zones had grown at very unequal rates, as shewn in the annexed table49.
| Zone | Increment mm. | ô ô | Zone | Increment mm. |
|---|---|---|---|---|
| Apex | 1ôñ5 | ô ô | 6th | 1ôñ3 |
| 2nd | 5ôñ8 | ô ô | 7th | 0ôñ5 |
| 3rd | 8ôñ2 | ô ô | 8th | 0ôñ3 |
| 4th | 3ôñ5 | ô ô | 9th | 0ôñ2 |
| 5th | 1ôñ6 | ô ô | 10th | 0ôñ1 |
The several values in this table lie very nearly (as we see by Fig. 20) in a smooth curve; in other words a