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E. S. Dana — Mineralogical Notes. 



Aet. XL VII. — Mineralogical Notes ; by EDWARD S. Dana. 



1. Columbite from Standish, 3£aine* 



The crystals of columbite obtained a few years since from 

 Standish, Maine, largely through the active efforts of Professor 

 0. D. Allen, are well known for their brilliant luster and per- 

 fection of form. In these respects they are far superior to those 

 from any other known locality. This fact has made it seem 

 worth while to attempt a more exact determination of the crys- 

 talline elements than has been hitherto possible. The material 

 in hand consisted of a large suite of crystals belonging to the 

 Yale College cabinet and that of Professor Brush, and also a 

 number of fine specimens kindly loaned for the purpose by Dr. 

 Greorge H. Williams of the Johns Hopkins University in Balti- 

 more. 



The true form of the species was first established by J. D. 

 Dana, fifty years since, and the axial ratio was determined by 

 him on a crystal from Middletown with considerable exactness. 

 In 1861 Schrauf published his monograph of the species and in 

 it gave a new value of the axes upon the basis of measure- 

 ments of crystals from Greenland and Bodenmais. He also 

 adopted another fundamental form, making w(133 Dana) the 

 unit pyramid. Schrauf's axes have been accepted since that 

 time, although a comparison of his measured and calculated 

 angles shows that the material he worked upon was not suited 

 to give very accurate results. 



Among the crystals from Standish a few were found allow- 

 ing of exact measurement and the angles obtained from the 

 best one of these are given in the following table: 







Calculated. 



Measured. 







Calculated. 



Measured 



530 



530 



530 ) 

 530 j" 



52° 



52' 



j 52° 

 I 52 



42' 

 53 



111 

 111 



111 

 111 



1 



62° 



28' 



i 



62° 20' 

 62 29 



530 

 530 



530 [ 

 530 \ 



127 



8 



j 127 

 I 127 



9 

 14 



111 . 

 Ill 



111 



111 



1 



77 



29 



\ 



77 23 

 77 36 



110 

 110 

 110 

 110 

 130 

 130 

 130 



110 ) 

 110 j 

 110 ) 

 110 [ 

 130 ) 

 130 J 

 130 { 

 130 j" 

 021 



79 



100 



136 



43 

 60 



17 



43 



10 



50 

 40 



j 79 

 ( 79 

 j 100 

 I LOO 

 ]*136 

 I 130 

 { 43 



14 

 18 

 45 

 43 

 10 

 10 

 51 



233 

 133 

 133 

 133 

 133 

 133 

 133 



233 

 133 

 133 

 133 

 133 

 133 

 133 



} 

 1 



\ 



56 



87 



79 

 29 



17 

 36 



54 



57 





29 59 



130 

 001 



} 43 

 60 



49 

 41 



163 

 163 



163 



163 



! 



118 



20 



\ 



118 19 



021 

 001 



021 

 103 



12] 

 19 



20 

 42 







163 

 163 



163 



163 



f 



19 



54 



\ 



19 59 



20 



111 

 111 



Ill J 



108 



43 



j *108 



{ 108 



43 



42 

















* Abstract of an article published in vol. xii of Groth' 

 lographie und Miueralogie. 



Zeitschrift fur Krystal- 



