Dr. North on the Binocular Microscope. 61 
The feathers most in demand for this purpose are from a beau- 
tiful species of Alcedo, brought from the tropical regions of Asia; 
they are employed for silver articles. King-fishers of coarser plu- 
mage, and less brilliant hue, found throughout the country, are 
used for ornaments made of copper or pasteboard. Blue always 
greatly predominates over lighter or darker shades, relieved by 
purple, white or yellow. 
Whether Aztec silversmiths, whose ingenuity is so much laud- 
ed by the old Spanish chroniclers, practised this branch of plu- 
magery or not is uncertain, There is reason to believe that what 
is said of their imitation of animals with moveable wings or 
limbs, of their representing scales of fish alternately of gold and 
silver, were nothing more than what is now done by the same 
craft in China; and which were esteemed very marvellous by Sir 
J. Mandeville (Voiage and Travaile), motion being communi- 
cated by wires and springs, and colors imparted by the plumage 
of choice birds. 'The construction of automata proper requires 
a knowledge of horological mechanism, never attained by either 
Chinese or Aztecs. Plumagery doubtless attained a far higher 
degree cf excellence in Central America than in China, owing to 
the greater variety and extreme abundance of the feathered tribe 
in the dense and luxuriant forests of Mexico. Yet it is not like- 
ly that feather fabrics were so easily manufactured as to be worn 
by other than the nobles and affluent, to whom in China their 
use was confined. Had the Chinese been as destitute of textile 
fabrics as the Aztecs, they would unquestionably have engaged 
in plumagery with greater success. 


Arr. VIIL—Binocular Microscope; by Dr. E. D. Norru. 
eyes, two drawings or photographs at the same distance are seen 
and are united by the brain, as if both eyes were looking at a 
single solid object without the intervention of an optical instru- 
ment. The success of the stereoscope may be pronounced per- 
of two drawings affords the same amount 

