the back.

The introduction of the blue printing process has quite revolutionized
the drawing office, so far at least as we are concerned. Our drawings
are studies, left in pencil. When we can find nothing more to alter,
tracings are made on cloth. These become our originals, and are kept
in a fire-proof vault. This system is found admirably adapted to the
plan of making a separate drawing for each piece. The whole combined
drawing is not generally traced, but the separate pieces are picked
out from it. All our working copies are blue prints.

Each drawer contains fifty tracings. They are two and a half inches
deep, which is enough to hold several times as many, but this number
is quite all that it is convenient to keep together. We would
recommend for these shallower drawers.

Each drawing is marked in stencil in the lower right hand corner, and
also with inverted plates in the upper left hand corner, with the
letter and number of the drawer, and its own number in the drawer, as,
for example, 3F--31; so that whichever way the sheet is put in the
drawer, this appears at the front right hand corner. The drawings in
each drawer are numbered separately, fifty being thus the highest
number used.

For reference we depend on our indices. Each tracing, when completed,
is entered under its letter in the numerical index, and is given the
next consecutive number, and laid in its place.

From this index the title and the number are copied into other
indices, under as many different headings as possible.

Thus all the drawings of any engine, or tool, or machine whatever,
become assembled by their titles under the heading of such particular
engine, or tool, or machine. So also the drawings of any particular
part, of all sizes and styles, become assembled by their titles under
the name of such piece. However numerous the drawings, and however
great the variety of their subjects, the location of any one is, by
this means, found as readily as a word in a dictionary. The stencil
marks copy, of course, on the blue prints, and these when not in use
are kept in the same manner as the tracings, except that only
twenty-five are placed in one drawer.

We employ printed classified lists of the separate pieces constituting
every steam engine, the manufacture of which is the sole business of
these works, and on these, against the name of every piece, is given
the drawer and number of the drawing on which it is represented. The
office c