Wireless Intraoral Camera with samll screen

The oldest sample of mercury dates to about the fifteenth or China dental chair supplier. It was found in an Egyptian tomb at Kurna, stored in a small glass container. Mercury and cinnabar are both mentioned in ancient manuscripts. The Chinese, Hindus, Egyptians, Greeks, and Romans all recorded information about the element and its ore. Greek philosopher Theophrastus (372-287 B.C.), for example, described a method for preparing mercury. Cinnabar was rubbed together with vinegar in a clay dish. Theophrastus wrote that the cinnabar had been found in silver mines. When the metal was first made, he said, people thought it might contain gold. They were misled by the metal's shiny appearance. They soon realized, however, that it was quite different from gold.Some mercury compounds are known to be poisonous. For example, mercuric chloride (corrosive sublimate) was often used to kill pests and, sometimes, people. On the other hand, some mercury compounds have been used as medicines. For instance, mercurous chloride (calomel) was long used as a cure for skin rashes. In the recent past the dangers of mercury have become better known. As a result, use of mercury and its compounds is now being either phased out or made cautiously.

Many reports on mercury told of Dental Low Speed Handpiece. Slaves who worked in Roman mercury mines, for example, often died of exposure to mercury. Strangely enough, trees and plants around these mines were not affected. Mercury was sometimes very dangerous and sometimes quite safe. People even drank from streams that ran through mercury mines. Scientists now know that mercury's effects depend on the form in which it occurs.Mercury amalgams have also been around for a long time. An amalgam is a combination of mercury with at least one other metal. Amalgams are formed when a metal, such as silver, dissolves in mercury. The process is similar to dissolving salt in water. Amalgamation is used in mining to remove silver from ore. The silver dissolves in the mercury and a silver amalgam is formed. Heating the amalgam releases the silver. This method was used by miners as early as the sixteenth century.

Mercury is the only liquid metal. Wireless Intraoral Camera with samll screen , there is only one other liquid element, bromine that is a non-metal. Mercury can be frozen at a temperature of –38.85°C (–37.93°F) and boiled at 365.6°C (690.1°F). Its density is 13.59 grams per cubic centimeter. Mercury has two physical properties of special interest. First, it has very high surface tension, a property of liquids that make them act as if they are covered with a skin. For example, some water bugs are able to walk on the surface of water. With care, one can float a needle on the surface of water. These incidents are possible because of water's surface tension.Mercury is also a very good conductor of electricity. This property is used in a number of practical devices. One such device is a mercury switch, such as the kind that turns lights on and off. A small amount of mercury can be placed into a tiny glass capsule. The capsule can be made to tip back and forth. As it tips, the mercury flows from one end to the other. At one end of the capsule, the mercury may allow an electric current to flow through a circuit. At the other end, no mercury is present, so no current can flow. Mercury switches are easy to make and very efficient. Mercury is moderately active. It does not react with oxygen in the air very readily. It reacts with some acids when they are hot, but not with most cold acids.