208 Hidden and Hillebrand — Description of Bowlandite. 



is enough to prevent any decided formation of fungus growth, 

 at the same time not enough to cause a deposit as happens 

 when large amounts of hydrochloric acid are used. 



In the titration of tartar emetic in presence of starch the 

 permanent blue color was taken in every case as the indication 

 of the end reaction, as all other shades of color were found 

 unsatisfactory. It is a well known fact that in the titration of 

 antimony salts the color of the starch iodide is not developed 

 until there is a considerable excess of iodine present, so that 

 as compared with arsenious oxide, iodine gives high results 

 with antimony. Thus, for example, the mean of six series of 

 determinations made at various times and aggregating twenty- 

 nine determinations showed the presence of 43'95 per cent of 

 antimonious oxide in tartar emetic. (Sb = 120 and tartar 

 emetic KSbOC 4 H 4 6 . iH 2 . = 332, requiring 43*37 per cent.) 



The facts above shown, that tartar emetic may be kept in 

 stable solution by means of tartaric acid and hydrochloric acid 

 in the proportions given, make it possible to use and keep such 

 solutions for standardizing iodine for the determination of 

 antimony, and thus to eliminate the error due to the tardy 

 development of the starch iodide blue in presence of antimony 

 salts, observed when compared arsenious oxide is used as a 

 standard. 



Art. XXXII. — Description of Howlandite / by "W". E. 

 Hidden and W. F. Hillebrand. 



I. Historical and Descriptive Discussion, by W. H. Hidden. 



About one kilogram of the mineral described in this paper 

 was found by the writer in rather large lumps among huge 

 masses of gadolinite and yttrialite, in a single shipment of the 

 various yttria-bearing minerals, sent to him some five years 

 ago, from the noted locality in Llano County, Texas. 



The alteration products attracted my attention at once by 

 their dissimilarity to those of gadolinite, yttrialite and allanite 

 from the same mine. Several preliminary trials proved the 

 mineral to contain over sixty-one per cent of the " rare earths " 

 having a joint atomic weight of 118 '5. The ignited oxalates 

 had a pale straw color and the absorption spectrum of a satu- 

 rated nitrate solution showed the lines of the erbium and 

 didymium groups very prominent. Ferrous-oxide was found 

 to be present (in one instance estimated at 4*69 per cent) and 

 by the use of ammonium carbonate 040 per cent of what 

 appeared to be uranium oxide was separated from the iron 



