The first half of the nineteenth century witnessed a steady improvement in stove design. Cast iron stoves replaced those made of masonry and their size shrank to allow them to be incorporated into the domestic kitchen. By the 1850s, the modern kitchen, equipped with a cooking range, was a fixture of middle-class homes. In 1850 Mary Evard invented the Reliance Cook Stove, which was divided in two with one half for dry baking and the other half for moist. Patents issued to Mary Evard are US76315 and US76314 on April 7, 1868. She demonstrated this stove with her husband at the St. Louis World's Fair.