28 Bulletin of Laboratoj'ics of Don son Univcisity iv.>i. xii 



crepancy in these two constituents is easily accounted for, 

 however. The SiO^ is increased by the presence of finely 

 divided mineral particles from the granite and hyalite, it being 

 quite impossible to effect a complete separation of the urano- 

 phane from these two. The amount of available material was 

 so small that it was impossible to separately determine the com- 

 bined and uncombined water, and under the total water given 

 in the analysis, it is reasonable, at least, to assume that a small 

 fraction of it is hygroscopic (uncombined) water. What now 

 appears then as a slight variation from the exact formula for 

 uranophane, disappears when the above facts are considered. 



A comparison of the above analysis of the Georgia min- 

 eral with several by Genth and von Foullon of the uranophane 

 from Mitchell County, North Carolina, and one from Kupfer- 

 berg. Silesia, quoted by Dana,^ shows very close agreement. 

 The reported occurrence of uranophane in granite at Kupfer- 

 berg in Silesia appears in this particular to be similar to that in 

 Georgia. 



Geological Laboratory of Denison University, 

 Granville, Ohio. 



iQp. cit. 



