Geothermal heating a total capacity of 15 GW extracted 88 PJ of heat energy for space heating. Global ground-source heat pump capacity is growing by 10% annually. Hot springs have been used for bathing at least since Paleolithic times. The oldest known spa is a stone pool on China's Mount Li built in the Qin dynasty in the 3rd century BC, at the same site where the Huaqing Chi palace was later built. Geothermal energy supplied channeled district heating for baths and houses in Pompeii around 0 AD. In the first century AD, Romans conquered Aquae Sulis in England and used the
Escadrille SPA.31 use of a Roman archer as the "escadrille" insignia. In October, "Escadrille N 31" shifted to support "II Armee". The following month, the unit was incorporated into "Groupe de Combat II". "Escadrille 31" began receiving SPADs on 7 January 1917. However, it would not totally rearm with SPADs until 17 September, when it was renamed "Escadrille SPA 31". The "escadrille" would serve as part of "GC II" through the remainder of the war. When the armistice came, it had been credited with 42 aircraft and four observation balloons destroyed, and have earned two citations from Army Corps. Escadrille SPA.31 Escadrille