The shells in the fourth and fifth rows, counting from the top in [plate II], are used at the factories when received, and are sometimes particularly favored where the quality is as good as in those from many Arkansas rivers, and the shells will yield two or three blanks of 16 to 20 lines. Such blanks are of a suitable thickness and work up economically besides having a good quality. Some of the shells in these two rows show how blanks of 18, 16, and 14 lines are worked out, a "line" in button measure representing the fortieth part of an inch.
The use of shells taken between 1½ and 2 inches in greatest diameter does not, therefore, like the marketing of those under 1½ inches, represent absolute waste, but it does denote relative waste or real short-sightedness from the economic point of view. Shells of this size will average about 30,000 pairs to the ton, while mussels of such a practical size as 2½ inches will average only 15,000. The number of blanks obtained from a ton of shells of the latter size would be just the same as from a ton of the smaller shells, notwithstanding that only half as many shells are handled. We are thus, when using the smaller shells, depleting the mussel beds at twice the necessary rate without any corresponding advantage.
[WASTE ILLUSTRATED.]
There is given below a [table] that will repay careful examination as illustrating the wastefulness of using the small shells. While the figures must be understood to be only approximate, they are based upon careful weights and counts of a number of shells from several localities. The shells were all "niggerheads" and were all obtained after shipment to factories.
[14]The first two columns show the limits of size for each lot used, the greatest diameter being the basis of measurement.
The third column shows the approximate number of pairs of shells composing a ton, the unit of purchase; multiplying this number by 2 would give the number of single shells per ton.
In the fourth column there is given, in the case of the critical sizes, the number of 18-line blanks readily taken from a single shell (which is one-half the number yielded by a pair of shells, or an individual mussel).
The fifth column indicates the number of gross of blanks, by computation, yielded by a ton of shells. This computation is based upon the cutting of 18-line blanks (not the larger 20-line blanks that have been taken from some of the larger shells in the illustration). Some of these shells are cut excessively close to the tips, on account of taking too many larger line blanks. It must be understood that different sized shells are adapted for different lines of buttons. The data herein is for comparative purposes only.
Table of Sizes, Weights, and Button Production for Niggerhead Shells
(Approximate Figures).
| Longest dimension. | Number of mussels per ton. | 18-line blanks per single shell. | Quantity of blanks per ton. | Refer to illustration. | |||
|---|---|---|---|---|---|---|---|
| Greater than— | Less than— | ||||||
| Inches. | Inches. | Gross. | [Plate I]— | ||||
| ¾ | 1 | 174,000 | 1st row. | ||||
| 1 | 1¼ | 110,000 | 2nd row. | ||||
| 1¼ | 1½ | 55,000 | 3rd row. | ||||
| 1½ | 1¾ | 33,000 | 2 | 917 | 4th row. | ||
| 1¾ | 2 | 26,000 | 3 | 1,008 | 5th row. | ||
| 2 | 2¼ | 20,000 | 4 | 1,111 | 6th row. | ||
| 2¼ | 2½ | 15,000 | 5 | 1,042 | 7th row. | ||
| 2½ | 2¾ | 10,500 | 6 | 875 | 8th row. | ||
| } | Gradually diminishing to less than 650 per ton. | { | [Plate II]— | ||||
| 2¾ | 3 | 8,500 | [B]7–8 | 1st row. | |||
| 3 | 3½ | 6,200 | 10 | 2nd row. | |||
| 3½ | 4 | 4,000 | 12 | 3rd row. | |||
| 4 | 3,200 | 14 | 4th row. | ||||