134 BEPOET OF NATIONAL MUSEUM, 1920. 



the model, a system of circulating water is caused to mine the native 

 salt, bring it in solution to the surface, and finally to surrender it 

 over as required whether coarse and cheap or purified to the last 

 degree of refinement for tahle use. The whole sequence takes place 

 in plain view before the visitor's eyes, while the operatives at their 

 posts about the plant perform their various tasks and the women at 

 their sewing machines stitch up the bags with highly commendable 

 even though perfunctory attention to the work in hand. The plant, 

 in short, is a model plant in every respect, and a fascinating as well 

 as instructive exhibit. 



The other contribution comprising twenty-six large transparencies 

 and upward of six hundred exhibition samples, was donated by 

 the National Lead Company. Several years ago this company 

 undertook to collaborate with the Museum in developing a compre- 

 hensive exhibit to visualize the working of the lead industry and 

 its relationship to public welfare. The progress of the undertaking- 

 has been reported from year to year, and with this latest addi- 

 tion the project, for its consummation, may be said to need only 

 a systematic work of installation under competent technical direc- 

 tion. 



The needs in this direction are not confined to the lead exhibit 

 alone but are in evidence throughout the exhibits in mineral tech- 

 nology. The prime object in view for the division at the outset 

 of its organized activities was to obtain latitude in depicting the 

 industrial operations and their social bearing. Taken with refer- 

 ence to any one mineral industry by itself, such is a large under- 

 taking. The Worcester Salt Company, for instance, had a force at 

 work continuously for upward of five years in the preparation 

 of the salt exhibit; from the time the National Lead Company let 

 the contract for its miniature white lead plant, two years and 

 more elapsed before the contract was fully executed. Work of a 

 similar nature has been done to better advantage under Museum 

 direction but has commonly taken upward of a year: and this 

 visualizing of the industrial operations is not the end point: rather 

 it is but the beginning, the nucleus around which to develop the 

 economic significance of our mineral resources. To have concen- 

 trated on any one theme until complete, with the facilities at hand, 

 would have been to narrow down the scope of instruction afforded 

 for years ahead. Rather, as already stated, it seemed best to make 

 the exhibits cover the field of metals and nonmetals inclusively 

 even though sketchily to begin with. Without dwelling on any 

 one to completion the scope of activities was steadily widened and 

 the addition of the salt exhibit brings the total to twenty. This 

 means that about half of the important types of mineral occurrence 

 are represented. Xone is complete: mostly they go no further than 



