-horse-power aeroplane
being therefore able to fly four days with a battery weight of but four
hundred pounds.

"Limestone and clarified acid are the principal parts of these
batteries. It was known long ago that there was about as much
imprisoned solar energy in limestone as in coal, but it was only
recently that we discovered this way of releasing and using it.

"Common salt plays an important part in many of our chemical reactions.
By combining it with limestone, and treating this with acid jelly, we
also get good results on raising to the boiling-point.

"However enjoyable the manly sport of yachting is on water, how vastly
more interesting and fascinating it is for a man to have a yacht in
which he can fly to Europe in one day, and with which the exploration
of tropical Africa or the regions about the poles is mere child's play,
while giving him so magnificent a bird's-eye view! Many seemingly
insoluble problems are solved by the advent of these birds. Having as
their halo the enforcement of peace, they have in truth taken us a long
step towards heaven, and to the co-operation and higher civilization
that followed we shall owe much of the success of the great experiment
on Mother Earth now about to be tried.

"Another change that came in with a rush upon the discovery of a
battery with insignificant weight, compact form, and great capacity,
was the substitution of electricity for animal power for the movement
of all vehicles. This, of necessity brought in good roads, the results
obtainable on such being so much greater than on bad ones that a
universal demand for them arose. This was in a sense cumulative, since
the better the streets and roads became, the greater the inducement to
have an electric carriage. The work of opening up the country far and
near, by straightening and improving existing roads, and laying out new
ones that combine the solidity of the Appian Way with the smoothness of
modern asphalt, was largely done by convicts, working under the
direction of State and Government engineers. Every State contained a
horde of these unprofitable boarders, who, as they formerly worked,
interfered with honest labour, and when idle got into trouble. City
streets had been paved by the municipality; country roads attended to
by the farmers, usually very unscientifically. Here was a field in
which convict labour would not compete, and an important work could be
done. When once this was made the law, eve