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PROCEEDINGS OF THE NATIONAL MUSEUM. 



Quantitative composition: A sample was submitted to Dr. J. E. 

 Whitfield, of Booth, Garrett, and Blair, of Philadelphia, who re- 

 ported as follows (column 1) : 



The mineral composition, given in columns 2 to 6 inclusive, was 

 obtained as follows : The sulphur trioxide found was first calculated 

 to alunite, E,0.6H,0. 3ALO3. 4SO3, or K, [Al (OH)^]^ (SO,),, the 

 R.O comprising K20:NaoO=approxiinately 3:2. (Columns 2 and 

 3.) The names for the end members are derived according to the 

 standard rule advocated by the writer elsewhere, of assigning a group 

 name (in this case alunite) to the isomorphous series as a whole and 

 naming the (theoretical) end-members by chemical prefixes. The 

 potassium (kalium) end-member thus becomes kalio-alunite, the 

 sodium (natrium) one natro-alunite ; the latter name is indeed al- 

 ready in use, having been proposed by Hillebrand and Penfield in 

 1902.1 



The phosphoric oxide was then assigned in a corresponding 

 way to a molecule with HPO3 replacing the SO, of alunite, 

 R,0.8H,0.3AL03.2P,05, or E,H,[A1(0H),],(P03)„ the same ratio 

 of K : Na being used. That this is the most probable form in which 

 the phosphoric oxide found in alunite and related minerals is present 

 was pointed out by Schaller.^ Although the potassium and sodium 

 salts of this radical are so far known only as isomorphous replace- 

 ments in sulphates such as alunite, they may some day be discovered 

 as independent minerals, and should be assigned names. As pointed 

 out by Schaller, goyazite (hamlinite) is probably a strontium salt, 

 gorceixite a barium salt, plumbogummite (hitchcockite) a lead salt, 

 and florencite a cerium salt of the same radical. If these are all 

 members of one isomorphous series, then all but one of the names are 

 superfluous; one must be selected to apply to the series as a whole. 

 Among them, plumbogummite has priority, having been introduced 

 by De Laumont and Berzelius in 1819, which would make gummite 



1 .\mer. .Tourn. Sci., ser. 4, vol. 14, 1902, p. 220. 



= Journ. Wash. Acad. SoL, vol. 1, 1911, p. 112: Amer. .Tourn. Sci., ser. 4, vol. 32, 1911, 

 p. 359 ; U. S. Geol. Surv. Bull. 509, 1912, p. 70. 



