Other viruses that can cause colds include coronavirus, respiratory syncytial virus, influenza and parainfluenza. Colds cause a lot of people to stay home. The CDC says 22 million school days are lost each year in the U.S. because of them. Some estimates say that Americans have 1 billion colds a year. For more detail, see Common Cold Causes. How a Common Cold Starts. You can catch it from another person who is infected with the virus. This can happen by direct physical contact with someone who has a cold, or by touching a surface contaminated with their germs -- like a computer keyboard, doorknob or spoon --- and then touching your nose or mouth.
The hypocaust system. The hypocaust system (hypocaustum in Latin) was a heating system used in (wealthy) Roman homes and Roman baths, and the closest thing to central heating today. The hypocaust was a system that circulated hot air under the floor and surrounding walls. Hypocaust construction
Roman houses were so well built, if you were rich, that many examples of Roman houses exist throughout the Roman Empire.If you were poor in Rome, you lived in simple flats or apartments â the inside of these places was symbolic of your lack of wealth.ouses were also centrally heated by what was known as a hypocaust. This was under-floor heating. Slaves were charged with keeping the hypocaust both clean and alight during the day. This system of heating was also used to keep some Roman baths hot if they had no access to naturally heated water.