C. Palache — Mineralogy of Franklin Furnace, JSf. J. 179 



on one crystal of zincite from Franklin Furnace, however, 

 which were very satisfactory ; he has therefore calculated an 

 axial ratio based on them and in the following table gives all 

 the measurements made on natural crystals and the correspond- 

 ing angles calculated from (1) the new ratio, (2) Dana's ratio, 

 (3) Traube's ratio based on artificial crystals. The author's 

 measurements were on four faces of the pyramid (4045), the 

 angle to the base (average) being 55° _42 ; with deviation of but 

 4'. A single reading (0001) to (1011) was also obtained, in 

 close agreement. 





Calculated 



Measured 



Angle 



Dana 



a:c = 



1:1-6219 



Tranbe 



a:c= 

 1:1-6077 



Palache 

 1:1-5870 



Dana 



'86 



Grosser 

 '92 



Moses 

 '95 



Palache 





Contact 



Eeflex- 

 ion 



0001/slOll 

 1011^0111 

 0001^4045 

 4045^0445 

 0001^5054 

 5054/^0554 



61°54' 

 52 21 

 56 17 

 49 09 

 66 52 

 54 46 



61°4T 

 52 14 

 56 03 

 49 00 

 66 41 

 54 40 



61°23' 

 52 4)4 

 55 42 



48 48 

 66 25 

 54 33 



65°20' 

 53 53 



55°38' 

 48 50 



55°40' 



54~°42' 



62°00' 

 52 00 



61°22' 



* 



55°42' 



Gahnite, variety Dysluite : Composition. 



Following is an analysis of a gahnite crystal supplied by Mr. 

 Canfield from the locality at Sterling Hill which yielded the 

 enormous crystals in the Canfield Collection. This is the type 

 of the variety dysluite but has not been before analyzed. 

 Specific gravitv 4'56. 



1. Analysis of dysluite, W. T. Schaller, U. S. G. S., 1906. 



2. Same omitting Si0 o , C0 2 and equivalent of CaO, and H 2 0. 

 State of oxidation of iron and manganese not known. 





1 



2 



AlO . 



47-27 



48*81 



Fe O 



9-90 



10-22 



ZnO 



37-10 



38-31 



MnO 



0-93 



0-97 



M^O 



1-09 



1-12 



CaO 



1-01 



0-57 



C0 2 



SiO, 



0-38 



1-47 







H 2 d 



1-21 







•542=1 



Mol. Eatio 

 •478 

 •064 

 •472 ^1 



HI [-528 = l.-04 



•01 j 



100-36 



100-00 



The composition of dysluite is very like that of the gahnite 

 from Franklin Furnace analyzed by Brush, both being very 

 high in zinc. 



