Most of our surveying was done by actual measurement, the surveying instrument being used only to determine the exact direction of the measurement.  However, there were some measurements which we could not make directly with the chain.  For example, we wished to know just how far it was from our tent to the Jersey shore of the river.  We measured off a base line along our shore 400 feet long and sighted to a point directly across the river from our tent.  The angle in front of our tent was 90 degrees, and at the other end of the base line was 73 degrees.  When we drew out our triangle on the scale of 100 feet to the inch we found that the shorter side directly in front of the tent was almost exactly 13 inches long.  This meant that the river at this point was 1,300 feet wide, nearly a quarter of a mile.  On the other side of the island we found, in the same way, that the river at its narrowest point was about 500 feet wide.  This portion of the river we named Lake Placid, as the water was very still and quite deep.  This was due to a sort of natural dam formed at the lower end of our island.  The small island that Dutchy found was kite-shaped, with a tail of boulders which extended almost all the way across to a rocky point on the Pennsylvania shore.  The channel between “Kite Island,” as we called it, and Willow Clump Island was not more than fifteen feet wide in some places, and through this the water swept with a swift current down past a narrow neck of land to join the main current.  This narrow stretch of land we named the Tiger’s Tail, owing to its peculiar shape.  It was in the hook at the end of this tail that we discovered the old bridge wreck above referred to.  From the tip of the Tiger’s Tail to Point Lookout, at the extreme upper end of Willow Clump Island, it was a little under a half-mile.  The shore all along Lake Placid was very steep, except near Point Lookout.  At one place there was a shallow bay which we called the lagoon.

CHAPTER VIII.

SWIMMING.

[Illustration:  Fig. 85.  The Diving Tree.]

Lake Placid was a favorite swimming place for us.  We used to plunge in from the branches of a tree which overhung the water a little ways above the lagoon and made a natural springboard.  We could all swim like ducks, except Dutchy, who couldn’t do anything but paddle.  However, Uncle Ed was an expert, and he took Dutchy in hand and soon made a pretty good swimmer out of him.  He also taught us some fancy strokes.  Of course I took no record of these lessons.  You would hardly expect me to sit on the bank with a book in hand jotting down notes while the rest were splashing around in the cool water having the best of fun in the world, and even if I had, I wouldn’t republish the notes here, because whoever heard of a boy learning to swim while reading a book on the subject?  A beginner had better leave books alone and plunge right into the water.  He will