232 Intelligence and Miscellaneous Articles. 



accommodate itself to the diminishing angular velocity on account 

 of the increasing viscosity of the mass. Hence, since that time the 

 theoretical ellipticity of our planet must have been found smaller 

 than the geodetical one ; and the discrepancy must have increased 

 to this date, to increase still more with the centuries to come. 



Comparing the actual ellipticity with that given by our equation 

 [a], we have a new method for investigating the physical conditions 

 of planets, and the retardation of their diurnal rotations. 



Philadelphia, June 7, 1884. 



BY MARTIN WEBSKY. 



In a dense bright yellow ore, consisting essentially of zinciferous 

 vanadate of lead, found in the Aquadita mine in the province of 

 Cordova, La Plata, which is found among the minerals brought by 

 Professor Brackebusch from Cordova to Europe, I have detected the 

 presence of a new element allied to vanadium. 



If the red metallic acid removed by mercuric nitrate and isolated 

 by heating be treated with caustic ammonia it dissolves, but at 

 first leaves a bright yellow residue, which goes into solution, though 

 more slowly. 



The first portion of the solution contains almost exclusively 

 vanadic acid, and, when mixed with a little ammonium sulphide, 

 after a short time black flecks of vanadium oxide. 



The subsequent portions give, when mixed with a little ammonium 

 sulphide, after a short time, far more rapidly, purple-red flecks. 



The occasion for this experiment was the unusual phenomena 

 observed in the formation of a precipitate resembling silver chloride, 

 and which probably contains this substance ; this was met with 

 when, for the purposes of a chlorine determination, the aqueous 

 extract of the soda-smelt of the ore was mixed with silver nitrate 

 and nitric acid, and in still greater quantities on evaporating the 

 second filtrate with hydrochloric acid. After trying a series of 

 suitable and also of some unsuitable processes, the precipitate was 

 found to contain the silver salt of a new metallic acid, which was 

 finally found in the yellow higher oxide, as well as in the lower red 

 one in small quantities. 



The new body, to which I assign the name of Idunium, is remark- 

 able for resistance of the silver salt of the higher oxide against 

 reagents, but resembles in its general analytical reactions vanadic 

 acid ; in the analytical separation when the latter passes into solution 

 in salammoniac, the idunic acid remains in the mother liquor, and on 

 the addition of ammonium sulphide it becomes red and deposits 

 red idunic oxide. — Berlin Sitzungsberichte, June 19, 1884. 



