nine o'clock
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 . BEVEL SQUARE _ -RSB- `` Now , boys , I want to show you how we can make a fairly good chart simply by the use of this adjustable square , and this will also be of service to us in measuring heights of objects , as well as directing our course . It is now nine o'clock , and you will see that our pole -LRB- A -RRB- throws a shadow to the southwest . Supposing now , we direct the first leg of our journey to that large tree -LRB- C -RRB- , to the west of us . If , now , we put one leg -LRB- D -RRB- of our rule along the shadow line , and the other leg -LRB- E -RRB- along the sight of the line -LRB- F -RRB- , which goes to the tree , we shall find that the distance across between the ends of the bevel square is just two feet . It happens in this case that the tree -LRB- C -RRB- is due west from our observation point ; so we have at nine o'clock each morning a means whereby we can always determine the true east and west . ''