92 PEARLS AND PEARLING 



so they will not be brittle. They are worked up while 

 wet, otherwise they would crumble. The first machines 

 used are the blank cutters, which are hollow cylinders 

 of steel and with diameters corresponding to the sizes of 

 the buttons. One end of the cylinders have fine teeth 

 which saw out the blanks. The cylinders are adjusted to 

 the lathes in which they revolve. The shells are held 

 against the saws with pliers, although some blank cutters 

 prefer to hold the shells with their hands. As the blanks 

 are cut they pass back through the saw and saw holder 

 and drop into a receiver. 



Fig. 25 shows a large Quadrula heros, or "washboard" 

 shell, from which five large button blanks have been cut. 

 The stains on this shell made it difficult to cut more of 

 the large blanks, but some material could have been 

 saved by cutting some smaller blanks from it. After the 

 blanks are cut they are held against a revolving grinding 

 wheel to remove the black epidermis and to make the 

 blank smooth. After this they are turned and the but- 

 tons are given their proper shape. The holes are then 

 drilled in them and they are complete, except for the 

 polishing. This is done by placing the buttons loose in 

 large tumblers where they are subjected to the action of 

 a chemical fluid and mutual contact while the tumblers 

 revolve. They are then washed and dried and sorted 

 into various sizes and grades, and then sewed on cards 

 and packed into cardboard boxes and are ready for 

 the market. Many of the western factories just cut the 

 blanks and send them to eastern factories, where they 

 are finished. Some of the western companies, however, 



