collected by skilled field inspectors in the neighborhood of the larger
commercial and building centers; similar field sampling of building
stones and of clays and clay products, offered for use in Government
buildings or engineering construction; and the forwarding of such
samples to the testing laboratories at St. Louis or Pittsburg for
investigation and test. The investigative tests include experiments
regarding destructive agencies, such as electrolysis, alkaline earths
and waters, salt water, fire, and weathering; also experiments with
protective and water-proofing agencies, including the various washes or
patented mixtures on the market, and the methods of washing, and mixing
mortars and concrete, which are likely to result in rendering such
materials less pervious to water.

Investigations are also being conducted to determine the nature and
extent of materials available for use in the building-construction work
of the Government, and how these materials may be used most efficiently
and safely. While the act authorizing this work does not permit
investigations or tests for private parties, it is believed that these
tests for the Government cannot fail to be of great general value. The
aggregate expenditure by the Federal Government in building and
engineering construction is about $40,000,000 annually. This work is
being executed under so many different conditions, at points so widely
separated geographically, and requires so great a variety of materials,
that the problems to be solved for the Government can hardly fail to
cover a large share of the needs of the Engineering Profession, State
and municipal governments, and the general public.

_Character of the Work._--The tests and analyses, of the materials of
construction purchased by the various bureaus and departments for the
use of the Government, are to determine the character, quality,