FRESH-WATER MUSSELS AND MUSSEIv INDUSTRIES. 75 



be obnoxious and injurious to employees (PI. XXXIX, fig. i). Grinders are paid from 

 15 to 25 cents per 100 gross, according to size and thickness of blanks, earning from $9 

 to $15 per week. 



Finally the blanks are again soaked in water to be softened for the finishing machine. 

 In some cases, if too much mixed in quality or size, the blanks may be sorted by hand. 



Making the Buttons. — Having been classified, tumbled, backed, and soaked, 

 the blanks are now ready for the essential processes of button making, which are accom- 

 plished by an automatic machine of comparatively recent invention and of very ingenious 

 design. The illustration (PI. XXXVI, fig. 2) will aid in an understanding of the brief 

 description of the working of the machine which can be here given. (See also PI. XXXIX, 

 fig. 2.) The blanks are fed by hand into depressions in the tops of vertical chucks, which 

 are arranged in series constituting an endless chain. As the chucks in endless chain pass 

 around the circumference of the machine each blank is automatically operated upon by 

 various tools, and each tool is automatically sharpened and prepared for the succeeding 

 blank. The processes accomplished in the machine consist in rounding the edges and 

 carving out the center in the desired pattern to make the face of the button and in drilling 

 two or four holes according to pattern. After the first hole the drill rises, the button makes 

 a turn through a fourth or a half of one revolution (according to whether it is to be a 

 four-hole or two-hole button) , when the drill again descends to make a new hole. After 

 the last hole is drilled the chuck opens automatically to release the button, which is 

 sucked into a tube connected with the blower system to be dropped into a bucket 

 through a counting tube. 



Some twenty-odd distinct operations are combined in the double automatic machine, 

 and it is interesting to record them. Let it be noted that the button travels in an oblong 

 orbit, while the carving tools and the drills, respectively, travel in smaller circular orbits 

 at opposite ends of the button orbit. 



1. The traveling chuck, which is open after releasing a finished button, closes on the 

 new blank placed in the top depression. 



2. The chuck with the blank begins to revolve rapidly on its axis while continuing 

 to travel to the right. 



3. The face of the revolving and traveling button is aplplied to a carving tool of 

 proper form to make the desired face. The tool itself is stationary on its axis, but travels 

 in orbit with the buttons. 



4. The facing completed, the tool rises. 



5. The rotation of the blank is stopped. 



6. The tool, continuing on its orbit, is sharpened on an emery wheel. 



. 7. Before meeting another blank the tool is lowered by a small fraction of an inch 

 to compensate for the shortening due to the grinding on the emery wheel. 



8. The chuck, with its blank, leaves the orbit of the carving tool at a tangent tg 

 pass over to the orbit of the drilling tools. 



9. When the blank is in just the right position, one of the drills descends to make 

 the first hole in the blank. In this operation the drill revolves, while the blank is station- 

 ary on its axis, but both travel together. 



10. The drill rises. 



11. The chuck, with blank, turns through one-fourth of a revolution. 



110306°— 19 5 



