which is that here quoted.
If bed-plate and slide rest are both equally diminished at each cut, a shell results, with the close part internal. If bed-plate is increased and slide rest diminished, the close part of the shell is external.
SPECIMEN I.—Tools 25, 32, 36; Click-plate 96 or 288.
| Bed-plate moved. | Slide rest moved. | Circles done. | Tool. | |
| 3 | 2 | 12* | (1 done 7 missed) | 25 |
| 6 | 1 | 12* | (1 done 7 missed) | |
| 10 | 3 | 48* | (1 done 1 missed) | 36 |
| 3 | 16 | 24* | (1 done 3 missed) | |
| 23 | 4½ | 4* | (16 done 8 missed) | |
| 29½ | 2 | 96* | 25 | |
| 33 | 1 | 96* | ||
| or 33 | ⅝ | 288* |
SPECIMEN II.—Tools 28, 36; Click-plate 288.
| Bed-plate. | Slide rest. | Circles done. | Tool. | ||
| 1 | ½ | 12 | 28 | ||
| 4 | 1½ | 12 | |||
| 7½ | 2 | 4 | (8 done 4 missed) | 36 | |
| 13 | 3½ | 24 | 28 | ||
| 19¾ | 3½ | 4 | (16 done 8 missed) | 36 | |
| 19¾ | ½ | 4 | (in spaces) | ||
| 21¾ | 1 | 4 | (above last) | ||
| B 17¾ | 1 | 4 | (below last) | 36 | |
| 30 | ½ | 12 | (20 done 4 missed) | 28 | |
| 29⅜ | ½ | 12 |  | ( 1 " 18 " ) ( 1 " 4 " ) | |
| 28¾ | ½ | 12 | Ditto. | ||
| 28⅛ | ½ | 12 | |||
| 27½ | ½ | 12 | | (15 done 4 missed) ( 1 " 4 " ) | |
| 26⅞ | ½ | 12 | | (1 " 18 " ) (1 " 4 " ) | |
| 26¼ | ½ | As before | |||
| 25⅝ | ½ | Ditto. | |||
| 25 | ½ | 12 | (20 done 4 missed) |
From B to here, border, if with 96 click-plate, not good-looking; tool a boring-bit.
| 331/16 | ⅞ | 12 | (7 done 1 missed) | ||
| 319/16 | 13/16th | 12 | (1 " 5 " ) (1 " 1 " ) | ||
| 291/16 | ¾ | 12 | (1 " 1 " ) (5 " 1 " ) | ||
| 279/16 | 11/16th | 12 | (1 " 1 " ) (1 " 5 " ) | ||
| 25¾ | ¾ | 12 | (1 " 1 " ) (7 " 1 " ) |