Oxford Democrat. [volume] (Paris, Me.) 1833-1933, 1908-06-23

HOW THEY GET NATURAL ICE WITH
OUT FROST IN INDIA.

the year-November to Harch-when
the nights, although never reaching
even to freshness, can be made to pro-
duce many tons of Ice In the open.
The fields In which the ice Ii made are
low, fiat and open, and the Ice is pro-
duced In large lots when the tempera-
ture of the air IL Is degrees or 20 de-
grees F. above the congealing point,
writes L. Lodian In the Scientific Ameri-
can. The method practiced is an in
structive example of keen observation
adapted to material purposes by nation
which Is to-day ignorant Of the science
of the thing-that is, they could not ex-
plain II questioned what actually causes
the forming of the ice beyond few
vague phrases, like "the wind" and
"keeping the earthly heat down." Yet
this same ice forming process has been
utilized in India since the ages that are
"lost in the night of time," and all with
q scientific observation and accuracy
which the Hindoo has acquired by In
stinct handed down through countless
generations.
The ice plot is rectangular piece of
ground, say, $50 feet long by 80 broad,
running in an easterly and westerly d.
rection. The soil is removed to depth
of q couple of feet. This excavation
when made is smoothed and then allow
ed to remain exposed to the torrid rays
of the sun to dry; then rice straw in
small sheaves is laid in an oblique d.
rection in the hollow, with loose straw
on the top to the depth of foot and a
half, leaving Its surface half foot be-
low that of the ground.
Numerous beds of this kind are form
ed-the ensemble constituting the ice
farms-with narrow sidewalks between
them, in which here and there large
covered earthen water jugs are sunk in
the ground for the convenience of having
water near by to fill the shallow earthen
vessels in which it is to be frozen. These
dishes are nine inches in diameter at the
top, diminishing to five inches at the
bottom, one and one-half inches deep
and one-quarter inch thick, and are so
porous as to soon become moist through
out when water is placed In them.
When evening comes the shallow
earthenware pans are placed in rows
upon the litter, and by means of little
burned tilt pots secured to the ends OF
lengthy bambusa canes each pan is half
filled with water. The quantity never
theless varies according to the ex-
pectation of ice. The natives can fore
cast that by the aspect of the heavens
and the evenness with which the air
currents come from the northwest.
There are abont 6, 900 plates in each OF
the beds, and the ice yield will average
quarter pound from each dish.
In the cool season when the tempera-
ture of the air at the ice fields Is under
so degrees F. and there are gentle breezes
from the north and west directions ice
appears in a night in all of the shallow
pans. Native watchers are on the look
out to note when a thin film appears on
the water in the pans, when the contents
of several are mixed together and
sprinkled over the other dishes. This
method augments the freezing action.
Stagnation has been discovered by the
natives to diminish the quantity of ice
produced. When the armament is en-
tirely clear, with zephyr currents from
the northwest, the congelation begins
before or about midnight and continues
to advance till morning, when the thick
est ice is formed. 1t is often an inch
thick, and sometimes the whole contents
of the dish are frozen compact.
The ice dishes present large moist
external surface to the air currents, pro-
iducing rapid evaporation and lowering
of the temperature. The water which
percolates through the porous trays ex-
poses so large a surface to the breeze
that it is promptly frozen. In addition
to the evaporative effect we also have
the influence of heat insulation to fall
back upon in explaining the phenome-
non.
The thick layer of dry straw In the ice
beds forms a large surface which Is
poor conductor Of heat. The heat can
penetrate but a little way into it during
the day. So soon as the sun sets this
large and powerfully radiating surface is
brought into action and affects the water
in the thin, porous pans, themselves
strong radiators.
Some of the natural "ice farms" Of
Bengal produce in a single night over ten
tons of ice, employing 800 persons of all
sizes and ages, and the early morning
harvesting of the ice by these 1.-the
gentry darting about is one of the few
animated scenes worth noting In the
Ganges region.