Evening star., 1952-07-02
Summer Heat Counted
By Hours in Survey
85oF. About One-Fifth of Time
Over One Third of Nation

85oF. About One-Fifth of Time
Over One-Third of Motion
By Thomas R. Henry
During a warm summer hourly
temperatures exceed 85' F. about one
fifth of the time over nearly q third
of the United States.
This Is the finding OF DR.. Arnold
Court. meteorologist of the Office of the
Quartermaster General, just reported in
the monthly review of the United States
Weather Bureau. It Is based on records
Of 102 observing stations scattered over
the country, over a period of five years.
as cited in various reports.
The records show. DR.. Court says.
that two-thirds of all hourly readings
during the summer are above this value
in Central Texas, Central California and
the lowland desert area of California,
Arizona, Nevada and Utah.
On the other hand, he reports, "less
than tenth of all summer hours have
temperatures above 85' along the
Oregon coast, around the
Great Lakes or in the Northeastern
States. There is very little likelihood
Of such temperatures in the northern
Rocky Mountains, the central APP
palachians and the mountains of
Northern New York and New England.
Occur Out Of Season.
Temperatures above 85' occur In
spring and autumn as well as in summer.
but over most of the United States
about four-fifths Of the hours with such
Temperatures fall in the three summer
months"
The figure of 85' F. was not selected
arbitrarily for the study DR.. Court says.
but because this is about the tempera-
ture at which human discomfort Is
first demonstrated by removal of coats
and turning on Of fans.
He presents the following table Of
the total hours during the three summer
months at which temperature above IS.
may be expected, relying on past ex-
perience. at different cities:
Salt Lake. 2.192: Syracuse, 754; Erie,
Pa, 278; Spokane. 1,103; Madison, Wis.
704; Omaha, 2,602: Detroit. 744; Kansas
City, 3,504; Ell Paso, 1924; Greensboro.
N. c., 1895; Atlanta. 2,188: Louisville.
1915; Medford. Oreg., 1,545: Memphis.
3.149; Nashville, 2.431; Fresno. $3.50:
Jacksonville. 2.838.
X
Radio navigation tables for 100 Of
the principally Travelled areas of the
world now are complete.
This progress towards making uni
versally practical the So-called Loran
{ navigation system has just been re-
ported by United States Bureau Of
Standards scientists after nearly 10
years work. 1t has been a gigantic
calculating job.
At first, desk calculating machines
were used. These required the concerted
efforts of 80 computers about 2.400 man
hours to complete a single table. Later
the calculations were made with elec-
tronic calculators capable of multiplying
and dividing two 10-digit numbers at
the rate of 5000 an hour. Three per-
sons using this equipment could COM
plete a single table in $50 man-hours
and 240 machine -hours. Now. with the
use Of one Of the bureaus new calcu-
lating machines, it is possible to compute
one Of the tables in about 20 hours.
AS soon as it is completed a table is
published by the Navy photographic
Office and distributed to the armed serv-
ices.
Loran has proved to be one of the
most reliable means for navigating far
out at sea or in the air. Transmission
Of the low-frequency radio waves used
is effective up to distances of 700 nauti-
cal miles during the day and 1,400 at
night.
Must Be Free Of Error.
Without precise tables, however, the
navigator Is greatly handicapped. Navi-
CATION involves a determination of posi-
ton with information derived from the
time intervals between two or more pairs
OF transmitting stations. In practice a
three-Station network is used-a master
and two "Slave" tranSmitters. The low
frequency signals are transmitted as
series Of timed pulses. The pulses from
the Slaves" are spaced within the in
tervals between those from the master.
At increasing distances from the i'm
mediate transmitter area the time in
tervalS between the slave and master
pulses will vary, depending on the rel
ative positions Of the vessel and the
pair Of stations.
Special receivers aboard the ship or
aircraft are designed so that the time
difference can be read directly. The
bureaus tables for this particular fre-
quency. pair of stations and time of day
will yield one line of position for the
vessel. The receiver then is switched over
to the other pair of stations-the master
and the second "slave"-and another
time difference is shown. BY triangula-
ton on chart with these two lines the
absolute position Of the craft is deter
mined.
The tables. however, must be abso-
lutely free Of error. A very slight dis
crepancy could result in dangerously
incorrect position.
Questions and Answers
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any any question Of fact BY either writing The
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