284 J. E. Whitfield — Natural Borates and Borosilicates. 



Pandermite, from the island Pauderma in the Black 

 Sea. — The material was hard and compact somewhat resem- 

 bling marble 



H„0 19-40 



B 2 3 48-63 



CaO 32-16 



100-19 



From these figures it will be seen that the priceite and pan- 

 dermite are, in composition, identical, the difference being 

 wholly in the physical appearance of the material, priceite is soft 

 and friable while the pandermite is compact. From the results 

 obtained there is no doubt but that they are the same mineral.* 



Ulexite from Ehode's Marsh, Esmeralda Co., Nevada. — 

 The material for analysis was taken from one of the nodules 

 found in this locality, which on being broken exposed the fine, 

 silky fibers characteristic of the mineral. An analysis gave the 

 following figures. 



Calculated composition. 



Si0 2 



ci : 



B 2 3 



S0 3 



CaO 



Na 2 



0-04 



2-38 



43-20 



0.28 



14-52 



10-20 



45-34 



15-04 



8-83 



KO 



0*44 





H o 



29-46 



30-79 



Deduct O for CI . 



100-52 

 . -53 



99-99 



100-00 



The molecular ratios from these figures are JSTa 2 : CaO : 

 B 2 3 : H 2 0— 16 : 26 : 62: 163, which conform to no simple 

 formula. If, however, we correct the analysis for impurities 

 by throwing out the Si0 2 , the K 2 as KC1, the remaining CI 

 as NaCl and the SO s as gypsum (CaS0 4 . 2H 2 0) we can calculate 

 the composition given above, from which we deduce the for- 

 mula NaCaB 6 9 . 6H 2 0, which lies between the two formulas 

 given by Rammelsberg.f 



Ludwigite, from Morawitza, Banat, Hungary. — The mate- 

 rial consisted of fine, radiating, silky fiber, almost perfectly 

 black, but showing a tinge of violet when freshly broken, very 

 tough when hammered, but easily cut, associated with quite 

 pure magnetite. Analysis gave : 



* Dana's Syst. Min., App. Ill, 97. 



f Pogg. Ann., xcvii, 301. 



