(c) Prejevalsky found that the name of Lob-nor was not applied to either of his lakes, although, from the inquiries of Shaw, Forsyth, and others, it is well known far and wide. But he met with it, evidently without learning its exact meaning, at that part of the Tarim to the east of which the true Lob-nor must lie.
(d) Concurrent historical notices on the former trade-routes from China to the west point with certainty to the conclusion that the region of the true Lob-nor was undisturbed by them, and that they crossed much farther to the south and west of Khas-omo, so that there, and not at Lob, lie the kingdoms of Leulan, Shen-shen, &c., which are named in history as situated near "the salt-lake."
(e) A last and weighty argument is furnished by the only hydrographical measurements taken by Prejevalsky of the rivers observed by him. Taking the fathom at six feet he found:—
| Breadth in feet. | Depth in feet. | Velocity of current. | |
|---|---|---|---|
| 1. Koncheh-daria | 42-60 | 10-14 | ? |
| 2. Inchikeh-daria | ? | ? | ? |
| 3. Ugen-daria | 48-60 | ? | ? |
| 4. Tarim, at the mouth of Ugen-daria | 300-360 | 20 | rapid |
| 5. Tarim, below the confluence of all its feeders | 180-210 | 21 | moderate. |
| 6. Tarim, between the two lakes | 125 | 14 | 170 feet per minute. |
It appears, then, that the united river only brings down a part (probably less than half) of the aggregate volume of water contained in all its branches. Even at the time of the greatest summer heat, such a diminution, owing to excessive evaporation, would be difficult to explain; but since the observations were made in winter, when the temperature during the day never rose above freezing-point, and at night fell below zero Fahr., evaporation could have nothing to do with it.
