ithin a few yards of land. Even then, it must have been
twenty feet at least, the bottom sloping as abruptly from the shore as
the roof of a house. Consequently the approach was safe and easy.

In such favorable conditions there was no difficulty in laying the launch
near the bank, where, as in former instances, she was made fast by the
bow line looped around a sturdy spruce more than six inches in diameter,
and the anchor out over the stern. Chester tied the knot securely, and
stepped back to give what help he could to Alvin, who was busy with the
engine. Mike looked on and remarked that, although he knew nothing at all
about the various contraptions, he held himself ready to give valuable
advice whenever it was needed.

"Being as mesilf ain't indispinsable just now, 'spose I strolls up to the
city nixt door and make a few more new acquaintances."

"There is no objection to that," replied the Captain, "but be sure to
come back before dark."

Mike sprang lightly to land and set off on his journey of discovery. It
will be recalled that our friends were some distance from the highway
connecting the wharf and town and therefore he had to thread his way
among the trees to reach the direct route to the village. There was no
trouble in doing this: the trouble came afterward.

Alvin and Chester gave the lad no thought, for he surely was old enough
to take care of himself, and there was nothing in the situation to cause
any misgiving. Their ambition was to get the engine of the launch in
shape. With painstaking care and the expenditure of more time than was
expected, Alvin finally discovered that the heat of the exhaust pipe was
due to the clogging of the pump with weeds, and not to the lack of
lubrication or the retarding of the spark.

To the disgust of both, when a test was made with the launch still held
immovable, and the heating was overcome, explosions in the muffler
developed.

"Now we must find whether that is caused by a cylinder missing fire and
pumping the gas into the muffler."

"How will that do it?" asked Chester, who, while a good motor boat pilot,
possessed less practical knowledge than his chum.

"The charges which I spoke of are ignited from the heat of the next
exhausted charge. It may be the exhaust valve is stuck or does not seat
properly, or the gas mixture is too weak to fire in the cylinder, or the
spark may be insufficient or over-retarded. It is a job to get that
straightened out, and when t