2 



L. F. Nilson, 



acid. Thus Wohler 1 ), a couple of years before Muspratt published his 

 paper, obtained a tetraselenite of zinc, of which the latter seems to be 

 ignorant; in 1853 Kohler 2 ) gave some information of the selenites of mer- 

 cury, and Kuhlmann 3 ) described in 1864 some of the selenites of thallium. 

 Finally, in the latest time, Atterberg 4 ), in a treatise on glucinum-salts, 

 made mention of three basic salts of this metal; Cleve 5 ), in the course of 

 his researches on the earth-metals, has also examined salts of selenious 

 acid with yttrium, lanthanum, didymium and thorium; Hoglund 6 ) has contri- 

 buted to the knowledge of erbium in this respect, and Jolin 7 ) to the 

 knowledge of the selenites of cerium. 



As the statements of these authors will be more particularly spoken 

 of in the following pages, it may be superfluous to give here a more de- 

 tailed account of them. 



As Muspratt's treatise, as already mentioned, cannot pretend to 

 supply the rather scanty knowledge of the salts of selenious acid which 

 we owe to Berzelius, and as the other authors here mentioned have only 

 treated of particular salts, I undertook the investigation of the compounds 

 of this acid, of which, accordingly, an account will now be given. 



My original intention was indeed to apply myself to the study of its 

 double salts, supposing that these ought to afford as interesting a matter 

 for an examination, as the known double salts of sulphurous acid, already 

 treated of by several authors. But even a superficial review of the litera- 

 ture on this subject suggesting that there is but little known about the 

 selenites in general, I thought it useful to give some previous attention to 

 the simple salts of the acid. The results of my investigations are stated 

 below in more than one hundred, analytically determined compounds, whereas 

 the double salts will be treated of in another paper, which I hope soon be 

 able to publish. Before I enter upon the peculiar subject of my treatise, 

 it will be convenient previously to give an account of the manner in which 

 pure selenious acid has been obtained. 



') Ann. d. Chemie u. Pharm. LXIII S. 279. (1847). 



2 ) Ann. d. Ph. u. Ch. LXXXIX S. 146. 



3 ) Bull, de la Soc. chim. de Paris [2] II p. 330. 



4 ) K. Sv. Vet. Akad:s handl. 1873 N:o 5. 



5 ) Bih. t. Sv. Vet. Akad ; s handl. I N:o 8, II N:o 6, 7. 8. 

 °) Bih. t. Sv. Vet. Akad:s handl. I N:o 8. 



7 ) Bull, de la Soc. chim. [2] XXI p. 533. 



