| No. of stake. | Inches. | |
| 1 | moved | 41/2 |
| 2 | " | 81/4 |
| 3 | " | 91/2 |
| 4 | " | 9 |
| 5 | " | 81/2 |
| 6 | moved | 71/2 |
| 7 | " | 61/4 |
| 8 | " | 81/2 |
| 9 | " | 7 |
| 10 | " | 51/2 |
The width of the Glacier de Léchaud at this place was found to be 825 yards; its maximum motion, as shown by the table, being 91/2 inches a day. This is the slowest rate which we observed upon either the Mer de Glace or its tributaries. The width of the Talèfre-branch, as it descends the cascade, or, in other words, before it is influenced by the pressure of the Léchaud, was found approximately to be 638 yards.
SQUEEZING AT TRÉLAPORTE.
The widths of the tributaries were determined for the purpose of ascertaining the amount of lateral compression endured by the ice in its passage through the neck of the valley at Trélaporte. Adding all together we have—
| Géant | 1134 | yards. |
| Léchaud | 825 | " |
| Talèfre | 638 | " |
| Total | 2597 | yards. |
These three branches, as shown by the actual measurement of our 5th line, are forced at Trélaporte through a channel 893 yards wide; the width of the trunk stream is a little better than one-third of that of its tributaries, and it passes through this gorge at a velocity of nearly 20 inches a day.
THE LÉCHAUD A DRIBLET.
Limiting our view to one of the tributaries only, the result is still more impressive. Previous to its junction with the Talèfre, the Glacier de Léchaud stretches before the observer as a broad river of ice, measuring 825 yards across: at Trélaporte it is squeezed, in a frozen vice, between the Talèfre on one side and the Géant on the other, to a driblet, measuring 85 yards in width, or about one-tenth of its former transverse dimension. It will of course be understood that it is the form and not the volume of the glacier that is affected to this enormous extent by the pressure.
Supposing no waste took place, the Glacier de Léchaud would force precisely the same amount of ice through the "narrows" at Trélaporte, in one day, as it sends past the Pierre de Béranger. At the latter place its velocity is about half of what it is at the former, but its width is more than nine times as great. Hence, if no waste took place, its depth, at Trélaporte, would be at least 41/2 times its depth opposite the Pierre de Béranger. Superficial and subglacial melting greatly modify this result. Still I think it extremely probable that observations directed to this end would prove the comparative shallowness of the upper portions of the Glacier de Léchaud.