materials, were examined, of which more than 300 failed to meet the
specified requirements, representing many thousands of dollars worth of
inferior material rejected, which otherwise would have been paid for by
the Government. These tests were the means of detecting the inferior
quality of large quantities of materials delivered on contracts, and the
moral effect on bidders has proven as important a factor in the
maintenance of a high quality of purchases, as in the saving of money.

The examination of sands, gravels, and crushed stones, as constituent
materials for concrete and reinforced concrete construction, has
developed data showing that certain materials, locally available near
large building centers and previously regarded as inferior in quality,
were, in fact, superior to other and more expensive materials which it
had been proposed to use.

These investigations have represented an actual saving in the cost of
construction on the work of the Isthmian Canal Commission, of the
Supervising Architect, and of certain States and cities which have
benefited by the information disseminated regarding these constituent
materials.

Investigations of clay products, only recently inaugurated, have already
resulted in the ascertainment of important facts relative to the colloid
matter of clay and its measurement, and the bearing thereof on the
plasticity and working values of various clays. The study of the
preliminary treatment of clays difficult to handle dry, has furnished
useful information regarding the drying of such clays, and concerning
the fire resistance of bricks made of soft, stiff, or dried clay of
various densities.