516 SCIENTIFIC RECORD FOR 1882. 



Researches on other Elements^ etc. 



Thorium. — Two important memoirs have been published by L. F. Nil- 

 son on thorite and its chief constituent, thorium. He worked upon two 

 kilograms of the rare mineral and prepared a very pure thorium sulphate, 

 from which he made a determination of the atomic weight of the element. 

 {See paragraph on atomic weights.) He determined the specific gravity 

 of thoria, finding the figures 10.2199. He also prepared the metal by 

 the reduction of potassio-thorium chloride with sodium in the iron appa- 

 ratus he had previously used for beryllium. The metal obtained formed 

 a gray shining powder showing distinct crystals under the microscope; 

 it is unaltered by exposure to air up to 100-120° C; when heated higher 

 it burns brilliantly, forming a snow-white oxide. The metal burns in 

 chlorine, bromine, and iodine gases, yielding sublimates ; it is slowly 

 attacked by dilute sulphuric acid, and by dilute nitric ; concentrated 

 nitric acid has very little effect. Hydrochloric acid dissolves the metal 

 readily. The metal has the specific gravity of about 11, results being 

 not perfectly satisfactory. {Bcrichte d. chem. Ges., xv, pp. 2519-2547.) 



Properties of Pure Metallic Aluminium. — Prof. J. W. Mallet, in the 

 course of his researches on the atomic weight of this metal, required a 

 quantity in a very i)ure condition, and this gave an opportunity of study- 

 ing its properties. Crude (commercial) aluminium contains: 



Al 96. 89 



Fe 1.84 



Cu trace. 



Si 1.27 



100.00 



This was converted into bromide by treatment with liquid bromine, 

 and the product purified by fractional distillation. It was then reduced 

 by sodium in a crucible lined with a mixture of purified and dried 

 alumina, with sodium aluminate. The metallic globules were again 

 fused and further purified with hydrochloric acid. The metal thus ob- 

 tained was perceiJtibly whiter than the commercial article, also softer, 

 more malleable, and had a fracture with some appearance of fibrous 

 silkiness. Its specific gravity at 4° C. is 2.583. Its specific heat is 

 0.2253 as a mean for the range of temperature 0-100° C. Attempts 

 were made to roughly estimate the fusibility, and the pure metal seems 

 to be a little less fusible than the commercial article. It also presents 

 greater resistance to the prolonged action of solvents — acids and alka- 

 lies — than the impure metal. [Chem. News, xlvi, p. 178.) 



Iridium, according to Mr. John Holland, can be alloyed with phos- 

 phorus at a high heat, and the alloy fuses at a comparatively low tem- 

 perature. The fused metal contains, according to Prof. F. W. Clarke, 

 about 7^ per cent, of phosphorus. The phosphorus is removed by heating 



