out, when we weigh our anchor. We commence our cruise with a long turn to windward down the bay. On scanning our chart we note that extensive shoals, whose edges are marked by buoys, hem in the navigable channel on either side, and that we have to keep the conical buoys on our port hand and the flat-topped on our starboard, in order to avoid running aground. So we take care not to stand on too long on either tack, but go about in time, keeping well within the warning marks; and, at last, having got clear of all dangers, we are well outside the bay, in deep water, at some distance from the land, but with the landmarks on shore still clearly visible.
Now is the time to take our departure, as it is called; that is, we will determine, before losing sight of land, our exact position, noting the time of the observation. It is from these data that we shall make our future calculations to ascertain our position, when on the open sea, with no land in sight. There are various ways of taking a departure. In the present instance we will take it by cross-*bearings. On looking back towards the coast we perceive two well-known landmarks which are indicated on our chart—the lighthouse at A and the church at B. With the compass we take the bearings of these and find that A bears S. by E. of us, and B W.S.W. Our compass has no deviation, else we should now have to correct these bearings according to the rules already explained; and as the compass design on the chart is magnetic and not
