80 REPORT OF NATIONAL MUSEUM, 1918. 



ing of gold has been enriched by the development of a large pano- 

 ramic model measuring 11 by 14 feet, showing the occurrence and the 

 various methods — lode mining, hydraulicing, dredging, panning, 

 and the like — employed in winning the metal. 



In the copper series notable progress is to be recorded, too, in the 

 completion of the magnificent panoramic model of the Bingham 

 Canyon mining operations in keeping with its inspiring magnitude 

 of mountainous scope and setting. The lead series affords } T et another 

 important instance of progress during the year. The model designed 

 to show the operations of lead manufacture, and in part placed on 

 display upward of a year ago, has been completed and stands in 

 the exhibition halls a miniature manufacturing plant complete in 

 every detail of operation, in proportions of one-twelfth those of ac- 

 tual practice. Various supplementary features in this series, such as 

 a wall panel on which are sketched the various operations of the plant 

 in their sequence, a series of transparencies of the actual operations 

 themselves, and various other features have also been under prepara- 

 tion during the year. 



Five lines of investigation having a special bearing on the present 

 emergency of war have been developed within the division in the 

 course of the year, comprising fertilizer materials, sulphur, coal 

 products, power, and petroleum. These are subjects, however, which 

 have been under consideration for several years in connection with 

 the assembling of exhibits. Thus the work has a tw T ofold aspect, that 

 of its emergencj' application in war, and that of its enduring applica- 

 tion in connection with the normal activities of peace. 



The work found its occasion in the effort to be of service in the war. 

 In mobilizing the economic forces of production and filling in their 

 gaps, the country has faced a task fully as necessary as that of effect- 

 ing the requisite military organization, and equally as intricate. 

 The difficulty in building up deficiencies as they become apparent 

 lies in the complexity of interrelationship. This is especially true 

 among the chemically conducted industries. In the first place there 

 is the group relationship of progressive segregation, most notably 

 instanced in the coal product series, wherein the isolation of any one 

 product entails the work leading to the isolation of many others. 

 Then comes the group relationship of recombination into usable 

 form, as in the case of fertilizer manufacture, where an entirely dif- 

 ferent basis of interdependence is established drawing variously 

 upon the other groups and linking them together. Thus it comes 

 that to build up a deficiency in any one specific direction it com- 

 monly proves necessary to carry the work of reconstruction far afield.. 



This question of interrelationship, as applied to mineral deriva- 

 tives, has been a subject of special study in the division from the 

 time of its establishment, and it was felt from the outset that here 



