of time measure and the units of angular measure
in the sexagesimal system are as follows:
Temperature Measurement
In certain types of measurement, when the
existing temperature differs from a standard
temperature, the measured values will be in
error and must be corrected, In each of the several
temperature-measurement scales, the unit of
measure is called a DEGREE, which varies for
the different temperature scales, When the
scale extends below zero, values below zero are
identified by a minus sign. Temperatures are writ-
ten, for example, as 23°F or – 5°C, the letter
designating the particular temperature scale. To
avoid confusion when writing or talking about
temperature, we should always be sure to indicate
the type of scale used, Two of the most commonly
used temperature scales are the CENTIGRADE
scale and the FAHRENHEIT scale.
On the Centigrade scale (also known inter-
nationally as “Celsius Scale” after Anders
Celsius, a Swedish astronomer who first devised
it), zero is the freezing point of water, and plus
100 is its boiling point.
On the Fahrenheit scale, the temperature of
the freezing point of water is plus 32°, and its
boiling point is plus 212°.
Now let us compare these scales. A Fahrenheit
degree represents five-ninths of the change in heat
intensity indicated by a degree on the Centigrade
scale. Temperatures on either of the two scales
can be converted to the other by the following
formulas:
Degrees C = 5/9 (degrees F – 32°,
Degrees F = (9/5 degrees C) + 32°
Note that, when converting Fahrenheit to
Centigrade, you should first subtract the 32°, then
multiply by 5/9. When converting Centigrade to
Fahrenheit, you should first multiply by 9/5, then
add the 32°.
Pressure Measurement
Measurements of atmospheric pressure are
used in surveying to determine approximate
differences in elevation between points on the
earth’s surface and to determine the best
approximate correction for the effect of atmos-
pheric refraction. The units of measure for
atmospheric pressure and their relationships are
as follows:
1 atmosphere = 29.9212 inches of mercury
= 760 millimeters of mercury
= 14.6960 pounds per square inch
= 1,03323 kilograms per square
centimeter
= 33.899 feet of water
= 1.01325 bars, or 1013.25
millibars
Dry Measure
Dry measure is a system of measure of volume
used in the United States for dry commodities,
such as grains, fruits, and certain vegetables. The
basic unit in dry measure is the BUSHEL. The
standard U.S. bushel contains about 77.6 lb of
water. Since there are about 62.4 lb of water in
a cu ft, it follows that a U.S. bushel has a volume
of
Units of dry measure are as follows:
1 bushel = 4 pecks
1 peck = 8 quarts
1 quart = 2 pints
Board Measure
Board measure is a method of measuring
lumber in which the basic unit is a BOARD FOOT
(bf). A board foot is an abstract volume 1 ft long
by 1 ft wide by 1 inch thick. The chief practical
use of board measure is in cost calculations;
lumber is sold by the board foot just as sugar is
sold by the pound.
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