of the Trimetric System. 



47 



TABLE I. 



Angle of Vertical Prism near 90°. 



Vertical 

 Prism. 

 J : J 



I. 



Thoinsonite, - 

 Mesotype, - - 

 Harmotome, - 

 Wohlerite, - - 

 Pyrolusite, - - 

 Andalusite, - - 

 Lievrite, - - - 

 Staurotide, - - 

 Wavellite, - - 

 Olivenite, - - . 

 Libethenite, - 

 Caledonite, - - 

 Chondrodite, - 

 Antimony Glance, 



Do. do. 



Polycrase, - - - 



II. 

 Epsomite, - - - 



Diaspore, 



Gothite, 



Polianite, 



Euchroite, 



Topaz, - - - - - 



Chrysolite, 



Triphyline, 

 Bournonite, - - 

 Do. - - - 

 1 Warwickite, - - 

 ? Lanthanite, 



Macrodome. 

 11 : H 



90° 40 

 91° 



91° 46' 



90° 54' 



93° 40' 



90° 44' 



(f)91° 32' 



(1)93° 8' 



(i) 90° 34' 



92° 30' 



95° 



94° 26' 

 90° 45' 



(21) 



(10 

 (20 



Bracbydome. 

 \i : It 



108° 18' 

 108° 46' 

 108° 48' 

 108° 2' 

 104° 22' 

 109° 6' 

 111° 14' 

 108° 12' 

 106° 14' 



108° 28' 



(20 



(10 



95° 



90° 34' 



93° 52' 



94° 52' 



92° 52' 



92° 8' 



(1) 93° 8' 



94° 3' 



94° 



93° 40' 

 (i 



93°-94° 

 93° 45' 



(10 

 (10 



m 



(li) 

 (H) 



Axes. 

 b 



(10 

 (10 



(£0 

 (10 

 (10 

 (10 

 (10 



105° 8' 



106° 52' 



109° 26'|(*S) 

 88° (10 

 88° 30' (II) 



120° 4' 

 115° 16' 

 113° 6' 

 115° 26' 

 117° 20' 

 115° 22' 

 115° 36' 

 118° 27' 

 115° 

 92° 34' 



(10 

 (10 

 (10 

 (10 



(IT) 



108° 56' 

 109° 42' 

 110° 26' 

 108° 56' 

 107° 54' 

 109° 50 

 112° 40 

 111° 10 

 106° 46' 



110° 50' 



109° 54 



111 4' 



110° 8' 



88° 47 



93° 53 



120° 33' 

 118° 42' 

 117° 30' 

 118° 

 119° 13' 

 118° 10' 

 119° 12' 

 121° 55' 

 118° 14' 

 96° 12' 



0.72253 

 0.71644 

 0.71626 

 0.7261 

 0.77601 

 0.71198 

 0.68429 : 1 

 0.72388 : 1 

 0.75047 : 1 



1.0117 



1.0176 



1.0312 



1.01583 



1.0661 



1.0129 



1.0271 



1.05617 



1.0099 



0.72034 : 1 : 1.0446 



1.0913 

 1.0805 

 1.0132 

 1.0132 

 1.0913 



0.76568 : 

 0.74176 : 

 0.6901 : 

 1.0352 : 

 1.02655 : 



0.57657 : 



0.63398 : 



0.66063 : 



0.6317 



0.6088 



0.63258 



0.6297 



0.59549 



0.63745 



0.95618 



1.01 



1.0699 



1.0888 



1.0513 



1.038 



1.05617 



; 1.0733 



: 1.0724 



: 1.0662 



: 1.0662 



domes are therefore the unit domes. The planes 1 on the eight angles are planes 

 of an octahedron, having for the axes a, b, c, the ratio \a:\b:lc; it is therefore 

 the unit octahedron. 



Taking axis 6 = 1, c = tangent of half the angle /: 1; and a = cotangent of 

 half the summit angle II : 11 These two angles alone are a correct exhibition of 

 the degree of homceomorphism between species; all other angles are dependent 

 upon these, and therefore a long series, for the sake of comparison, although often 

 <riven is not necessary or even desirable. 



° As H is the unit macrodome, so 21 will be a macrodome with the vertical axis 

 twice as long; jf, one two thirds as long; H one half as long; and so on. The 

 first figure or letter in a symbol refers always to the vertical axis a, and the other 

 to the longer or shorter lateral axis, according as it has over it the long or short 

 mark, " or *, 



