In the year 1817 Berzelius ') published his discovery of selenium. In 

 discussing its chemical properties, he also gave a report of the only com- 

 pound of oxygen obtained by him of the new element, viz. selenious acid 

 (or, as he then called it, selenic acid) and of its salts with most bases then 

 known. In doing so he, for the most part, does not go beyond experiments 

 of reaction, only rarely stating the quantitative composition of a very few 

 salts, with the view of ascertaining the basicity of the new acid. For this 

 purpose he makes use of the selenites and diselenites of sodium and barium 

 and the selenites of lead and silver. He also proved the existence of tetra- 

 selenites of tiie alkaline metals and diselenites of a good deal of other 

 ones; in a word, he set forth the general characteristic of the basicity of 

 selenious acid, for which chemistry is still at the present time indebted 

 almost to him alone. I think we may make this assertion, without fear of 

 mistake, though Muspkatt 2 ), many years later, has made the salts of sele- 

 nious acid the object of his researches. For as far as his statements are 

 not a mere repetition of what Berzelius had published thirty years before 

 — and this is often the case — the results of his work, owing to deficient 

 and erroneous methods, appear little calcutated to inspire confidence, and 

 it will be evident from the following pages, that most of the formulae he 

 furnishes and thinks himself authorized to assume for a considerable num- 

 ber of salts, are erroneous. 



No author, as far as I am aware, except the two above mentio- 

 ned, has made the matter in question the exclusive object of any research. 

 There occur, however, some scattered reports on a few salts of selenious 



') Afhandlingar i Fys., Kemi och Miner. VI. s. 42 — 144. 

 2 ; The Quart. Journ. of the Chem. Soc. of London 1849 p. 52. 

 Nova Acta Reg. Soc. Sc. Ups. Ser. III. 



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