Since Roman times, Bath’s hot mineral springs have pumped a quarter of a million gallons of spring water a day at a steady 49°c. The original Pump Room was erected in 1706. In 1708, Thomas Harrison built the Bath Assembly House, for which the public paid fees to dance and gamble. Visitors promenaded up and down the Pump Room, drinking the waters from 8am to 3pm, catching up on gossip, seeing and being seen, while an orchestra played in a semi-circular gallery above their heads.
During the mid-18th to early 19thcentury, Bath’s population exploded from 2,000 to 38,000, becoming the eighth largest city in England by 1801. The Pump Room was enlarged in 1751, a new portico added in 1786, and a new frontage constructed in 1791. The number of visitors continued to swell, however, and in 1796 an entirely new room was built, 85 feet long, 46 feet wide, and 34 feet high.