steam-cylinders, which is still in use.
Second, the casting of a steam-jacket in one cylinder, instead of being
made in separate segments bolted together with caulked joints, as was
previously done. Third, the new double-D slide-valve, by which the
construction and working of the steam-engine was simplified, and the
loss of steam saved, as well as the cylindrical valve for the same
purpose. And fourth, improved rotary engines. One of the latter was
set to drive the machines in his private workshop, and continued in
nearly constant work and in perfect use for about thirty years.

In 1801, Murdock sent his two sons William and John to the Ayr Academy,
for the benefit of Scotch education. In the summer-time they spent
their vacation at Bellow Mill, which their grandfather still continued
to occupy. They fished in the river, and "caught a good many trout."
The boys corresponded regularly with their father at Birmingham. In
1804, they seem to have been in a state of great excitement about the
expected landing of the French in Scotland. The volunteers of Ayr
amounted to 300 men, the cavalry to 150, and the riflemen to 50. "The
riflemen," says John, "go to the seashore every Saturday to shoot at a
target. They stand at 70 paces distant, and out of 100 shots they
often put in 60 bullets!" William says, "Great preparations are still
making for the reception of the French. Several thousand of pikes are
carried through the town every week; and all the volunteers and
riflemen have received orders to march at a moment's warning." The
alarm, however, passed away. At the end of 1804, the two boys received
prizes; William got one in arithmetic and another in the Rector's
composition class; and John also obtained two, one in the mathematical
class, and the other in French.

To return to the application of gas for lighting purposes. In 1801, a
plan was proposed by a M. Le Blond for lighting a part of the streets
of Paris with gas. Murdock actively resumed his experiments; and on
the occasion of the Peace of Amiens in March, 1802, he made the first
public exhibition of his invention. The whole of the works at Soho
were brilliantly illuminated with gas.

The sight was received with immense enthusiasm. There could now be no
doubt as to the enormous advantages of this method of producing
artificial light, compared with that from oil or tallow. In the
following year the manufacture of gas-making apparatus was added to the