(1d)-
In spite of all these advantages, however, the Wright brothers
might not have succeeded had they not been born at precisely
the right moment in history. Attempts to achieve manned flight
in the early nineteenth century were doomed because the
steam engines that powered the aircraft were too heavy in 35
proportion to the power that they produced. But by the end of
the nineteenth century, ( 4 4 ) the brothers were experimenting
with engineering options, a relatively light gasoline engine had
already been invented, and they were able to bring the ratio of
weight to power within acceptable limits for flight.
40
