volumes of the International Library of Technology are made up
of Instruction Papers, or Sections, comprising the various
courses of instruction for students of the International
Correspondence Schools. The original manuscript for each
Instruction Paper is prepared by a person thoroughly qualified,
both technically and by experience, to write with authority on
his subject. In many cases the writer is regularly employed
elsewhere in practical work and writes for us during spare time.
The manuscripts are then carefully edited to make them suitable
The only qualification for enrolment as a
student in these Schools is the ability to read English and to
write intelligibly the answers to the Examination Questions.
Hence, our students are of all grades of education, and our
Instruction Papers are, therefore, written in the simplest
possible language so as to make them readily understood by all
students. If technical expressions are essential to a thorough
understanding of the subject, they are clearly explained when
The great majority of our students wish to
prepare themselves for advancement in their vocations or to
qualify for other and more congenial occupations. Their time for
study is usually after the day's work is done and is limited to
a few hours each day. Therefore, every effort is made to give
them practical and accurate information in clear, concise form,
and to make this information include all of the essentials but
none of the non-essentials.
To effect this result derivations of rules and
formulas are usually omitted, but thorough and complete
instructions are given regarding how, when, and what conditions
any particular rule, formula, or process can be applied.
Whenever possible one or more examples, such as would be likely
to arise in actual practice, together with their solutions, are
given for illustration.
As the best way to make a statement,
explanation, or description clear is to give a picture or a
diagram in connection with it, illustrations are very freely
used. These illustrations are especially made by our own
Illustrating Department in order to adapt them fully to the
requirements of the text.
Projection drawings, sectional drawings, outline
drawings, perspective drawings, partly shaded or full shaded,
are employed, according to which will best produce the desired
result. Halftone engravings are used only in those cases where
the general effect is desired rather than the actual details.
In the table of contents that immediately
follows are given the titles of the Sections included in this
volume, and under each title is listed the main topics
discussed. At the end of the volume will be found a complete
index, so that quick reference can be made to any subject
International Textbook Company