88 BULLETIN OF THE BUREAU OF FISHERIES. 
thickness, there will be a quicker return from efforts at propagation of such species and a 
greater likelihood of being able to maintain the supply. 
There will undoubtedly develop a more insistent demand for the best. yielding 
material, causing an advancing price, while the shells which are found to work with less 
economy will decline (relatively) in price to-a point where they can be used with actual 
profit. 
WASTE IN DISCARDED SHELLS. 
A discussion of the general subject of economy would not be complete without 
reference to the discarding of certain classes of shells which have some good qualities, 
but which for one reason or another are not suitable. In the very beginning it was 
thought practicable to use only shells of comparatively uniform thickness. Accordingly, 
muckets and sand-shells were bought, while niggerheads, pimple-backs, etc., were 
refused. It was not long before the excellent qualities of these shells became apparent, 
and it was found practicable to cut them. 
The discards at the present time are almost exclusively shells which could not yield 
buttons for which there is a market. Such are thin shells, colored shells, and shells 
exceedingly stained and spotted; notallof these are wasted. Some pink and purple shells, 
when thick enough, are found to be of a particularly good working quality; they can be 
used for making the smoked-pearl buttons by staining with silver nitrate. The demand 
for such buttons is limited, and, as many pink or discolored buttons are cut incidentally 
and culled from the better grades, there is little actual market for the pink shells beyond 
the limited requirements of the novelty trade. The elephant’s ear.is a rather common 
shell of beautiful pink, purple, or salmon color, and it is said to be superior in working 
qualities to the better grades of white shells. It is unfortunate that a simple, satisfactory 
method of bleaching has not been available or that there is no market for the natural 
pink and purple buttons produced from it. Many discolored, shells may be bleached, 
though somewhat imperfectly, but bleaching methods have been greatly improved in 
recent years. 
The discoloration is generally attributable to disease or parasites. Discolored shells 
seem to be more common in sluggish water and in portions of streams polluted with * 
sewage. : 
RESUME OF MANUFACTURE. 
The fresh-water shells are used preeminently in domestic button mantfacture, 
though a small proportion enters into the producton of novelties, and up to 1914 an 
increasing number were being exported both for novelty and button making. 
The process of button manufacture consists in classifying and soaking or moistening 
shells, cutting (either in detached cutting plants or in a room of the complete factory), 
cleaning, tumbling, backing, and soaking the blanks, facing and drilling (in one or two 
automatic machines), cleaning, polishing, drying and sorting the buttons, and finally 
sewing them upon the cards or packing in bulk. Processes of bleaching and of staining 
may be introduced as desired. 
The principal operations of skill are the cutting of blanks and the sorting of buttons, 
The chief desiderata are the perfection of an automatic cutting machine and the elimina- 
tion of waste as far as practicable at all stages. These needs are receiving the careful 
