George Jennings established a business manufacturing water closets, salt-glaze drainage, sanitary pipes and sanitaryware at Parkstone Pottery in the 1840s, where he popularized the flush toilet to the middle class. At The Great Exhibition at Hyde Park held from 1 May to 15 October 1851, George Jennings installed his Monkey Closets in the Retiring Rooms of The Crystal Palace. These were the first public pay toilets (free ones did not appear until later), and they caused great excitement. During the exhibition, 827,280 visitors paid one penny to use them; for the penny they got a clean seat, a towel, a comb, and a shoe shine. "To spend a penny" became a euphemism, for going to the toilet.