Cork insulation; a complete illustrated textbook on cork insulation ...

STANDARD CAR 455
was obvious, too, that no amount of work to teach better field,
orchard and packing house methods would have the desired result
namely, freedom from decay at the market— until the construction
of the refrigerator cars was suited to the work which they were expected
to perform. To determine in detail what that construction
must be, opened a new phase of the problem.
In the first place the thermograph was relegated to the garret.
It was no longer sufficiently exact for our purposes nor could its
information be made sufficiently specific. We substituted the resis-
tance thermometer, so constructed that it might be plunged into the
orange, chicken or fish, as well as hung in the air of the car or placed
firmly against the car body. These thermometers were sensitive to
a tenth of a degree Fahrenheit. They were attached to long wires
which were passed between the packing of the door and the jamb
without admitting air and were collected into cables with terminals
on top of the car, or which extended from car to car and so into a
caboose, or living car, where all the thermometers in the cars under
observation might be read by plugging into a switch board attached
to an indicator. In this manner the environment of all cars was
kept the same and, if the variables in each car were reduced to one,
a direct comparison of the temperatures observed furnished valuable
information.
The number of cars under observation in the same train, loaded
with the same commodity, has varied from two to fourteen. The
hauls have been from one hundred to three thousand miles, during
which the cars were not opened. Readings of the thermometers were
made, on the average, once every four hours. The ice and salt
which went into the bunkers were weighed by the investigators and
in some experiments the water issuing was measured. When salt
was used with the ice, the specific gravity of the issuing brine was
taken at frequent intervals.
Gradually a uniform plan was developed for the placing of the
thermometers in the commodity and in the car, as key positions were
located. Ordinarily twelve thermometers are used in each car, dis-
tributed as follows:
( 1) On the floor, midway between the doors, middle of car.
( 2) On the ceiling midway between the doors, middle of car.
( 3) On the wall, quarter way of car, door height.
( 4) In air, bottom bulkhead opening, midway between walls.
( 5) In air, floor, midway between doors, middle of car.
( 6) In air, ceiling, midway between doors, middle of car.
( 7) In package, bottom layer, first stack, middle row.
( 8) In package, top layer, quarter way stack, wall row.
( 9) In package, bottom layer, middle stack, middle row.
(10) In package, top layer, middle stack, middle row.
(11) In package, quarter way stack, middle layer, middle row.
(12) In package, top layer, first stack, middle row,
—