insula; South Australia has at least two hundred and fifty thousand miles unexplored or but little known; and West Australia has fully half a million square miles that have been crossed at intervals by the tracks of a few explorers. In round figures, the extent of unexplored or partially known country in Australia is more than double that of the thoroughly known portion. The continent is almost fairly bisected by the overland telegraph line, which follows closely the track of Macdouall Stuart, the explorer, and the telegraph may be considered a line of demarcation between the explored and unexplored portions."
"And have you ascertained why the continent has not yet been thoroughly examined?" Doctor Bronson queried.
CLEARING IN AN AUSTRALIAN FOREST.
"I have," Fred replied, with alacrity, "and I presume Frank has done so too. It is because there is no water in the interior of the continent, or but very little. If you look on the map you will see very few rivers, and none of those that exist is of great size. Australia is nearly as large as Europe, and see the difference in the rivers. Europe has the Danube, Rhine, Volga, Don, Vistula, Seine, Rhone—all large rivers—together with more than twice as many of lesser note, but all of them important; while Australia has only a single river of consequence, the Murray. There are hundreds of miles of coast-line together where not a single stream, great or small, flows into the sea, and some of the interior rivers dry up and disappear in the hot season."
"I read about that too," said Frank; "the Murray and its tributa-
