The force of attraction increases as an electron and a proton approach each other. And it varies inversely as the square of the distance between the particles. The electron and the proton have a negative electrostatic charge and a positive electrostatic charge respectively. Each charge-and the force associated with that unit of charge-is constant-and equal.
There are pools/baths dating as far back as the Ancient Greeks and Ancient Egypt however I believe there would have been something far more prehistoric than this (albeit far less advanced). The first heated swimming pool was built by Gaius Maecenas of Rome in the first century BC. Gaius Maecenas was a rich Roman lord. The great bath at the site of Mohenjo-Daro was most likely dug during the 3rd millennium BC. This pool is 12 by 7 meters, is lined with bricks and was covered with a tar-based sealant.
Baltimore: A City of Firsts. 1743 - First professional sports organization in the United States-Maryland Jockey Club. 1773 - First US stage coach route-Baltimore to Philadelphia. 1774 - First Post Office System in the United States. 1778 - First independent corps in the Revolutionary War Army-organized by Count Casimir Pulaski. 1783 - First dredger in the world-the Baltimore Mud Machine, was invented by Andrew and John Ellicot.