122 REPORT OF NATIONAL MUSEUM, 1921. 
In addition to the model there are charts showing some of the inter- 
mediates and finished products obtained from each of the four crude 
chemical materials—sulphur, salt, coal, and atmospheric nitrogen. 
On these charts actual samples of the chemical substances are attached. 
Other features of the exhibit are a collection of American dyes, 
war gases, explosives, pharmaceuticals, synthetic flavors, food colors, 
and perfumes, all derived from coal intermediates, and models to 
show the molecular structure of these chemicals. 
The Bausch & Lomb Optical Co., Rochester, N. Y., presented eight 
specimens of optical glass. These are valuable as indicative of the 
wholly American optical-glass industry which was developed during 
and since the World War. 
Upon request of the Georgetown University School of Foreign 
Service a few specimens of mineral commodities such as Chile 
nitrate, manganese ore, copper ore and copper, raw tin, etc., were 
supplied for illustrative purposes in the classroom. 
The prime object in view for the division since its inception was 
to obtain latitude in depicting the mineral industrial operations and 
their social bearing. But to have concentrated on any one project 
until complete, with the facilities at hand, would have been to 
narrow down the scope of instruction afforded for years ahead. 
It seemed best, therefore, to make the exhibits cover the fields of 
metals and nonmetals inclusively, even though sketchily to begin 
with. Thus the activities were gradually widened so that the total 
number of industries represented at this writing is 22, or about 
one-half of the important types of mineral occurrences. None is 
complete; some depict only the industrial processes; some show 
only the stages from native occurrences to finished product; and 
few deal with the economic aspects, the most difficult and at the 
same time the most important phase of the undertaking. AI] need 
a thoroughgoing attention to arrangement and labeling. In other 
words, the exhibits already assembled need amplifying, and addi- 
tional exhibits are to be obtained. 
