74 BULLETIN OF THE BUREAU OF FISHERIES. 
SPECIES AND Sizes oF SHELL THat May BE ADAPTED FOR DIFFERENT LINES OF BUTTONS. 
Lines of buttons. 
Common name. Species. Remarks. 
Small | Medium | Large 
shells, shells. shells. 
Lines. Lines, Lines. 
Murclketinhs ah Fie gye fore siste vg aie ch oda Lampsilis ligamentina............. 14-18 14-22 14-30 
Yellow sand-shell..............0005 Lampsilis anodontoides........... 14-16 14-20 14-24 | This species usually ex- 
ported for novelty 
work, 
Slough sand-shell..........-6..0005 Lampsilis fallaciosa., ..........60- 14-20 14-20 14-20 
SEC CU Natron kteciejatseisatinietehi ein Lampsilis luteola............+.000- 14-20 14-20 14-20 | Good shell only in cer- 
tain regions, 
WASH DOGNGS Vis ioivin ciciste'cthioniale steldimtastels Quadrula heros:......5.....0.ece0s 14-20 14724 14-40 | Often much waste on 
account of spotting. 
PLELEE-TIA LE. sis Mieieisacs ceielciesie ce ces ola Quadrula undulata 14-20 14-24 14-30 
Niggerhead ..| Quadrula ebenus..... 14-16 14-20 14-24 |) These species yield a 
Maple-leaf....... ..| Quadrula lachrymosa . Be 14-16 14-20 14-24 proportion of irides- 
PHT OIE HACK s oinciseis nies adie menide aor Quadrula pustulosa.............5. 14-16 14-20 14-20 cents. 
Tips are cut from all of the above-named shells. Take, for example, large washboard 
shells yielding 14-40 line blanks. The shells are first taken to the 40-line cutter, who cuts 
out all the 40-line blanks that are of the proper thickness with a true face (PI. XLIV). 
They are then taken to another cutter, who cuts out all the 24-line blanks that are avail- 
able. Finally, they are passed to the tipper, who cuts the remainder of the available 
material into 14 and 16 line tips. These tip blanks when run through the blank classifier 
may turn out a good per cent of blanks that are classed as butts, meaning by this that 
they are thick enough to make into any style of button; the tips are usually so thin that 
they must be finished with a machined face that requires the least material to be taken 
from it. 
At first glance the process of cutting might appear a very simple one, yet it is properly 
an operatiofi requiring much skill on the part of the laborer and the wisest type of 
management. A fuller discussion of the significance of the cutting room in the proper 
utilization of shells is given on pages 82-87. 
FINISHING PROCESSES. 
PREPARING THE BLANKS.—Before going to the finishing machines the blanks are 
usually passed through four intermediate processes. 
The blank classifier is essentially similar to the shell classifier on a smaller scale 
and need not be described in detail (Pl. XX XVIII, fig. 1); by falling between rollers the 
blanks are separated into different lots according to thicknesses (Pl. XX XVII, fig. 2). 
They are then placed in tumblers, consisting of heavy and slowly revolving barrels 
of iron or wood (PI. XXXV, fig. 2). In these the blanks are churned with water and 
pumice stone to clean them and remove the rough edges, making them easier to handle 
and more workable. Lye is sometimes used in connection with the pumice stone. Asa 
cheaper abrasive of more rapid action, fine sand may be used with the pumice stone. 
The blanks are now ready for the grinder, a machine fitted with an emery wheel 
which grinds away the horny backs and reduces the blanks to a uniform thickness (Pl. 
XXXV, fig. 5). These machines are operated by girls, who place the blanks face down 
upon moving belts 3 or 4 inches wide, while the belts convey the blanks underneath 
the emery wheels. These machines, as well as all others that require it, are generally 
connected by suction tubes with blowers for removing the dust that would otherwise 
