Biography of Berzelius. 5 



and was thus able to furnish even those mineralogists who 

 but unwillingly admitted the influence of chemistry upon 

 mineralogy, with an extremely welcome gift, since, by simple 

 blow-pipe experiments, it was possible to distinguish minerals 

 with ease and certainty, especially among siliceous com- 

 pounds, which were with difficulty, or only ambiguously, 

 recognisable by means of their external characters. 



This work bore so manifestly the stamp of perfection, even 

 on its first appearance, that, with the exception of Plattner, 

 in Freiberg, no one has contributed any essential additions 

 or improvements to blow-pipe investigations ; and it is quite 

 as indispensable to the chemist and mineralogist at the pre- 

 sent day as it was thirty years ago. 



About this time, Berzelius discovered selenium,, and 

 was engaged upon the admirable investigation of this ele- 

 ment. Never was there an examination so accurate and tho- 

 roughly exhaustive, of an interesting and hitherto unknown 

 element, comprising all its characters and remarkable com- 

 binations, so that, if we except the discovery of selenic acid 

 by Mitscherlich, which escaped Berzelius, nothing essentially 

 new was added to our knowledge of this element during the 

 next thirty years. Our astonishment at this must be raised, 

 when it is recollected that all these investigations were car- 

 ried on with a very small quantity of material, only about 

 an ounce of selenium, of which quantity a part was lost, 

 owing to the carelessness of a servant. 



This paper upon selenium can only be compared with that 

 by Gay-Lussac upon iodine, which appeared several years 

 before, and has yielded, in so many respects, such valuable 

 results. It must, nevertheless, be remarked, that Gay- 

 Lussac was not the discoverer of iodine, and did not under- 

 take the investigation until after the first chemist of that 

 time, Davy, had almost established the true nature of io- 

 dine ; and that he had large quantities of material at his 

 disposal. 



Almost at the same time that Berzelius was engaged in 

 the examination of the compounds of selenium, Arfvedson 

 occupied himself in his laboratory with the analysis of some 

 Swedish minerals ; and under the guidance of Berzelius, sue- 



