FRESH-WATER MUSSELS AND MUSSEL INDUSTRIES. 81 
many patterns, perforated tops for salt shakers, inlaid work, etc. Most or the novelty 
works are located in Muscatine, Iowa. 
The yellow sand-shell, being a rather long, straight-lined shell of peculiar pearliness, 
though not a clear white, is particularly adapted for novelty work, and thus commands 
such a high price that, under normal conditions, no manufacturer can afford to cut 
buttons from it. Shells of this species were often sorted out by the shellers on the river 
bank to be sold at a price two or three times the value of button shells, or from $40 to $60 
per ton. Such shells as were not sorted out, but sold along with less valuable material, 
were subsequently again sorted out by the manufacturer for resale. Practically all of 
these shells were exported to Germany, where they were highly valued. Such shells 
for export sold as high as $90 per ton f. 0. b. New York. 
The Daily Consular and Trade Report of January 6, 1914, stated that there was a 
steady demand in Hamburg for the following grades of American shells, prevailing 
prices c. i. f. Hamburg per 220 pounds being quoted as follows: 
Equivalent 
price per ton of 
2,240 pounds 
$5.95 $60. 58 
4- 76-$13.09 | 48. 47-$133- 37 
II.90- 16. 66 I2I. 16— 169. 63 
Prices of marine shells at the same time were reported as ranging from $7.14 to 
$107.10 per 220 pounds (equivalent price per ton, $72.43 to $1,090.47). 
PROCESSES FOR POLISHING SHELLS.—Polished shells of the iridescent varieties make 
attractive souvenirs or table ornaments.. The polishing may be accomplished by one 
of the following methods, as described by J. B. Southall, shell expert of the Fisheries 
Biological Station at Fairport: 
Buffing process—The outer surface of the shell is ground off by an emery wheel or 
grindstone, the former being preferable, as it grinds much faster. If the surface of the 
shell is grooved, a file is generally used to remove the portions of the surface not touched 
by the grinding wheel. After the outer surface has been removed the shell is polished 
by holding it against a felt polishing wheel revolving at the rate of 2,000 to 3,000 revo- 
lutions per minute, fine polishing paste being applied to the surface of the wheel as 
needed. When all the emery scratches have been removed, the shell receives its final 
polish by holding it against a canton-flannel buffing wheel revolving at the same rate as 
the polishing wheel. If many shells are to be polished a double emery-wheel stand can 
be used to advantage by having the polishing wheel on one end of the spindle and the 
buffing wheel at the other end. 
Chemical process.—If the entire shell is to be polished—that is, the inner and outer 
faces—prepare the shell the same as for buffing. After the surface has been ground off 
the shells are placed in a cylindrical tumbler, using enough water to cover and a reason- 
able amount of fine pumice powder. It usually requires 8 to 10 hours of tumbling to 
remove the emery scratches and smooth the outer face of the shells. After the shells 
are smooth enough they are taken from the tumbler and placed in the polishing machine. 
Polishing machines can be purchased on the market, but a very good home- 
made machine can be constructed at a small outlay. Mount a short piece of 
I-inch shaft in a frame so that the shaft inclines at an angle of 45°, and at 
