148 RE-EXAMINATION OF AMERICAN MINERALS. 



yttria is replaced by the oxide of cerium ; the formula repre- 

 sented by the analysis is, however, the same, namely : (T, Ca) 3 ?. 

 Great care was taken in the separation of the oxide of cerium, 

 which after being peroxidized by heat yielded but little to dilute 

 nitric acid, indicative of the presence of but a small quantity 

 of the oxides of lanthanum and didymium. 



42. Lanthanite. 

 This mineral was first observed in America by Mr. W. P. 

 Blake, and described in the American Journal of Science and 

 Arts, September, 1853; it was obtained by Mr. Blake from 

 Bethlehem, Lehigh County, Pennsylvania, where only one 

 specimen had been found. It was handed to me for exami- 

 nation, and ascertained to be carbonate of lanthanum ; the 

 analysis made was given in the original description of the 

 mineral. Since then I have made another analysis on a portion 

 remaining in my possession ; and, although not differing from 

 the former one, it is thought proper to insert it in this paper. 



1 2 



Water 24.21 24.09 



Carbonic acid 21.95 22.58 



Protoxide of lanthanum (with some oxide of didymium) 55.03 54.90 



101.19 101.57 

 No. 2 is the analysis already published in the paper before 

 mentioned. In both instances there was an excess, owing to 

 the peroxidation of a portion of the lanthanum — a circum- 

 stance that can not be avoided, nor do we know how to allow 

 for it in our calculation. This mineral has the same formula 

 as the artificial carbonate, namely, La C4-3H= carbonic acid 

 21.11, oxide of lanthanum 52.94, water 25.95. 



The only other known locality of this mineral is Bastnas in 

 Sweden ; it is there found only as a coating to cerite, and 

 doubtless was not obtained in a perfectly pure state by Hisinger, 

 who gave as its formula La 3 C+3K. I have no doubt as to the 

 minerals being identical, and that whenever the Bastnas variety 

 is obtained crystallized it will prove to have the same compo- 

 sition as the Bethlehem variety. 



43. Mangano-magnesian Alum from Utah. 

 This alum was observed a few years ago by Dr. G-ale among 

 specimens brought from the Salt Lake, in Utah, by Mr. Stans- 



