Chemical Notices :~-M. Lamy on the new Metal Thallium. 185 



inhabited town. The above experiments do not claim to have 

 obtained a determinate ratio for the quantities of the obscure 

 heat-rays which have passed through the different media of the 

 eye, it is merely shown that a quantity of obscure rays which 

 can be detected by our thermoscopes can reach the retina. 



XXVI. Chemical Notices from Foreign Journals. 

 By E. Atkinson, Ph.D., F.C.S. 



[Continued from p. 30.] 



THE following account* has been given by M. Lamy of his 

 investigations on the new metal discovered by Mr. Crookes. 



In examining, three months ago, with Kirchhoff and Bun- 

 sen's spectrum-apparatlus, a specimen of selenium which my 

 brother-in-law M. Ered. Kuhlmann had extracted from the 

 deposit of the chamber in which sulphuric acid is prepared by 

 the combustion of pyrites, I perceived a well-marked green ray, 

 which I had not perceived in any of the numerous simple or 

 compound mineral bodies which I had studied. I was at that 

 time ignorant that an English chemist, Mr. Crookes, had not 

 only discovered the same green rays under almost analogous 

 circumstances, but had given the name thallium to the new ele- 

 ment, from the Greek word 0<z\\o?, or the Latin thallus, fre- 

 quently employed to express the rich tint of a young and vigo- 

 rous vegetation. With great sagacity^Mr. Crookes had indicated 

 some reactions of the element, which he considered as a metalloid, 

 belonging probably to the sulphur group ; but the small quan- 

 tity of the element on which he had worked had not enabled him 

 to isolate this element and distinguish its true nature. 



On my part, I tried to isolate the new body, seeking it in the 

 sediment of the lead chambers, from which had been extracted 

 the selenium that gave the characteristic green line to the spec- 

 troscope. This line naturally served as guide in my researches, 

 and permitted me to arrive at the preparation of perfectly defi- 

 nite crystalline compounds, from which, with the aid of the pile, 

 I extracted thallium for the first time. 



Properties of Thallium. — Thallium has all the characters of a 

 true metal, and in most of its properties greatly resembles lead. 

 Somewhat less white than silver, its fresh section presents a 

 bright metallic lustre. It appears yellowish when rubbed 

 against a hard body; but this tint is doubtless due to an 

 oxidation, for the metal which has been precipitated by the 

 battery from an aqueous solution and melted in a current of 

 hydrogen is white, with a bluish-grey tint, like that of aluminium. 



* Comptes Rendus, June 23, 18G2. 

 Phil, Mag. S. 4, Vol. 24. No. 160. Sept. 1862. O 



