150 On Columlite. 
Fig. 2. 
= 
Bodenmais, Bavaria. 3. Middletown, Conn. 
1. Haddam, Conn. 
~The specimens from the localities that afforded these two crystals 
are correctly recognized by Dr. Thomson as belonging to the same 
species. A simple inspection of figure 3, a representation of a Mid- 
dletown specimen, seems to lead to the same conclusion respecting 
its relation to the Bodenmais Columbite. ‘This will be rendered more 
apparent by comparing with the above the interfacial angles of this 
I. ‘These angles have been obtained by calculation ; they are 
necessarily founded, en on previous measurements, with which 
they very closely agree.* 
E« 22> 126° 2° a} a (over 0’)=102° 58’ 
Ft, = 136° 36’ aia (over €)=117° 51’ 
P 3 0”=119° 13’ ata (over e)=107° 56’ 
P 3 €=119° 40 0’ 3 Of =150° 17’ 
P ; €=160° 34’ 0” = 0 = T60° 29’ 
Mt €=158° 6 a 3 0/=156° 203’ 
M : e=129° 40’ at e=143° 58! 
MS é=1jS° Si’ 6:t 6"=170° 147" 
M : e=140° 20’ é } e=100° 40’ and 79° 20’ 
In the calculations of these angles, the planes a, were assumed as 
the faces of the fundamental form. We hence obtain for the val- 
ues of the crystallographic axes, a=1.0584=W 1.12, b=1.206= 
“1.454, c=1; and by inspection and calculation deduce the an- 
* The ee values of these angles have been observed by C. U. Shepard, 
Shepard . 
P:a==127° M :e==129° 30", 
Se P: &/==137° 20/2 M:é == 112° 10¢ 
: P : e=160° 23/ 5! : 6/=149° 30' 
M: €==157° 40° a es Me 
