ch pile of lumber when first piled
in the yard, and later when sold it should be again tested and the two
records given to the purchaser.

=Factories.=--Should test and mark the lumber when first received, and
if piled in the yard to be kiln-dried later, it should be tested
before going into the dry kiln, and again before being removed, and
these records placed on file for future reference.

Kiln-dried lumber piled in storage rooms (without any heat) will
absorb 7 to 9 per cent of moisture, and even when so stored should be
tested for moisture before being manufactured into the finished
product.

Never work lumber through the factory that has more than 5 or 6 per
cent of moisture or less than 3 per cent.

Dry storage rooms should be provided with heating coils and properly
ventilated.

Oak or any other species of wood that shows 25 or 30 per cent of
moisture when going into the dry kiln, will take longer to dry than it
would if it contained 15 to 20 per cent, therefore the importance of
testing before putting into the kiln as well as when taking it out.

The Electric Heater

In Figure 101 is shown the Electric Heater. This heater is especially
designed to dry quickly the test pieces for use in connection with the
Scalometer (see Fig. 100) without charring them. It may be attached to
any electric light socket of 110 volts direct or alternating current.
A metal rack is provided to hold the test pieces vertically on edge.

[Illustration: Fig. 101. The Electric Heater.]

Turn the test pieces over once or twice while drying.

It will require from 20 minutes to one hour to remove all the moisture
from the test pieces when placed on this heater, depending on whether
they are cut from green, air-dried, or kiln-dried boards.

Test pieces cut from softwoods will dry quicker than those cut from
hardwoods.

When the test pieces fail to show any further loss in weight, they are
then free from all moisture content.

BIBLIOGRAPHY

AMERICAN BLOWER COMPANY, Detroit, Mich.

IMRE, JAMES E., "The Kiln-drying of Gum," The United States
Dept. of Agriculture, Division of Forestry.

NATIONAL DRY KILN COMPANY, Indianapolis, Ind.

PRICHARD, REUBEN P., "The Structure of the Common Woods,"
The United States Dept. of Agriculture, Division of Forestry,
Bulletin No. 3.

ROTH, FILIBERT, "Timber," The United States Dept. of Agriculture,
Division of Forestry, Bu