e that of a
river. It comes as a rolling mass, full of tumultuous whirls and eddies,
like those issuing from a chimney; and they strike the apparatus with
constantly varying force and direction, sometimes withdrawing support
when most needed. It has long been known, through instrumental
observations, that the wind is constantly changing in force and
direction; but it needed the experience of an operator afloat on a
gliding machine to realise that this all proceeded from cyclonic action;
so that more was learned in this respect in a week than had previously
been acquired by several years of experiments with models. There was a
pair of eagles, living in the top of a dead tree about two miles from
our tent, that came almost daily to show us how such wind effects are
overcome and utilised. The birds swept in circles overhead on
pulseless wings, and rose high up in the air. Occasionally there was
a side-rocking motion, as of a ship rolling at sea, and then the birds
rocked back to an even keel; but although we thought the action was
clearly automatic, and were willing to learn, our teachers were too
far off to show us just how it was done, and we had to experiment for
ourselves.'

Chanute provided his multiple glider with a seat, but, since each
glide only occupied between eight and twelve seconds, there was little
possibility of the operator seating himself. With the multiple glider a
pair of horizontal bars provided rest for the arms, and beyond these
was a pair of vertical bars which the operator grasped with his hands;
beyond this, the operator was in no way attached to the machine. He
took, at the most, four running steps into the wind, which launched
him in the air, and thereupon he sailed into the wind on a generally
descending course. In the matter of descent Chanute observed the sparrow
and decided to imitate it. 'When the latter,' he says, 'approaches the
street, he throws his body back, tilts his outspread wings nearly square
to the course, and on the cushion of air thus encountered he stops his
speed and drops lightly to the ground. So do all birds. We tried it with
misgivings, but found it perfectly effective. The soft sand was a great
advantage, and even when the experts were racing there was not a single
sprained ankle.'

With the multiple winged glider some two to three hundred glides were
made without any accident either to the man or to the machine, and the
action was found so effective, the principle so