nine o'clock in the morning
DIAGRAM OF THEIR TRIP _ -RSB- On the third day , however , the ground became more level and less broken , the sun appeared , and they felt happy at the thought of getting back again . Thus far in their wanderings they had kept their reckonings , as well as they could without instruments , and that evening the chart was again consulted , as usual . The drawing -LRB- Figure 4 -RRB- shows how it looked with the course of their journey . When they started from the Cataract home at nine o'clock in the morning , they made an observation of the sun , using a vertical pole so as to get the exact direction of the falling shadow . A distant object was then selected , a prominent tree , as far off as possible . The Professor had prepared an adjustable bevel square , which was simply two legs hinged together at one end , by means of a set screw , like a compass . -LSB- Illustration : _ Fig. 5 .