86 



BUUvETiN OF THE BUREAU OI? FISHERIES. 



that in the long run the interest of cutter or manufacturer is promoted by waste or 

 antagonism to legitimate improvement. 



PROPORTIONS OP PRODUCT AND WASTE. 



The unavoidable waste in the commercial use of mussel shells is remarkably high, 

 assuming the most economical use possible of materials under present conditions. The 

 waste involved in the combustion of coal is often cited as an example of unavoidable 

 loss, where, under the most efficient methods in use, only a small per cent of the latent 

 energy is converted into power. In button manufacture we find that only 5 to 8 per cent 

 of the original gross weight of the mussel enters into the button product; but the re- 

 mainder in this case is not all lost, since there are waste products which are utilizable 

 at a less profit. In the first place, when the mussel is taken from the river, we find 

 that about 3 per cent of the dry weight is thrown out as meat." The losses in the shell 

 at different stages of manufacture, as determined by averages from several specific 

 tests made by J. B. Southall, are shown in the following table: 



Losses in Shells oi'' Certain Species During Manufacture op Buttons. 



Waste or by-product. 



Discarded shell 



Dust in sawing blank 



Dust in grinding and finishing button 



Total waste or by-product 



Weight of buttons 



Total 



Lake 



Pepin 



jnucket. 



Per cent. 

 60.8 

 16.9 

 12. 9 



9a 6 

 9.4 



Nigger- 

 head. 



Per cent. 



73-6 



8.8 



10.8 



93-2 

 6.8 



Roughly speaking, 7 per cent of the total weight of heavy shells like the niggerhead 

 is marketed from the factory in a form worth $2.16 per pound, ^ while of the remaining 

 93 per cent, a portion is entirely thrown away and another portion sold as crushed shell, 

 or dust, at a quarter of a cent per pound.^ 



The table and data are not of purely academic interest. They point to the signifi- 

 cance of the problem of the utilization of the now unavoidably wasted material, and 

 they emphasize the importance of putting more of the shell into the high-priced 

 product, the buttons. 



It remains to differentiate the instances of waste which are prevented by correct 

 practice in cutting and those which arise from the form or character of the shell, and 

 which consequently may be obviated only by new discoveries in method or by changing 

 demands of the trade. 



WASTE IN CUTTING. 



It may be conceded that there is some waste which it would be possible but 

 not desirable to avoid. Given the present economic conditions, it will appear that 

 parts of the shell which could be cut are better left uncut, because the cost in labor 



a The proportion of dry meat to shell varies widely with the different species. It is safe to say, however, that, on the 

 average, the meats with all water dried out represent one thirty-fifth of the total dry weight of the mussel. The utilization of 

 the meats is discussed in part a, page 6i on the mussel fishery. 



i> Figuring 1,248 buttons to the pound at 25 cents the gross (good quality 16 Une). 



c Price of crushed shell, $5.50 per ton. Price of dust, $4 per ton. 



