FRESH-WATER MUSSELS AND MUSSEL INDUSTRIES. 77 



arises from the fact that the outside, after having been backed, is flat and true, while 

 the inner face may have a natural unevenness. The blank on its back or flat side 

 thus rests more securely in the chucks of the finishing machine and, when finished, 

 both sides are in such true form as desired. 



Assuming each chuck to be properly filled in turn, a machine might finish from 33 

 to 72 buttons per minute, according to the speed given it. Ordinarily the capacity 

 varies from 100 to 190 gross per day. In the days of handwork the output of a single 

 operator in shaping was about 20 gross per day, and the buttons had then to be passed 

 to the driller, who could turn out about 50 gross per day. The cost of a double auto- 

 matic machine in 1914 was about $1,300, with about $300 additional for the feeding 

 attachment, but a machine would probably cost $2,500 in 191 9. The operators are 

 usually women, who were paid, in 1914, i to 2 cents per gross and earned $7 to $11 

 per week. In 19 19 the rate of pay and earnings are 33>^ per cent higher. 



The automatic machine has revolutionized the industry of button manufacture 

 from fresh-water shells. It makes possible not only a far greater yield, but a better 

 uniformity of product than was ever possible with handwork. Something is yet to 

 be desired in the way of lessening the amount of breakage of blanks in process of manu- 

 facture, but the machine is being continually improved and perfected. 



PoiviSHiNG. — From the machine the buttons are taken to the chums, where they 

 are tumbled, or churned, with water and pumice to clean them, take off the rough edges, 

 and make them ready for receiving the final polish (PI. XXXV, fig. i and PI. ^Iv, fig. i). 



The polishing is also a tumbling process, in which, however, sulphuric or other 

 acid is used in conjunction with steam. After the buttons are dried in shakers with 

 sawdust (PI. XXXV, fig. 4), they are placed with dry sawdust and washing powder 

 in a combined tumbler and shaker. This process removes any trace of limy deposit 

 and gives the final luster. Finally the buttons are conveyed in buckets or boxes to the 

 sorting room. 



Sorting. — A very important feature of a button factory is the sorting room, for 

 the qualities and grades can not be sold if mixed indiscriminately. The classifying accord- 

 ing to sizes and thicknesses has already been accomplished in the blank stage, but the 

 grading according to freedom from defects of manufacture or from natural shell stains 

 and with respect to color, luster, and iridescence must be accomplished by the hands 

 and eyes of skilful sorters. Girls are always employed for this work on account of 

 their superior deftness, or quickness of selection, and the most expert sorters can 

 separate the buttons into 12 grades with extreme rapidity. They are provided 

 with a well-lighted room and work seated in rows at long tables before windows (PI. 

 XL, fig. 2). The buttons are handled individually and thrown into series of boxes or 

 drawers arranged about the operator; from 85 to 200 gross of buttons may be sorted 

 in a day, so that sorters might earn, in 1914, from $5.25 to $12 per week, on the basis 

 of pay at one cent a gross. In 1919, sorters are apparently earning from $10 to $19 

 per week on a sliding scale wage of 0.6 to 1.15 cents per short gross according to the 

 number of grades (from 2 to 12) sorted. 



The number of grades varies with the several establishments, but it would not be 

 practicable to enumerate them. Some factories make a specialty of iridescents or 

 shiny-backs, as they were originally called. The iridescents are made from the hinder 

 portion of the niggerhead, pimple-back, and related shells. If a niggerhead shell is 



