458 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



throws down an oxide, and that it was easily reduced before the 

 blow-pipe to a metallic bead, A second paper by the same authors 

 appeared November 16, 1863. In this the position of the lines 

 on the scale was more fully defined. If the soda line was at fifty, 

 and strontia at 104, then the two indium lines would be at 110 

 and 147. A pure salt of indium in the flame of a gas-burner or 

 alcohol lamp, imparts a violet color. They also found that the 

 source of the metal was the blende, and were able to recover 0.1 

 per cent, indium from metallic zinc. 



A third paper, October 7, 1864, gives us further properties. 

 The oxyd is easily reduced by hydrogen gas the same as the oxyd 

 of copper, and can be melted to pellets in a glass tube. The 

 hydrogen gas, after passing over the metal, burns with a blue 

 flame. The metal is white, brighter than tin, approaching the 

 luster of silver. It is very soft and ductile, and retains its luster 

 ii^. the air and in water, even in boiling water. Its specific gravity 

 was found to be 7.17, on three determinations ; according to 

 Winkle it is 7.36. The point of fusion is the same as that of 

 lead. Its oxyd does not appear to color glass. It is soluble in 

 hydrochloric and sulphuric acids with evolution of hydrogen gas; 

 is also easily soluble in nitric acid. It is completely precipitated 

 from acid solutions as a hydrated oxyd by ammonia and potash, 

 insoluble in an excess of the reagent; the principal distinction 

 from zinc and cadniiuni. The hydrated oxyd is pure white, and 

 peculiarly slimy, on which account it adheres to the sides of a 

 vessel. Tartaric acid prevents the precipitation of the oxyd. 

 The oxyd after heating and cooling, becomes of a straw-j^ellow 

 color. Sulphuretted hydrogen does not precipitate any material 

 amount of the metal from strongly acid solutions. The behavior 

 is like zinc in this respect. From solutions in acetic acid sulphur- 

 etted hydrogen throws down a beautiful yellow sulphide of indium, 

 recalling sulphide of cadmium, and this aflfords a method of sepa- 

 ration from iron and manganese. 



The chloride of indium resembles chloride of aluminum and 

 can be prepared in the same way, by passing chlorine gas over 

 the oxyd, mixed with carbon. It is very hygroscapic, and can be 

 driven from one place to another in the tube. The sulphate 

 crystalizes in small white scales. 



The atomic weight is 37; according to Winkler, 35.9. 



The preparation of indium from blende is as follows : The 

 blende is digested in oqua rerjia^ and sulphuretted hydrogen 



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