(110 ) 
Woods and Wood Products. Cases 181 to 195.—The 
great number of useful woods and their more important 
products precludes anything like a complete representation 
of those of the entire world, with our present means and 
equipment, although it is not improbable that such an 
exhibit may be undertaken inthe future. Inthe meantime, 
the collection will be found to contain much of interest 
and value, and will be extended as our facilities permit. 
Charcoal. Case 196.—Charcoal is the residue remaining 
after driving off the volatile constituents of wood, both 
those which exist naturally in it and those which are formed 
during the application of heat, oxygen being excluded to 
avoid the burning of the carbon. Although charcoal is 
chiefly employed as a fuel, it has many other important 
uses, different sorts being specially applicable for certain 
of them. One such use isin the manufacture of gunpowder, 
for which purpose the carbon must be free from silica, or 
other crystals capable of causing sparks by friction. 
Another use requiring very special properties is that for the 
carbons of incandescent electric lamps. Certain kinds of 
charcoal are specially useful in medicinal preparations. 
Our collection of these products is at present very small, 
but is nevertheless of considerable interest. 
Miscellaneous Specimens. Case 197.—In this case will 
be found a number of interesting articles not properly 
referable to any of the special classes above enumerated, 
ornaments and toys being specially prominent. Many 
seeds and other plant parts are employed in the making 
of beads and decorative articles. The ivory nut, the very 
hard seeds of a species of palm, is largely used in the 
making of buttons, chessmen and various carved articles, 
substituting ivory for such purposes. This collection is 
capable of indefinite extension as a result of visits to countries 
inhabited by savages and other primitive peoples. 
North American Dendrology. Cases 199-264.—The col- 
lection of North American Dendrology is based on speci- 
mens of the wood of all North American trees. To the 
