70 BULLETIN OF The BUREAU OF FISHERIES. 



Most of these processes have become obsolete in the United States with the devel- 

 opment of modern machinery. It is, indeed, to the automatic machinery that the 

 industry owes its present relative importance. The old process of sawing remains prac- 

 tically unchanged, but the grinding, facing, and drilling, the principal features of button 

 making, are accomplished by automatic machinery. For the three processes either 

 two or three machines are used; in some cases a grinder attachment to the double auto- 

 matic makes it possible to combine the entire process in one machine. 



The sorting, or grading, of the buttons requires nice judgment and must still re- 

 main a hand process; but recently a machine has been introduced for the attachment 

 of buttons to the cards. 



Not only the departures in the mechanical equipment but the improved efl&ciency 

 of labor and better shop management are combining to increase the output and to 

 promote economy of production with better quality and uniformity of product. These, 

 and such other present-day features as the utilization of waste materials and the intro- 

 duction of sanitary devices, will undoubtedly be more generally and effectively applied 

 in the future. 



PROCESSES OF MANUFACTURE. 



The description of the general process of button making as given below is essen- 

 tially that of the average modern plant, although in each factory characteristic modifi- 

 cations of method are encountered. 



PRE'PARATION OF SHELLS. 



Storage. — ^When the mussel shells are received by barge or freight car, they are 

 hauled to large covered or exposed storage bins at the factories, to be kept until ready 

 for use. A rough sorting is often done at this stage, so that each bin will contain shells 

 of a rielatively uniform size and quality. There is no apparent deterioration of the 

 quality of shells if protected from the weather. If not so protected, they are liable in 

 time to lose the luster and become lifeless or chalky. The exterior of the shell is most 

 readily affected once the horny covering is worn or scaled off. For this reason shells 

 which have been long exposed on the banks or "dead" shells from the rivers are consid- 

 ered undesirable. 



Classifying — ^When the shells are taken from the bins for use, they are first 

 sorted by hand according to species or quality of material, if this has not previously 

 been done, and are then classified as to size. The latter process is accomplished by 

 a machine called a classifier, which, though larger, is similar in principle to the classi- 

 fier used for blanks (PI. XXXVIII, fig. i). The shells are put into a large hopper, from 

 which automatically they are fed slowly onto an endless belt leading to the classifier, which 

 consists, primarily, of two hollow metal rollers about 6 inches in diameter and 8 feet 

 in length. By falling between the two rollers the shells are to be separated, roughly, 

 into four or five grades, according to size and thickness. To this end the rollers are 

 set with an incline and are not quite parallel with each other, being more widely sepa- 

 rated at the lower ends. As they revolve outwardly the shells slip, or roll down the 

 incline to a point where the opening between the rollers permits them to fall into one 

 of a series of buckets placed below. The smaller and thinner shells are found in the 

 buckets nearest the head. 



