In entering the steam department, where he is to be employed, the eye
of the beginner is greeted with the sight of coal, water, oil, etc.,
and he is told of invisible materials, such as air, steam and gases; it
is the proper manipulation of these seen and unseen material products
as well as the machines, that is to become his life task. In aiding
to the proper accomplishment of the yet untried problems nothing can
be more useful than to know something of the nature and history of
the different forms of matter entering into the business of steam
production. Let us begin with