ath of free air.

In another chapter I have told you how Roger Bacon, the great genius of
the thirteenth century, was prevented for years from writing a single
word, lest he get into new troubles with the authorities of the church.
And five hundred years later, the contributors to the great philosophic
"Encyclopaedia" were under the constant supervision of the French
gendarmerie. Half a century afterwards, Darwin, who dared to question
the story of the creation of man, as revealed in the Bible, was
denounced from every pulpit as an enemy of the human race.

Even to-day, the persecution of those who venture into the unknown realm
of science has not entirely come to an end. And while I am writing this
Mr. Bryan is addressing a vast multitude on the "Menace of Darwinism,"
warning his hearers against the errors of the great English naturalist.

All this, however, is a mere detail. The work that has to be done
invariably gets done, and the ultimate profit of the discoveries and the
inventions goes to the mass of those same people who have always decried
the man of vision as an unpractical idealist.

The seventeenth century had still preferred to investigate the far off
heavens and to study the position of our planet in relation to the solar
system. Even so, the Church had disapproved of this unseemly curiosity,
and Copernicus who first of all had proved that the sun was the centre
of the universe, did not publish his work until the day of his death.
Galileo spent the greater part of his life under the supervision of the
clerical authorities, but he continued to use his telescope and provided
Isaac Newton with a mass of practical observations, which greatly helped
the English mathematician when he dis-covered the existence of that
interesting habit of falling objects which came to be known as the Law
of Gravitation.

That, for the moment at least, exhausted the interest in the Heavens,
and man began to study the earth. The invention of a workable
microscope, (a strange and clumsy little thing,) by Anthony van
Leeuwenhoek during the last half of the 17th century, gave man a chance
to study the "microscopic" creatures who are responsible for so many of
his ailments. It laid the foundations of the science of "bacteriology"
which in the last forty years has delivered the world from a great
number of diseases by discovering the tiny organisms which cause the
complaint. It also allowed the geologists to make a more careful stud