122 REPORT OF ^^ATIONAL 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 noimietals 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. All 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. 



