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Jean Servais Stas

1911 Encyclopedia Britannica

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JEAN SERVAIS STAS (1813-1891), Belgian chemist, was born at Louvain on the 21st of August 1813. He studied for a medical career and took his doctor's degree, but soon turned to chemistry. In 1835 after much trouble he gained admission to J. B. A. Dumas's laboratory in Paris in order to continue a research on phloridzin which he had begun in an attic in his father's house, and he was associated with that chemist in several researches, including his redetermination of the atomic weight of carbon. In 1840 he left Paris on his appointment to the chair of chemistry at the Ecole Royale Militaire in Brussels. There he remained for more than a quarter of a century, but before he had served the thirty years necessary to secure a pension he was obliged to resign through a malady which affected his speech. He was then appointed to a post in connexion with the Mint, but gave it up in 1872, and spent the rest of his life in retirement in Brussels, where he died on the 13th of December 1891. Stas's name is best known for his determination of the atomic weights of a number of the more important elements. His work in this field was marked by extreme care, and he adopted the most minute precautions to avoid error, with such success that the greatest variation between his numerous by locusts, which the birds greedily devour. Another fact worthy of attention is that the y are often observed to affect trees or shrubs bearing rose-coloured ' flowers, as Nerium oleander and Robinia viscosa, among the blossoms of which they themselves may easily escape notice, for their plumage is rose-pink and black shot with blue.

individual determinations for each element was represented by from o

o05 to o

or. Though he started with a predilection in favour of Prout's hypothesis he was later led by the results he obtained and by his failure to find any evidence of dissociation in the elements to regard it as a pure illusion and to look upon the unity of matter as merely an attractive speculation unsupported by proof. Nevertheless, a few years before his death, a propos of the close approximation to integers presented by a number of the atomic weights of the elements when hydrogen is taken as unity, he remarked, "Il faut croire qu'il y a quelque chose la-dessous." In connexion with the poisoning of Count Hippolyte de Bocarme with nicotine in 1850 Stas worked out a method for the detection of the vegetable alkaloids, which, modified by Friedrich Julius Otto (1809-1870), professor of chemistry at Brunswick, has been widely used by' toxicologists as the Stas-Otto process.