Karl Wilhelm Scheele

1742-1786

Swedish Chemist and Druggist

Swedish-born chemist whose record as a discoverer of new elements, compounds, and chemical reactions has long remained unequaled.

Karl Wilhelm Scheele was born in Stralsund, Germany (formerly the capital of Swedish Pomerania.) Scheele's interest in chemistry began during his experience as an apprentice to an apothecary in the town of Goteborg. He had no formal education. His teacher, Swedish chemist Torbern Bergman (1735-1784), obtained a small pension for Scheele from the Stockholm Academy of Science, which the young apprentice in turn used to fund his chemical experiments. Scheele spent most of life in poverty, serving as an apprentice in Malmö and Stockholm before settling in as a pharmacist in the small town of Koping. He preferred remaining an apothecary to becoming a university professor.

His lack of career advancement, however, in no way parallels his scientific achievements. While in Koping, Scheele discovered more new substances than any scientist of his time, and perhaps ever since. In 1773 he proposed that air was composed of two gases, oxygen and nitrogen. Scheele prepared oxygen from various oxides but is rarely credited with the discovery. While his research anticipated English chemist Joseph Priestley's (1733-1804) discovery of oxygen, Scheele's only book Chemical Observations and Experiments on Air and Fire did not appear until 1777, after Priestley announced his results. There is little doubt, however, that he obtained the gas about 1772, two years before Priestley. Both Scheele and Priestly, however, failed to recognize the significance of their findings and today Antoine-Laurent Lavoisier (1743-1794) takes credit for the discovery.

Scheele published his first scientific paper in 1770, documenting his isolation of tartaric acid from cream of tartar. The free acid is widely used in carbonated drinks, effervescent tablets, and some gelatin products.

The young chemist discovered an extraordinary number of elements: chlorine, barium, molybdenum, tungsten, and manganese. He was the first to isolate chlorine and show that it could bleach cloth. Manufacturers in England and France put his research to commercial use.

While Scheele is credited with identifying chlorine and barium, he believed they were compounds, not elements. In the early 1800s, British chemist Sir Humphry Davy (1778-1829) correctly identified chlorine as an element.

In 1776 Scheele discovered uric acid while analyzing a kidney stone. In the last years of his life, he proved it was lactic acid that made milk sour. He was also the first to prepare the chemical compounds arsine and hydrogen sulfide. In 1783 he discovered the poisonous hydrocyanic acid, without realizing its toxic character.

Among his other discoveries were glycerine, copper arsenite (also referred to as the pigment Scheele's green), and the toxic gases hydrogen sulfide and hydrogen fluoride. Scheele also helped open doors to the modern world of photography by illustrating that sunlight removed salts from silver chloride, leaving only the metal behind.

Scheele died in 1786 at the age of 43. In 1931 the Collected Papers of Carl Wilhelm Scheele was published.

KELLI MILLER