Devices sold as siphons often come with a "siphon pump" to start the siphon process. They re-examined the theories of the siphon and ran experiments on siphons in air pressure. The aqueducts were well engineered and included several siphons. Bivalves with long siphons may also have siphonal ganglia to control them. Axon siphons most of Lyra's bioelectric energy, absorbing her powers. During further larval stages they develop siphons and gills. The pool was filled with water using siphons and pumps. In those bivalves which have siphons, the siphons are paired. Those bivalves that have siphons, have two of them. Egyptian reliefs from 1500 BC depict siphons used to extract liquids from large storage jars. Such self-priming siphons are useful in some rain gauges and dams. Soda makers may reach a higher level of carbonation than home soda siphons. Large siphons may be used in municipal waterworks and industry. He also said that a suction pump was used in siphons to discharge Greek fire. He sent Harvey siphons from the mollusc preserved in sugar.