+-------------------+----------+-----------+-------------+---------------+ | Longest dimension.| Number of| 18-line | Quantity | | +-------------------+ mussels | blanks | of blanks | Refer to | |Greater Less | per ton. | per single| per ton. | illustration. | | than-- than-- | | shell. | | | +-------------------+----------+-----------+-------------+---------------+ | 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. | | | | | } | { | | 2¾ 3 | 8,500 | [B]7-8 | }Gradually | {Plate II-- | | 3 3½ | 6,200 | [B]10 | }diminishing| {1st row. | | 3½ 4 | 4,000 | [B]12 | }to less | {2nd row. | | 4 | 3,200 | [B]14 | }than | {3rd row. | | | | | }650 per | {4th row. | | | | | }ton. | { | +-------------------+----------+-----------+-------------+---------------+ [B] At the time of making this table only a few of the larger-sized shells were available, so the estimates of blanks are less accurate. It may be seen from the table that a marketable ton of niggerheads could be composed of the shells of 3,200 or of 33,000 mussels, according as the shells were 4 inches in length or only 1½ inches. As a matter of fact, no marketed ton is ever composed of mussels of an exactly uniform size; furthermore, the extremely large niggerhead shells are very rare and generally not very desirable on account of inferior quality and disproportionate waste. A ton of shells from a region of depletion will also include a number of the smallest and not strictly marketable shells.