Carl Wilhelm Scheele

In the 44 years of Carl Wilhelm Scheeles (pronounced Shay-ler) lifetime he helped to lay the foundation of inorganic chemistry, gas preparation, organic chemistry, photography and heat physics. Many of his discoveries proved later to be very important although Carl Wilhelm Scheele himself could not be aware of the way in which they were to develop. When he discovered that the purple end of the spectrum would blacken certain silver salts, he could not possible know that from this a photographic industry would arise. To him, his discoveries were just exciting and fascinating.

Carl Wilhelm Scheele was born in Sweden in 1742. He was a contemporary of Priestly and Cavendish. News of scientific experiments was freely circulated between theses three men and very often there is some doubt about which of the three was the real discovery of some fact. For example, in the Priestly Laboratory oxygen was being prepared and collected only a short time after it had been prepared by Carl Wilhelm Scheele.

Carl Wilhelm Scheele was the 7th child of a merchant. He had no formal scientific training and never sat a science examination in his life. This was probably  more of an advantage than a disadvantage, for scientific thinking at the time was bogged down by too many fake ideas. Theses did not bother Carl Wilhelm Scheele; he did not know half of them existed.

At the age of 15 he was apprenticed to an apothecary where he began studying on his own and experimenting in the shop. In the latter part of his life he kept his own apothecarys shop, rejecting offers of salaried posts which would have hampered him. He preferred to work on his own and not at the beck and call of someone else.

Carl Wilhelm Scheele was the first man to prepare the gases, oxygen and chlorine. Oxygen, he prepared by several different methods, starting from saltpetre, mercuric oxide, manganese dioxide and other substances. His chlorine was made by the action of hydrochloric acid on manganese dioxide. He collected his gases by squashing the air out of a pigs bladder and fixing it over the open end of a retort in which the gases were being made. The bladder swelled out as it filled with gas. Carl Wilhelm Scheele recognized that one gas he had prepared was the part of the air responsible for burning. Air was in fact a fifth oxygen, as Carl Wilhelm Scheele discovered when he burned some phosphorus to use up the oxygen in an air example.

The test now used in inorganic chemistry to discover the presence of a sulphate was yet another of Carl Wilhelm Scheeles discoveries. So was the preparation of tungstic acid. The tungsten metal now used for the filaments in electric light bulbs is extracted from its ore by converting the tungsten in the ore into tungstic acid.

Organic chemistry also interested him and many organic acids were the subjects of his study. Heat physics , too was his interest. Transfer of heat by convention and conduction was known at the time but Carl Wilhelm Scheele was the first man to observe heat transfer by radiation.

There are just a few of the many scientific discoveries made by him.

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