52 J. D. Dana on the Homeomorphism 








TABLE IV. 
Angle of Vertical Prism, near 120° (1154°-120°), 
Prism Dome Dome Axes 
de li. a iD see 
L 
Sternbergite, - - - - 149° 30" 69° 38’ 100° 2711°4379 :1:1°7147 
i 
Aragonite,- - - - - 116° 10/ 81° 40/ 108° 26’'1°1571 : 1: 16055 
Cerusite,. - .- - =«,-|- 117° 18’ 80° 19 108° 16//|1:1852 : 1: 1:6388 
Witherite, =o ==" -” < 118° 30’ Ti OW 106° 54’/|1°2460 : 1: T6808 
romlite, eer 118° 50’ tpn 107° 6’|1-2504 : 1: 16920 
Stephanite, - - - - 115° 39 85° -5/ 111° 8’/1:0897 : 1 #15844 
BO, ee fon ase = 118° 50 80° 1 © 57’ |1:1861 + 151692 
ysoberyl, - - - =| 119° 46’ (27)78° 54” (x) 109° 387/1-2159 :1: 1-7289 
Discrasite,- - - - -| 119° 59’ 819 29’ 112° 12’ 11633 :1 17315 
opper Glance, - - y Seen hus : H4iHe 
es dion Tae ; 119° 35’ \(gz)88° 56’| 114° 10/.11117:1:1-7176 
Til. 
Herderite,- - - = -} 115° 653’| 1119 49’ 138° sneha 
IV, 
MOE Ge tee ery NS 119° 10’ 94° 121° 38’ 0:9825 :1:1°7033 
| Mica, - 2 + + + =]1199-120° | 





Chrysoberyl is very near Aragonite in angle, if the plane in the 
former usually regarded as 32 be taken as 17, as adopted in the 
table: otherwise the relation for the vertical axes of the two spe- 
cies is that of 3:2. 80 also Copper Glance approaches Arago- 
nite, if what has been taken by authors as 37 be regarded as 17; 
otherwise the relation between them is that of 2:3. Such ratios, 
and if so, 12 in Copper Glance has 61° 54’ for the summit angle, 
and 118° 6/ for the basal; the latter angle is near that of the 
vertical prism. 
prism or unit dome of 115° to 120°; and consequently, if this 
cies in this way, in order to apprehend more fully all the affilia- 
tions and relations of the forms. ‘The author has alluded to 
ausmann’s comparisons fi this method, of the anhydrous sul- 
phates and carbonates; and he would here observe that the gen- 
eral review of Trimetric forms which he has made since his 
ormer paper was printed, and which has been here presented, 
has led him to give more importance to such comparisons 
was implied in his paper in this Journal, vol. xvii, p. 210. 
