Berzelius, Selenium and Silicon

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Jons Jakob Berzelius was probably the best experimental chemists of his generation and, given the crudeness of the laboratory equipment, maybe the best of all time. Unlike Lavoisier, who could afford to by the best laboratory equipment available, Berzelius worked with minimal equipment in very plain surrounings. One of Berzelius's students described the Swedish chemists's workplace: "The laboratory consisted of two ordinary rooms with the very simplest arrangements: there were neither furnaces nor hoods, neither water system not gas. Against the walls stood some closets with the chemicals, in the middle the mercury trough and the blast lamp table. Against the walls stood some closets with the chemicals, in the middle  the mercury trough and the blast lamp table. Beside this was the sink consisting of a stone water holder with a stopcock and a pot standing under it. Next door in the kitchen stood a small heating furnace".

In these simple facilities Berzelius performed more than 2000 experiments over a 10-year period to determine accurate atomic masses for the 50 elements then known. Berzelius made many contributions to chemisty. He also discovered the elements cerium, thorium, selenium and silicon are particularly important in today's world. Berzelius discovered selenium in 1817 in connection with his studies of sulfuric acid. In these simple facilities Berzelius performed more than 2000 experiments over a 10-year period to determine accurate atomic masses for the 50 elements then known. Berzelius made many  ontributions to chemisty. He also discovered the elements cerium, thorium, selenium and silicon аre particularly important in today's world. Berzelius discovered selenium in 1817 in connection with his studies of sulfuric acid.

For years selenium's toxicity has been known, but only recently have we become aware that it may have a positive effect on human health. Studies have shown that trace amounts of seleniumin the diet may protect people from heart disease and cancer. One study based on data from 27 countries showed an inverse relationship between the cancer death rate and the selenium content of soil in a particualr region (low cancer death rate in areas with high selenium content). Another research paper reported an inverse relationship between the selenium content of the blood and the incidence of breast canser in women. Selemium is also found in the heart muscle and may play an important role in proper heart function. Silicon is the secon most abundant element in the eath's crust, exceeded only by oxygen. Berzelius prepared silicon in its pure form in 1824 by heating silicon tetrafluoride (SiF4) with potassim metal. Today, silicon forms the basis for the modern microelectronics industry centered near San Francisco in a place that has come to be known as "Silicon Valley". 

The technology of the silicon chip with its printed circuits has transformed computer from room-size monsters with thousand of unreliable vacuum tubes to desktop and notebook-size units with troube-free "solid-state" circuitry.