An hour after this it was on the banks of the Irtych.

Omsk was now only fourteen miles distant.
The Irtych is a large river, and one of the principal of those which flow towards the north of Asia.

Rising in the Altai Mountains, it flows from the southeast to the northwest and empties itself into the Obi, after a course of four thousand miles.
At this time of year, when all the rivers of the Siberian basin are much swollen, the waters of the Irtych were very high.

In consequence the current was changed to a regular torrent, rendering the passage difficult enough.

A swimmer could not have crossed, however powerful; and even in a ferryboat there would be some danger.
But Michael and Nadia, determined to brave all perils whatever they might be, did not dream of shrinking from this one.