304 THE LILIES OF THE FIELDS, ETC. 
above, with the tabular snow-crystals just referred to! It 
exhibits first the regular hexagonal form in its outline, and 
also the two regular triangles corresponding as it were to the 
leaves of calyx and corolla in the lilies of the field! The 
emerald, therefore, is built upon the same fundamental plan 
on which the temple of beauty is erected in the lily ; but the 
material, though beautiful, apparently did not admit of the 
graceful windings exhibited in the more yielding, but also 
less permanent body of the lily of the field. The emerald 
possesses all the AR of form and color which can be ex- 
sss pressed by uniformity of 
material; and if the lily 
of the field surpasses the 
emerald in graceful modi- 
fication of these forms, and 
in variety of color, it lacks 
the lustre of the emerald, 
and even in this very va- 
riety carries the germ of 
speedy decay. There are 
many substances which in 
their crystalline form exhibit the same trinity characteristic 
of the lily, the snow-star and the emerald. The well-known 
quartz, or rock-crystal, exhibits this form, and so does the 
beautiful mineral Alexandrite, represented in Fig. 58. This 
mineral was discovered in the Russian emerald diggings, 9? 
the very day on which the present emperor Alexander be- 
came of age. Ithas furthermore the remarkable peculiarity 
of appearing of a very beautiful green during the day, while 
in the evening (that is by lamp or gas-light) it appears of à 
pure red dr: but red and green are the Russian colors. 
Hence the new mineral was named Alexandrite. 
Even in the animal frame several structures have been 

discovered built upon the same principle, particularly the 
microscopic structure of the retina in the human eye. 
cording to the discovery of the Danish microscopist, Dr. 

