ece from another these lines are
drawn at varying angles and of varying widths apart. In Figure 87 is
given a view of three cylindrical pieces. It may be known to be a
sectional view by the cross-hatching or section lines. It would be a
difficult matter to represent the three pieces put together without
showing them in section, because, in an outline view, the collars and
recesses would not appear. Each piece could of course be drawn
separately, but this would not show how they were placed when put
together. They could be shown in one view if they were shaded by lines
and a piece shown broken out where the collars and, recesses are, but
line shading is too tedious for detail drawings, beside involving too
much labor in their production.

[Illustration: Fig. 87.]

Figure 88 represents a case in which there are three cylindrical pieces
one within the other, the two inner ones being fastened together by a
screw which is shown dotted in in the end view, and whose position along
the pieces is shown in the side view. The edges of the fracture in the
outer piece are in this case cross-hatched, to show the line of
fracture.

[Illustration: Fig. 88.]

[Illustration: Fig. 89.]

In cross-hatching it is better that the diagonal lines do not quite meet
the edges of the piece, than that they should in the least overrun, as
is shown in Figure 89, where in the top half the diagonals slightly
overrun, while in the lower half they do not quite meet the outlines of
the piece.

In Figure 90 are shown in section a number of pieces one within the
other, the central bore being filled with short plugs. All the
cross-hatching was done with the triangle of 60 degrees and that of 90
degrees. It is here shown that with these two triangles only, and a
judicious arrangement of the diagonals, an almost infinite number of
pieces may be shown in cross section without any liability of mistaking
one for the other, or any doubt as to the form and arrangement of the
pieces; for, beside the difference in spacing in the cross-hatching,
there are no two adjoining pieces with the diagonals running in the same
direction. It will be seen that the narrow pieces are most clearly
defined by a close spacing of the cross-hatching.

[Illustration: Fig. 90.]

In Figure 91 are shown three pieces put together and having slots or
keyways through them. The outer shell is shown to be in one piece from
end to end, because the cross-hatching is not only equally spa