha Otis invents a safety break for elevators making them practical and safe for the first time. This allows for tall buildings and skyscrapers to be built. 1856 — The Bessemer Process for making steel is invented by Henry Bessemer.