84 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



Indeterminate. 



CBYSTAXLOGEAPHIC PKOPEETEES. 



CHEMICAL PROPEETIES. 



Qualitative tests: Before the blowpipe gives reactions for Al, Na, 

 SO3, and HgO ; in HCl slightly soluble, the solution giving faint reac- 

 tions for Al and SO3 ; after ignition, H2O extracts Na2S04. 



Quantitative composition: Tlirough the kindness of Prof. F. W. 

 Clarke, chief chemist, two analyses of this material were made in the 

 laboratory of the United States Geological Survey by E. K. Bailey. 

 The material from near the surface gave the results in column 1, that 

 from a depth of 60 feet those in column 5, below : 



In the determination of the mineral compositions, the sulphur tri- 

 oxide was first calculated to alunite, with Na : K in the first = approxi- 

 mately 5 : 2 ; in the second 9:1. The remainder contains in both cases 

 Al^Og : SiOa^about 4:5, which indicates a clay belonging to the allo- 

 phanite group ; the alkalies left over may be adsorbed in this clay, or 

 may be present in combination in a feldspar or other silicate, but 

 the microscope fails to yield definite evidence on this point. 



The specimens from California contain thus over 50 per cent of 

 natroalunite, with small amounts of kalioalunite and a rather large 

 amount of impurities. 



A LITHirrM-BEAEING PSILOMELANITE EKOM TENNESSEE. 



A manganese dioxide, forming a coating on vein quartz, sent to 

 the United States National Museum for examination and report by 

 Mr. J. B. Lawson, of Sevierville, Tennessee (U.S.N.M. Cat. No. 

 87371), has proved to be so unusual in composition (approaching the 

 variety which has been called lithiophorite), as to be worth special 

 description. Mr. Lawson states that it occurs " loose in the soil in 

 the vicinity of the proposed Appalachian Park." Its properties are 

 as follows: 



