VALUE AND USES OF SHELLS 91 



value of the shells they gather and the weather, and 

 their luck in finding slugs, baroques and pearls. 



There is quite a difference in the values of shells. In 

 rivers near the Iowa markets, the freight rate is lower 

 than in the more remote districts. Some rivers have fine 

 shells, but are too far away from the market to be 

 worked profitably. In some instances this difficulty can 

 be overcome by building a barge and installing machines 

 for cutting blanks. In this way the shells are worked 

 up into blanks, while the small floating blank factory 

 gradually drifts toward a favorable shipping point, where 

 the blanks are shipped to the nearest button finishing 

 plant. The plan is a good one. 



It is important to know just what the button manu- 

 facturers need for button material. The requirements 

 are a white shell with the whiteness uniform throughout 

 the various strata of the shell ; a bright pearly nacre ; a 

 degree of toughness that will allow the shell to be worked 

 up without cracking or splitting ; and a size and shape 

 and smoothness that will allow the shell to be used with- 

 out much waste. 



As the principal use of shells is in the manufacture 

 of buttons, a brief description of the evolution of pearl 

 buttons will probably be of interest to pearl hunters and 

 shell gatherers. 



The mussels are first cooked and then the meat is re- 

 moved. The cleaned shells are then shipped to the fac- 

 tory and stored in sheds. They are then sorted into dif- 

 ferent sizes and soaked in water from three to six days 



