FRESH-WATER MUSSELS AND MUSSEL INDUSTRIES. 89 
attention of many manufacturers and mechanics. Remarkable improvements in button- 
making machinery and systems of management have taken place in recent years. 
Perhaps conspicuous advances in the future may be made, not only in such improvements 
of management and existing machinery as are always to be expected, but in the inven- 
tion of an efficient machine for blank splitting and in the perfection of bleaching processes; 
also in the greater utilization of unavoidable waste. 
In 1912 there were 196 separate plants employing mussel shells in manufacture. 
Of this number 153 plants were devoted to cutting only, while 36 factories engaged in 
finishing and grading. Of these latter 20 included cutting rooms, also, and thus comprised 
all the processes of manufacture. In addition there was a single branch plant devoted 
exclusively to the grading of buttons. There were 34 shell-crushing plants, of which 32 
were connected with button factories, and there were 6 novelty works. ‘These establish- 
ments were located in 20 States as follows: Alabama, Arkansas, Kansas, Kentucky, 
Illinois, Indiana, Iowa, Maryland, Massachusetts, Michigan, Minnesota, Missouri, New 
Jersey, New York, Ohio, Oklahoma, Pennsylvania, Tennessee, West Virginia, and 
Wisconsin. 
The industry is peculiarly American. The material has until recently been obtained 
in no other country, and the machinery and methods are largely of American design and 
development. 
