Air conditioning
Modern air conditioning emerged from advances in chemistry during the 19th century, and the first large-scale electrical air conditioning was invented and used in 1902 by US inventor Willis Carrier. The introduction of residential air conditioning in the 1920s helped enable the great migration to the Sun Belt in the United States.
Alexander Cumming
Alexhander Cumming (sometimes referred to as Alexander Cummings) FRSE (1733 –8 March 1814) was a Scottish watchmaker and instrument inventor, who was the first to patent a design of the flush toilet, which had been pioneered by Sir John Harrington, but without solving the problem of foul smells. The S-trap (or bend) was invented by Cumming in 1775 to retain water permanently within the bowl, thus preventing sewer gases from entering buildings. It survives in today's plumbing modified as a U- or J-shaped pipe trap located below or within a plumbing fixture.