trades. In six years he has made a complete study of eight of the most
important trades--excavation, masonry (including sewer-work and paving),
carpentry, concrete and cement work, lathing and plastering, slating and
roofing and rock quarrying. He took every stop watch observation himself
and then, with the aid of two comparatively cheap assistants, worked up
and tabulated all of his data ready for the printer. The magnitude of
this undertaking will be appreciated when it is understood that the
tables and descriptive matter for one of these trades alone take up
about 250 pages. Mr. Thompson and the writer are both engineers, but
neither of us was especially familiar with the above trades, and this
work could not have been accomplished in a lifetime without the study of
elementary units with a stop watch.

In the course of this work, Mr. Thompson has developed what are in many
respects the best implements in use, and with his permission some of
them will be described. The blank form or note sheet used by Mr.
Thompson, shown in Fig. 2 (see page 151), contains essentially:
[Transcriber's note -- Figure 2 omitted]

(1) Space for the description of the work and notes in regard to it.

(2) A place for recording the total time of complete operations--that
is, the gross time including all necessary delays, for doing a whole job
or large portions of it.

(3) Lines for setting down the "detail operations, or units" into which
any piece of work may be divided, followed by columns for entering the
averages obtained from the observations.

(4) Squares for recording the readings of the stop watch when observing