218 ANNUAL OF SCIENTIFIC DISCOVERT, 



Hare Minerals. — Ccesiura, from ccesius " sky-coloi'od," owing to 

 two blue lines which it jjroduces in the spectrum ; rul)iclium, from 

 ntbidiis, "dark red," owing to the existence in its spectrum of 

 two red lines of remarkably low refrangibility ; thallium, discov- 

 ered by ]\Ir. William Crookes, which derives its name from thallos, 

 " a budding twig," symbolizing the green tint of budding vegeta- 

 tion ; indium, discovered by Reich and llichter of Freiburg. All 

 of these are due to the introduction into science of a mode of 

 investigation known as the spectrum analysis. 



Position of Thalliiim in Classification. — Mr. Crookes persists in 

 arranging thallium near lead, while Mr. Lamy is equally decided 

 in placing it among metals of the lirst section. In a review of all 

 the facts and considerations in the "Journal of Chemistry and 

 Pharmacy" (Nov., 1865), I have shown the possibility of resolv- 

 ing the question by placing thallium with the alkali metals, but 

 also including with it lead and silver. This opinion confirms a 

 theory brought forward twenty years since by Mr. Baudrimont, 

 who even then ranked lead with barium. Now that we have an 

 alum with a base of oxide of silver, isomorphous with the alum 

 of thallium, that of potassium, etc., there is less objection to put- 

 ting in the same group all these metals, although in other respects 

 they are quite dissimilar. The facts mentioned tend to show that 

 thallium should be considered as establishing a point of union be- 

 tween the alkali metals on one side, and lead and silver on the 

 other. — J. NickRs, in Silliman''s Journal, Jan., 1866. 



Spectrum of Didymium. — Prof. Bunsen has announced a new 

 fact relating to the S2)ectrum of the rare metal didymium. lie 

 has found that when the spectrum of this metal is examined hj 

 polarized light, the position of its well-known black absorption 

 lines varies with the direction in which the light passes through the 

 crystal, — a proof that the position of absorption lines is influencd 

 by the physical structure of the bodies through which the light 

 passes. 



Indium. — Reich and Richter have obtained enough of this new 

 element, to determine its physical properties. It is a white metal, 

 soft, ductile, not easily tarnished, melts at about the same point 

 as lead, and gives a blue color to flame when combined with 

 chlorine or sulphur. Its specific gravity is 7.277, and equivalent 

 37.07, that of hydrogen being one. 



Kaehler has shown that iu the zincblende of Schonfeld, near 

 Sehlaggenwald, the new metal indium is associated with tin and 

 other metals in sufficiently large quantity to be extracted there- 

 from to the extent of several grammes. The blende is calcined ; 

 it is dissolved in sulphuric acid, and the solution is treated with 

 metallic zinc ; the indium is then precipitated, mixed with other 

 metals, which are afterward separated. 



AUoclase. — We learn from "Cosmos" that a new mineral has 

 been discovered at Ora-v icza, in the Banat, to which M. Tschermak 

 has given the name AUoclase. The mineral is composed of sul- 

 phur, arsenic, bismuth, and cobalt, in the mode expressed by the 

 formula Coe As^ Sg, in which it is supposed that one-fourth of ■ 

 arsenic may be replaced by an equal quantity of bismuth. It 



