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EGGS IN COLD STORAGE

THEORY AND PRACTICE IN PRESERVING EGGS BY RE-
FRIGERATION. DATA, EXPERIMENTS, HINTS ON
, CONSTRUCTION, ETC., FROM PRACTICAL
EXPERIENCE, WITH ILLUSTRATIONS.

MADISON COOPER.

CHICAGO :
H. S. RICH & CO.

1899.

«£

Copyrighted 1898, IX1)')
BY MADISON COOPER.

PKKSS OK

ICK AND RKFRIOIOK \ riox.

CHICAGO.

PREFACE.

IN the interest of a better understanding1 and dissem-
ination of knowledge on the cold storage of eggs,
the writer has communicated with quite a large num-
ber of individuals and companies, asking their ideas
and requesting that they give full answers to a printed
list of questions sent them. Although, at first, the
replies were rather slow in coming in, the total result
of these letters has been most gratifying; nearly one-
half acknowledging receipt of the inquiry, and more
than one-half of this number giving fairly full replies
to the questions submitted. Considering the fact
that the inquiries were regarded by some as being of
a rather personal nature, the proportion of managers
sending full replies is large. Several gentlemen were
frank enough to say that personal considerations pre-
vented them from giving any information; others
gave guarded or partial replies. In the main, how-
ever, storage men have been willing to give informa-
tion and exchange ideas.

The list of inquiries sent out covers the subject
very thoroughly, and divides it into six different
parts, with three separate questions relating to each.
To the data so cheerfully furnished by others is added
information from thewriter's experience and practice,
with such explanation of theory and practice as may
seem necessary to a clear understanding of the prin-
ciples of successful egg refrigeration. It is hoped
that those who are new to the business may obtain
valuable information from these collected data, and
that those with experience may derive some benefit
in the way of a review, and possibly pick up some
new ideas as well.

A large portion of the matter contained in these

Q C U fi x -

4 PREFACE.

pages appeared in Ice and Refrigeration as a series
of articles entitled: "Eggs in Cold Storage." The
present book is printed for the purpose of putting
the matter in permanent form, believing that those
who have followed the original articles would find it
convenient for future reference. While the present
book has many shortcomings, and there is no doubt
room for the addition of much information, reliable
data, and the results of extended observations and
tests, there has not heretofore been anything like a
complete write-up of the subject; and in consideration
of this fact the reader is asked to be liberal in his
criticism.

If any errors or lack of details are noted, the
author would gladly acknowledge and explain the
points at fault if his attention is called toany. No other
object has been in mind in writing these articles than
a furtherance of scientific knowledge on the subject
of refrigeration as applied to the preservation of per-
ishable products, and the great assistance rendered
by those who have written painstaking replies to the
list of inquiries is hereby acknowledged. The com-
bination and comparison of information are beneficial,
and if those who have further data or records of tests
will only put them before others in their line of busi-
ness, no loss will be sustained by the individual giv-
ing the information, while much general good will
result.

INTRODUCTION.

THE value of the eggs placed in cold storage for
preservation is estimated at about $20,000,000
annually for the United States alone. Considering
the importance the industry has already attained, its
rapid growth and future outlook, the amount of ac-
curate information available to those engaged in the
business seems very meager. The difficulties to be
overcome, the skill required. and the importance of a
well designed structure are not usually explained by
those interested in promoting new enterprises in this
line, and consequently not appreciated by those mak-
ing the investment. Financial disaster has over-
taken many large companies who have erected costly
refrigeratingwarehouses; thosewhich have succeeded
have been forced to install new systems, make expens-
ive changes, and make a thorough study of the prod-
ucts handled. The experience of nearly all has been
emphasized at times by heavy losses paid in claims
made by customers for damage to goods while in
storage, or the necessity of running a large house
while doing a very small business. Those about to
become interested in the business may find food for
thought in the above, and the history of a dozen
houses, in diiferent localities, will be good information
for would-be investors.

The scarcity of knowledge on the subject in hand,
while being partly the result of the half developed
state of the art until very recently, is also very
largely owing to narrow-mindedness on the part of
some of the older members of the craft, who have
largely obtained their skill by years of experience
and study, some of them having expended large sums
on experimental work. The same experiments have

6 INTRODUCTION.

perhaps been made before, and are of necessity to
be made again by others, simply because the first
experimenter would not give other people the benefit
of his experience. It seems at this stage in the de-
velopment of refrigeration, that the improvements to
be made during- the next twenty years will be of very
much less importance than those made during- the
twenty years just ending-; trade secrets, so jeal-
ously guarded by some, must disappear, as they have
in other branches of engineering-. Storag-e men have
been oblig-ed to work out their own salvation in stor-
ing- problems, sometimes sending their most difficult
points to be answered through the columns of Ice and
Refrigeration, and, perhaps, comparing ideas with
those of their personal friends in the same line of
business. It is to be observed that the most pro-
gressive and up-to-date manufacturing concerns in
the United States to-day are giving their contempo-
raries every opportunity of observing their methods,
and are very willing and anxious to talk over matters
pertaining to their work, from an unselfish stand-
point. So, too, the successful cold storage of the
future will be sure to make " visitors welcome."

In anything which will appear in these articles, it
is not the writer's intention to convey the idea that
any mere theoretical knowledge, which can be ac-
quired by reading and study, or even by an exchange
of ideas in conversation, can take the place of practi-
cal observation in actual house management; but
there are applications of well known natural laws,
which are not generally understood by storage men,
and their progress is handicapped from lack of this
theoretical knowledge. The two following illustra-
tions, bearing on temperature and ventilation, are
among the common errors made in practice, yet easily
understood when studied and tested: Some storage
houses have formerly held their egg rooms at 33° F.,
fearing any nearer approach to the freezing point of

INTRODUCTION. 7

water (32° F.), thinking- the eggs would freeze. A
simple experiment would settle this point, giving the
exact freezing- temperature, as well as the effect of
any low temperature on the egg tissues. Again,
others have thought to ventilate by opening- doors
during- warm weather. It never happens that storag-e
rooms can be benefited by this treatment at any time
during- the summer months, and only occasionally
during* spring- and fall. The dew point of outside air
is rarely below 45° F. during- summer, and when
cooled to the temperature of an eg-g- room, moisture
will be deposited on the goods in storage, causing- a
vigorous -growth of mildew.

EGGS IN COLD STORAGE.

CHAPTER I.

TEMPERATURE.

TEMPERATURE is selected for first considera- Temperature
. . . ., ,, ,. . . more important

tion, as it is the primary elementoi reingeration, than any other

Jf -,.,. ^ A condition.

and more important than any other condition. Correct
temperature alone, however, will not produce success-
ful results, anymore than a g-ood air circulation, or cor-
rect ventilation, would give good results with a wrong-
temperature. This applies more especially to egg re-
frigeration, someproducts requiringonlyalowtemper-
ature for preservation. The common impression of
cold storage is what the name implies — simply a build-
ing in which the rooms may be cooled to a low degree
as compared with the outside air. Even those who
build, sell and erect refrigerating machinery and appa-
ratus often show either gross carelessness or ignor-
ance of the requirements of a house which will produce
successful results. After a careful examination of
some of the recently constructed houses, supposed to
be strictly modern and up to date, the writer gets the
impression that the architects regard temperature
as the only requisite for perfect work. Some of the unskiiifuiiy
rooms in these new houses are simply insulated and e^j? m?ms.
fitted with brine or ammonia pipes, the location of the
coils having no attention whatever, being placed, in
most cases, in convenient proximity to the pipe main,
and in one or two instances, the top pipe of the cooling-
coils was fully two feet from the ceiling. The ne-
cessity of providing for air circulation seemed not
worthy of consideration, to say nothing of the lack of
anything like an efficient ventilating system.

Questions regarding the correct temperature of Opinions
egg rooms have been asked repeatedly of storage correct'"*

, - • j.i « • ' i i temperature.

men who have been in the business long enough to be

10 EGGS IN COLD STORAGE.

looked to for advice, the same person, perhaps,
giving- a different answer, from time to time, as his
ideas changed. The query has also been asked and
answered through the columns of ICE AND REFRIG-
ERATION a number of times. At present, however,
there is no temperature on which a large majority of
persons can agree as being- rig-ht, and as giving- su-
perior results to any other. The claims made by the
advocates of different temperatures will be consid-
ered, to determine, if possible, what degree is giving
the best results in actual practice.

The three questions relating to temperature were
temperature. written to draw out opinion as to the right tempera-
ture, the lowest safe temperature, and what delete-
rious effect, if any, the egg sustained at low tempera-
tures, which did not actually congeal the egg meat.
The three temperature queries were:

First. — At what temperature do you hold your
rooms for long period egg storage?

Second- — What temperature do you regard as the
lowest limit at which eggs may be safely stored?

Third. — What effect have you noticed on eggs held
at a lower temperature?
Fig-ures All the replies received contained answers relative

received relat-

to temperature, and by a very small majority 32° F.
is the favorite temperature for long period egg
storage. Some few, 33° F. and 34° F., with a few
scattering ones up to 40° F.. Under the freezing
point, none recommended a temperature lower than
28° F., and for a very obvious reason, this being near
to the actual freezing temperature of the albumen of
a fresh egg. A very respectable minority say a tem-
perature ranging from 30° F. to 31° F. is giving them
prime results; and several recommend 30° F. straight,
and say they should go no lower. In recent years
there has been a decided tendency among storage
men to get the temperature down near the safety
limit, but many houses are so poorly equipped that

EGGS IN COLD STORAGE. 11

they are unable to maintain a uniform low tempera-
ture below 33° F., without danger of. freezing- eggs
where they are exposed to the flow of cold air from
coils. A house must be nicely equipped to maintain
low temperatures with safety. More houses would
use temperatures under 32° F., were they able to,
without danger to the eg-g-s. A very successful east-
ern house issued a pamphlet in 1892. At that time
they maintained a temperature of 32° F. to 34° F. in
their rooms. In sending- out this little book during
the winter of 1897-98 a postscript was added, as fol-
lows: " This pamphlet was published in 1892, when
our plant was started. Since that time all first-
class cold storag-e houses have lowered their temper-
atures materially." No better illustration than this
can be cited to show the tendency of the times.
These people now use a temperature of 30° F. for
eg-g-s.

Most of the replies received contained answers toRePliesto

query No. 2.

question No. 2, and the greater portion state this as
being- about 2° F. lower than that recommended for
long- period storag-e. It is presumed that these two
degrees are allowed as leeway, or margin of safety,
for temperature fluctuations. Some state that eg-g-s
cannot be safely held below 32° F., but give no reason
why, while two or three say a temperature of 27° F.
will do no harm to eg-g-s in cases. One reply states
that egg's held in cut straw at 25° F. for three months
showed no bad symptoms. It has never been made
clear how the package can be any protection against
temperature, when the temperature has been contin-
uously maintained for a length of time sufficient to
allow the heat to escape; and we know that eggs will
positively freeze at 25° F., as proven by experiments
mentioned in another paragraph.

The answers to question No. 3 were few in num- Replies to

. ., __... . , 1 query No. 3.

ber, but cover a wide range. The scarcity of data on
this point indicates that few have experimented with

12 EGGS IN COLD STORAGE.

eggs at temperatures ranging- from 25° F. to 30° F.
Some say: "Dark spot, denoting germ killed"; others,
"white gets thin"; others, "eggs will decay more
quickly"; or, "they wnl not 'stand up' as long when
removed from storage." It is also claimed that "yolk
is hardened or 'cooked' when temperature goes below
32° F." Some answers state a liability of freezing if
eggs are held in storage at a temperature below 32C F,
for any length of time.

As far as possible, we will dig out reasons for the
temp£atureBW c^aims made by advocates of both high and low tem-
peratures, both having equal consideration. Taking
29° F. or 30° F. and 38° F. or 40° F., as representing
the lowest and highest of general practice, we will see
what is claimed by each ; and also the faults of the
other fellow's way of doing it, as they see it. Those
who are holding their egg rooms at 40° F. say it is
economical, that the eggs keep well, that the consis-
tency of the egg meat is more nearly like that of a
fresh egg after being in storage six months, than if
held at a lower temperature. As against a low tem-
perature they say: A temperature of 30° F. is expen-
sive to maintain; the yolk of the egg becomes hard
and the white thin, after being in store for a long
hold; and that when the eggs are taken from storage
in warm weather it will require a longer time to get
through the sweat than if held in storage at a some-
what higher temperature, resulting in more harm to
the eggs. Some claim that the keeping qualities are
impaired by holding at a temperature as low as 30C F.,.
and others note a dark spot, or clot, which forms in
the vicinity of the germ, when eggs are held below
33° F. Against this formidable array of claims, the
low temperature men have some equally strong
ones, although fewer in number. They say: There
is very much less mildew, or must, at 30° F. than at
temperatures above 32° F.; the amount of shrinkage
or evaporation from the egg is less; an egg can be

EGGS IN COLD STORAGK. 13

held sweet and reasonably full at this temperature
from six to eight months. This last claim is a broad
one, and very few houses are turning- out eggs an-
swering to this description.

The following, relating to high temperatures, is
quoted from a letter written by one of the best posted Je
men in the business, who has spent much money and
time on experiments, and studied the question for
years. He says: "A temperature of 40° F. is very
good for three months' holding, but if they run over
that, it is more than likely the eggs will commence to
cover with a white film, which grows the longer they
stand, and finally makes a musty egg." This gen-
tleman advocates a temperature of 30° F. for long
period holding. It should be noted that the high
temperature men ignore entirely the effect of high
temperatures on the growth of this fungus, spoken of
above as a white film. The worst £hing about most
storage eggs is the taste caused by this growth,
(usually called mildew or mold), which results in what
is commonly called a musty egg. To enable us to
understand the validity of these claims made by the
30° F. people, it will be necessary for us to ascertain
the conditions which are favorable, and also the con-
ditions which are unfavorable for the propagation of
this growth of fungus, which has given storage men
so much trouble, ever since cold storage was first
used for the preservation of eggs.

Heat and moisture are the two conditions lead ing- Causes operat-

& ing- to produce

to its rank growth, and the opposite — dry ness and cold [JI8rrow1JJ1of s
— will retard or stop the growth entirely. In moist, in oM storage,
tropical countries many species of this parasite grow,
while in the cold, dry regions of the north its exist-
ence is limited to a single variety. The causes lead-
ing to a growth of the fungus on the outside of an egg
are not far to seek. It feeds on the moisture and
products of decomposition which are being constantly
given off by an egg, from the time it is first dropped

14 EGGS' IN COLD STORAGE.

until its disintegration, unless immersed in a liquid,
or otherwise sealed from contact with the air. This
evaporation not only takes moisture from the egg,
but carries with it the putrid elements from the egg
tissue, resulting- from a partial decomposition of the
outer surface of the eg-g- meat. Conditions of excess-
ive moisture and the presence of decaying- animal or
vegetable matter, tog-ether with a moderate degree of
heat, are essential to the formation of fungus of the
species which are found growing- on eg-g-s in cold
storage. As the heat and moisture are increased, the
growth of fungus will be proportionate. Furthermore,
we all understand that heat hastens decomposition,
and the partial decomposition of an egg results in a
growth of the fungus, as before explained, when con-
ditions of temperature and humidity are favorable. If
the temperature is low, this growth is slow; for in-
stance, if eggs are held at a temperature of 30° F. in
an atmosphere of given humidity, the growth of fungus
is less rapid than if held at any temperature higher,
with the same per cent of humidity. As our subject
merges into humidity here, the reader is referred to
what is said under this head in another chapter,
someexperi- Returning to the objections urged against low

™<Skngnpoint temperatures, we will see what damage is claimed
from the use of a temperature of 29° to 30° F. The
objections are: Liability of freezing; germ is killed;
white becomes thin; yolk is hardened, and eggs will
not keep as long when removed from storage. Some
interesting results are obtained from experiments
made by the writer. Half-rotten or "sour" eggs
freeze at temperatures just a trifle under 32° F.
Fresh eggs freeze at 26° to 27° F. In testing eggs
which had been held in storage for several months, it
was noted that the freezing point had been depressed
from 1° to 2° F. An egg which is leaky will freeze at
2° to 3° higher temperature than one which is sound,
probably owing to the evaporation resulting in a lower

EGGS IN COLD STORAGE. 15

temperature. The freezing point of eggs, as above,
is understood as being the degree at which they begin
to form ice crystals inside. Of the replies received
touching on the freezing point of eggs, nearly all agree
with above experiments. The " dead germ " theory Dead germ
the writer has never been able to locate in fact, hav-
ing never seen anything of the kind in eggs held as
low as 28° to 29° F. for several weeks' time; nor in
eggs held at 30° F., or a trifle under, through the sea-
son. As only two or three mention having noted this
result, it would seem that some local conditions, and
not low temperature, were responsible.

The matter of the white becoming thin when eggs
are held at low temperatures has some bearing; in
fact, any egg held at a cold storage temperature for
a long carry will show this fault, to a certain extent,
especially if cooled quickly when stored, or warmed
suddenly when removed from storage. With refer-
ence to the above, it is the writer's opinion that a dif-
ference of 4° to 6° F. in carrying temperature will
not be noticeable in its effect on the albumen of an
egg; and as to the effect of a low temperature
on the egg yolk, it has been demonstrated that
any temperature, which will not actually congeal the
albumen, will not harm the yolk of an egg. There
is a slight tendency, in this case, to a similar effect to
that produced by a low temperature on cheese; that
is, causes it to become " short " or crumbly.

In regard to a low temperature egg not keeping as
long when removed from storage, it has been the
experience of the writer that no difference was noted
between eggs put out from storage and the current
receipts of fresh eggs, so far as any complaint or
objection was concerned, the eggs being shipped in
all directions, in all weathers and subject to many
different conditions. A test was also made, by placing A test showing

,, .. r i'iii, .... keeping- quali-

three dozen of eggs, which had been carried m storage ties of eggs

at a temperature of 28° F. to 30° F. for five months, temperature.

EGGS IN COLD STORAGE.

in a case along- with three dozen fresh eggs. After
three weeks no pronounced change was noted in
either, both showing- considerable evaporation as a
result of exposure to the dry fall atmosphere. They
were exposed to the temperature of the receiving-
room, fluctuating- from 50° F. to 80° F. The eg-g-s
from storage went throug-h a "sweat," while the fresh
were not subjected to any such trial. As most eggs
are consumed inside of three weeks after being re-
moved from storage, this would seem like a good
practical test of the vitality of a low temperature
egg. A mere matter of economy between holding a
room at 40° F. and 30° F., while readily appreciated
and admitted, seems of very small importance, when
a positive advantage can be obtained by carrying eggs
at the lower temperature; and a difference of 4° F. to
5° F. would be scarcely worth considering.

ui°re fc relents" ^n a(l vantage °f l°w temperature, not yet men-
"spot" rotten tioned, is the increased stiffness, or thickness, of the
white of the egg while in storage, holding the yolk in
more perfect suspension. When eggs are held at a
temperature of 36° F., or above, for any period longer
than four months, the yolk has a decided tendency to
rise and stick to the shell, causing rotten eggs, known
as "spots." It is usually understood that the yolk set-
tles; but, being of a fatty composition, it is lighter than
the albumen, and rises instead. If the albumen is
maintained in a heavy consistency, the yolk is retarded
from rising, and held in a more central position. It
was long a practice with storage men to turn eggs at
least once during the season, to prevent the above
trouble, and some recommend it even now; but the
practice has been generally abandoned with the ad-
vent of low temperatures for egg storing.

When eggs are put in cold storage they should not
be cooled rapidly. The effect on the egg tissues is
bad — they should have time to rearrange themselves
to the changed temperature. This is especially true

from storage,

EGGS IN COLD STORAGE. 17

where egg's are placed in storage in extreme warm
weather. Sudden warming is also detrimental to the
welfare of an egg, for a similar reason to above. The
most noticeable effect of either is a thinned albumen.
If this process of cooling and warming could be prac-
ticed carefully (which is not always practicable com-
mercially), a well kept storage egg would' come out of
storage with nearly the same vitality it had when fresh.

Data available
on humidity
practically
nothing-.

Evaporation
and mold can
be prevented.

Questions
relating- to
humidity.

CHAPTER II.

HUMIDITY.

INFORMATION on the subject of humidity, as
J. applied to the cold storage of eggs, is very meager.
Not more than a dozen of the replies received in
answer to the li& t of inquiries sent out contain infor-
mation on the three queries under the head of hu-
midity. Considering the amount of talk we have all
heard, with dry air as a subject, this scarcity of knowl-
edge is rather surprising. Those who have had ex-
perience with cold storage work and the products
handled are well aware that an essential for good re-
sults in egg refrigeration is a dry atmosphere in the
egg room ; but just how dry, very few are able to give
even an approximate estimate. Very likely if a cold
storage man is asked in regard to it, he will reply
that an egg room should be "neither too moist nor
too dry." What this "happy medium " is, that will
not shrink or evaporate the eggs badly, and yet keep
down the growth of fungus to a minimum, is what all
are striving for, and very few have the means of
knowing when this point is reached. A few years
ago a prominent commission man, in conversation
with the writer, speaking of storage eggs, said :
"You storage men are between the devil and the
deep sea. You always shrink 'em or stink 'em";
meaning that eggs which" were held long in storage
would show either a considerable evaporation or a
radical " musty " flavor. To some extent this is true,
but with a penetrat-ing circulation, careful ventilation
and a judicious use of absorbents (all of which will
be considered under their proper heads) egg can be,
and are, turned out of storage without this strong,
foreign flavor, and with little evaporation or shrinkage.
The questions relating to humidity were written
with a full understanding of the scarcity of informa-
tion on the subject, and were designed to locate, if

EGGS IN COLD STORAGE. 19

possible, those who were making* tests of air moist-
ure, and get opinions on the correct humidity for a
given temperature. The following- are the queries:

First. — What tests, if any, have you made of the
dryness or humidity of your egg rooms?

Second. — What per cent of air moisture do you find
gives the best results at the temperature you use?

Third. — What instrument do you use for testing
air moisture?

Questions 1 and 3 are practically the same, the
latter being written simply to make the query more
plain and indicate whether an instrument or some
other test was used for determining air moisture.
Four houses reporting are using the dry and wet bulb
thermometers; the others are using hygrometers of
French or German make.

The answers to question 2 vary greatly ; some
also giving the actual testing humidity of their rooms humidity.
and their opinion of a correct degree as well. From
70 to 80 per cent of humidity is the test of nearly all
reporting, and of the rooms tested by the writer,
nearly all show a similar humidity, with one occasion-
ally going as high as 85 per cent, and some as low as
65 per cent. Two answers recommend a humidity
of 65 per cent, and one a humidity of 60 per cent,
with a temperature of 30° F. to 32° F. Others hold
that their testing humidity of 70 to 80 per cent is
correct. The matter of correct humidity will be dis-
cussed further on.

The humidity of a room depends on the season
a moderate extent, and the condition of the room, as humidity.
regards ventilation, in some cases. In late fall or
winter, especially, if air is taken directly into the
room from the outside, the humidity will be low. As
cool weather approaches, the tendency is for the
humidity to rise, and unless kept down by ventilation
or by the use of absorbents, serious consequences are
sure to follow.

EGGS IN COLD STORAGE.

what relative To enable us to thoroughly understand the mean-
humidity . J
signifies. mg- of relative humidity, as it is called, we will study

a few extracts from " Instructions to Voluntary Ob-
servers," issued by the Weather Bureau at Washing--
ton, D. C. Humidity is considered on a decimal scale,
with 100 the saturation point of the air, at which it
will hold no more water vapor, and 0 the point at
which air contains no moisture whatever. The vari-
ous percentag-es between these points is a degree of
humidity relative to these two extremes, or relative
humidity. The quotations below are not contained
in the recent issue of instructions, but are from the
issue of 1892, which is now superseded by that of 1897.

Quoted from
"Instructions
to Weather
Observers."

WATER VAPOR IN AIR.

The air contains vapor of water, transparent and color-
less like its other g-aseous components. It only becomes visible
on condensing to fog" or cloud, which is only water in a fine
state of division. The amount is very variable at different
times, even in the vicinity of the ocean. The amount of moisture
that can exist as vapor in the air depends on the temperature.
There is a certain pressure of vapor, corresponding- to every
temperature, which cannot be exceeded ; beyond this there is
condensation. This temperature is called the temperature of
saturation for the pressure. When the temperature of the air
diminishes until the saturation temperature for the vapor con-
tained is reached, any further fall causes a condensation of
moisture. The temperature at which this occurs is called the
dew point temperature of the air at that time. The less the
quantity of moisture the air contains, the lower will be the
temperature of the dew point. For different saturation temper-
atures, the weight of vapor, in grains, contained in a cubic
foot of air is as follows:

Temperature of
Saturation, Degrees F.

0
10
20
30
40
50
60
70
80
90
100

Weig-ht in a
Cubic Foot, Grains.

0.56

0.87

1.32

1.96

2.85

4.08

5.74

7.98
10.93
14.79
19.77

EGGS IN COLD STORAGE. 21

The air is never perfectly saturated, not even when rain
is falling-; neither is it ever perfectly dry at any place. Rela-
tive humidity expresses relative amount of moisture in the air
only as long as the temperature of the air remains constant.
For this reason relative humidity is an imperfect datum. At a
low temperature, even a high relative humidity represents a
very small amount of vapor actually in the air, while a low
relative humidity at a high temperature represents a great
deal.

The most important law relating- to above concise
statements, and one which, if carefully noted and
applied, will make, all work in humidity easily under-
stood, is best expressed thus: The capacity of air for
moisture is increased with its temperature.*

At a temperature of 40° F., air will hold in sus-
pension more water vapor than at any lower tempera-
ture (see table); and when the difference is as much
as 10° F., the difference in the amount of moisture
the air will hold is very considerable. To illustrate:
Air which is saturated with moisture at 30° F., when
raised in temperature to 40° F., then holds but 68 per
cent of its total capacity.

Under the head of "Temperature," it is stated . th

that: "If eggs are held at a temperature of 30° F. in
an atmosphere of a given humidity, the growth of
fungus is less rapid than if held at any temperature
higher, with the same per cent of humidity. Refer-
ring again to the table, we see that a cubic foot of air,
when saturated at a temperatureof 40° F.,contains2. 85
grainsof water vapor, while at 30°F. it contains but 1.96
grains, or only about two-thirds as much as at 40° F.
The same holds true with any relative humidity, the
same as when the air is saturated. Take, for instance,
air at a temperature of 40° F., with a humidity of 75
per cent, then a cubic foot of air holds 2.14 grains of
water vapor per cubic foot; and at a temperature of

* Strictly speaking, air has no capacity for moisture, the water vapor being
simply diffused through the air, after the nature of a mechanical mixture. For
all practical purpases, we may regard it as being absorbed by the air, and it is
usually so treated.

22 EGGS IN COLD STOKAGK.

30° F., with the same relative humidity, it would hold
but 1.47 grains. This great difference in the amount
of moisture contained in the air at different temper-
atures, and still having the same relative humidity,
has as radical an effect on the growth of fungus
as does the difference in temperature. This is no
mere theory, as the writer has demonstrated it, to his
own satisfaction, at least, during- several seasons'
observation. If it is hoped to keep down the growth
of fungus in a temperature of 40° F. by maintaining an
Result of too atmosphere with a lower relative humidity, the result
r<Smanef?? is a badly evaporated egg, which loses its vitality and
value very rapidly when held in storage for a term
exceeding three or four months; the white becomes
thin and watery, with a strong tendency to develop
"spot" rotten eggs. As the fullness or absence of
evaporation is of only secondary consideration to their
sweetness, when eggs are tested by buyers, it is
necessary to prevent this trouble if the eggs turned
out from storage are to be considered first-class.
humwitry lnotv& From the foregoing it seems clear that to turn out
sweet eggs at a temperature of 40° F. it is necessary
to maintain a lower relative humidity than at any tem-
perature lower, and the result cannot fail to be as de-
scribed. The writer has already given a summary of
the replies to the questions relating to humidity, which
are few in number, and not very complete. A little
is better than nothing, however, and by comparing
his own data with the results obtained by others, and
paying careful attention to their opinions, the follow-
ing table of correct humidity for a given temperature
in egg rooms has been compiled. There are no data on
the subject in print, so far as known, and no claim for
absolute accuracy is made in presenting this first
effort in that direction, but as the figures are taken
from actual results, no great mistake can be made by
depending on them. The percentages of humidity
given are modified, to some extent, by the intensity

EGGS IN COLD STORAGE. 23

and distribution of the air circulation employed. (See
Chapter III on "Circulation.")

CORRECT RELATIVE HUMIDITY FOR A GIVEN TEMPERATURE
IN EGG ROOMS.

Temperature Relative Humidity, Humidity table

in Decrees F. Per Cent. for egg rooms.

29 78

30 76

31 74

32 71

33 69

34 67

35 65

36 62

37 60

38 58

39 56

40 53

There are two kinds of instruments in use for de- Hygrometers.
termining- humidity, hygrometersand psychrometers.
The hygrometer depends on the expansion and con-
traction of some substance, as a human hair, in the
presence of more or less moisture in the air. The
hair used is fastened at one end, the other end passing-
around a pulley, to which is fastened a pointer, which
moves over a graduated arc as the hair chang-es its
leng-th. The scale reads from 0 to 100. The chief
advantag-e of these instruments is that results are
obtained at once, the reading- corresponding- to the
percentag-e of saturation or relative humidity; but
these instruments are affected by chang-es of tem-
perature, and shocks or vibration materially affect
the reading-. Further, they are more expensive in
first cost, and not so convenient to use, as they must
hang- for some time in the room to be tested, while
with the sling psychrometer, described in another
paragraph, an observer can pass from room to room,
g-etting- observation in less than two minutes in each
room, needing- but one instrument and making- all
observations at practically the same time.

A psychrometer is simply two thermometers Psychrometers.
mounted on a frame ; the bulb of one being- covered

24 KGGS IN COLD STORAGE.

with rnuslin so as to retain a film of water surround-
ing it. The working- of this instrument depends on
a law which may be roughly expressed, as "evapora-
tion carries off heat." The evaporation of water from
the bulb incased in muslin, known as the wet bulb,
cools it somewhat, depending- on how dry the air sur-
rounding- it may be. The difference between the
reading- of the wet bulb thermometer and the reading
of the dry bulb thermometer, when compared with
reference to a prepared table, give's the relative
humidity of the air at the time of making- the observa-
tion. Psych rometers are of two kinds, stationary
and sling-.

The stati°nary psychrometer is essentially like
the sling- psychrometer, both depending- on the same
principle. The sling- instrument is more compact
and provided with a handle for whirling-, while the
stationary instrument is intended to be fastened
against the wall, or on a post, the muslin covering- the
wet bulb being connected by a porous cord with a
reservoir of water, to keep the supply of water con-
tinuous. This is essential, as it takes some little
time to obtain a correct reading with this pattern of
instrument. For this reason it is open to the same
objections as the hygrometer. Also, after short use
the muslin covering the wet bulb, and the cord feed-
ing water to it, become clogged with solid matter and
fungous growth affecting its accuracy. At any tem-
perature below 32° F. this instrument is useless, as
the water will freeze in the cord supplying the mus-
lin on the wet bulb, and the muslin becomes dry in
consequence.

For practical, accurate and quick results at any

psychrometer. .

temperature there is no instrument so reliable and
convenient as the sling psychrometer, preferably of
the pattern known as Prof. Marvin's improved psy-
chrometer, shown in the illustration. This is a
standard Weather Bureau instrument, and when used

EGGS IN COLD STORAGE.

in connection with the tables of hu-
midity published by the bureau, any
needed results may be obtained with
a fair degree of accuracy. The sling
psychrometer, as illustrated, consists
of a pair of thermometers mounted
on an aluminum plate, one higher
than the other, the lower having- its
bulb covered with a small sack of
muslin. At the«top, the frame or plate
supporting- the thermometers is pro-
vided with a handle for whirling-, this handle
being- connected by links to the plate, and
provided with a swivel to allow of a smooth
rotary motion. The bulb of the lower ther-
mometer is wet at the time of making- an ob-
servation, Ihe muslin serving- to retain a film
of water, surrounding- and in contact with
what is known as the wet bulb of the psy-
chrometer. The muslin should be renewed
from time to time, as the meshes between the
threads will gradually fill with solid matter
left by the evaporation of the water and the
natural accumulation of dust from the air.
The muslin in this condition will neither ab-
sorb nor evaporate the water readily.

To make an observation dip the muslinDirectionsfor

using1 the sling

covered bulb in a small cup or other wide-Psychrometer-
mouthed receptacle containing- water. Whirl
the thermometer for ten or fifteen seconds,
then dip the wet bulb of the psychrcmeter
into the water again. Whirl again for ten or
fifteen seconds, stop and read quickly, read-
ing- the wet bulb first. Repeat once or twice,
noting- the reading- each time. When two
successive readings of the wet bulb agree
very nearly, the lowest point has been
Dip the wet bulb only after the

SLING
PSYCHRO-
METER. -reached.

26 EGGS IN COLD STORAGE.

first whirling, as this is done only to make sure
that the muslin is thoroughly saturated with water.
If the water used is of nearly the same temperature
as the room, correct readings are sooner obtained.
If the psychrometer and water are at a much higher
temperature than the air of the room, it will take a
proportionately longer time to reach a correct read-
ing, but the accuracy will not be impaired, if sufficient
time is allowed for the mercury to settle. It is very
important that the muslin covered bulb should not
become dry in the least; it should be saturated with
water during the full time of observation. There will
be no difficulty in getting accurate readings down to
29° F., as indicated by the dry bulb. At about this
temperature, and with the wet bulb at about 27° F.,
ice will form on the wet bulb and cause the psychro-
meter to become somewhat erratic in its behavior.*

Jt is difficult to describe the proper movements
psychrometer. for whirling the sling psychrometer, a little practice
being the best instructor. The handle is held in
a horizontal position, the frame mounting the ther-
mometers revolving around the pivot, after the man-
ner of the weapon with which David slew Goliath, and
from which our moisture-tester gets the easy part
of its name. A high rate of speed is unnecessary, a
natural, easy motion of the forearm or wrist being all
that is required. When stopping the psychrometer
the arm should follow the thermometer from the high-
est point of the circle of rotation, whereby the radius
of the path of the psychrometer is increased, and the
momentum overcome. The stopping can be accom-
plished in a single revolution, after a little practice.
The psychrometer will come to rest very nicely by
simply allowing the arm to stand still, but the final
revolution will be quite irregular and jerky.

* The writer is in receipt of a special report on this point, prepared by
Prof. C. F. Marvin, in charge of the instrument division of the Weather Bureau,
and will gladly give any one having difficulty with the psychrometer at these
temperatures information so far as he can; but the point involved is somewhat
intricate, and so few are using temperatures as low as 29° F. that it is thought
best to omit a discussion of this phenomenon.

EGGS IN COLD STORAGE.

In making- observation in a storage room, the psy-
chrometer should be held as far as convenient from
the body, and toward the direction from which the
circulation comes — the observer standing- to the lee-
ward, as it were. In some cases it is necessary, or
advisable, to step slowly back and forth a few steps,
and the observer should turn his head from the di-
rection of the psychrometer, so his breath will not
affect the reading. In reading- a thermometer, read
as quickly as possible, and do not allow the breath to
strike the bulb. It is a common practice with the
writer to hold his breath while reading a thermome-
ter. It is unnecessary to caution ag-ainst allowing- the
psychrometer to strike any object while whirling*.
In case it should, the observer will have $5 worth of
experience, but no psychrometer.

RELATIVE HUMIDITY, PER CENT.

Difference between the dry and wet thermometers (t—f).

£ Table of rela-
v tive humidity.

•K.-*-1

0°.5

1°.0

1°.5

2°.0

2°.5

3°.0

3°.5

4°.0

4°.5

5°.0

5°.S

6°.0

77'

7.9

77,

59l

80,

8ll

40 i

The above short table needs no explanation fur-
ther than has been already given. It will cover any
case in egg room observations. This table was not
intended for cold storag-e work, being- a part of the
regular humidity tables published by the Weather
Bureau. The full set of tables can be had by

table

28 EGGS IN COLD STORAGE.

addressing- the chief of the Weather Bureau, Depart-
ment of Agriculture, Washington, D. C. They are
published in pamphlet form, along1 with tables giving-
dew point temperatures. Observers must work out
the small fractions for themselves, if they think
necessary, but results within the limits covered by
the table are near enough for present practical pur-
poses.

It is of no use to test for moisture unless having*
the ability to control it, any more than a thermometer
would be of use unless the means of regulating* tem-
perature were at hand. Humidity can be controlled
by ventilation and the use of absorbents, which are
considered elsewhere.

V'J

CHAPTER III.

CIRCULATION.

vigorous and penetrating* circulation of air must circulation

* . . essential.

be maintained in a cold storage room for eggs if
good results are to be insured. The importance of
this condition, as applied to eggs especially, is quite
generally appreciated, and it is noticeable that the
warehouses producing the most perfect work have
scientific and carefully designed air circulating sys-
tems. It is also a fact that a strong, searching circu-
lation will do much to counteract defects in a cooling
apparatus, or wrong conditions in the egg room in
some other particular. In proof of this, the writer is
familiar with a number of successful houses where
prominence is made of the air circulating system
only, some of the other conditions being neglected al-
together, or attended to in a perfunctory manner.

Before going farther, it is best that we separate circulation n

0 * . ventilation.

circulation from its tangle with ventilation. These
two terms are quite commonly confused when applied
to cold storage work. Circulation, as here discussed,
applies to the motion of air within the storage room —
air currents resulting from a difference in tempera-
ture of the air in different parts of the room, or the
result of mechanical force applied to the air by use of
fans, blowers or exhausters. In distinction from cir-
culation, ventilation means the renewal of the air of a
storage room, either by forcing fresh air from the
outside atmosphere into the storage room, or by ex-
hausting the foul air from the room. Ventilation is
not under consideration here, but will be taken up as
a separate subject.

The reason why a vigorous and well distributed circulation

~ ^ and moisture

circulation of air in an egg room will give superior absorbing
results over a sluggish or partial circulation may not
be readily apparent. A circulation of air is of benefit
in combination with moisture absorbing capacity in

30 EGGS IN COLD STORAGE.

the form of frozen surfaces or deliquescent chemicals.
Stirring- up the air merely, as with an electric motor
fan, without provision for extracting- the moisture, is
of doubtful utility, and may, in some instances, prove
positively detrimental, as it is liable to cause conden-
sation of moisture on the goods, or walls of storag-e
room, instead of its correct resting- place: the cooling-
coils and absorbents. Let us see how the circulation of
air in a storag-e room operates to benefit its condition.
Under head of temperature, we have seen that
circulation. foQ evaporation from an eg-g- contains the putrid ele-
ments resulting- from a partial decomposition of the
eg-g- tissues, and that the air of a storag-e room carries
them in suspension. It is probable that these foul
elements are partly in the form of g-ases absorbed in
the moisture thrown off from the egg-; and if, there-
fore, this moisture is promptly frozen on the cooling-
pipes, or absorbed by chemicals, the poisonous gases
and products of decomposition are very largely ren-
dered harmless. This is also true of the germs
which produce mold and hasten decay, which are ever
present in the atmosphere of a storage room, being
carried to a considerable extent by the water vapor
in the air, along with the foul matter of various kinds
referred to. If the vapor laden air surrounding an
egg is not removed and fresh air supplied in its place,
the air in the immediate vicinity of the egg gets fully
charged with elements which will produce a growth of
fungus on its exterior, affecting and flavoring the in-
terior— the flavor varying in intensity, depending on
how thoroughly impregnated with fungus-producing
vapor the air in which the egg is kept may be. In
short, then, circulation is of value because it assists
in purifying the air. It should be kept up so that
the air may be constantly undergoing a purifying
process to free it from the effluvia which are always
being thrown off by the eggs, even at very low tem-
peratures. It has been suggested that a brisk circu-

EGGS IN COLD STORAGE. 31

lation of air which will keep in motion the whole
volume of air in the storage room will have a purify-
ing- influence independent of any moisture absorb-
ing- capacity, but no satisfactory reason has been
assig-ned. There may be such an influence opera-
tive when the air is mechanically circulated. If so,
there seems to be no scientific or practical explana-
tion of it.

Manv patents have been granted for improve- circulation in

0 A natural ice

ments in storag-e rooms or refrig-erators using- ice only refrigerators.
for a cooling- ag-ent; house refrig-erators, refrigerator
cars and refrigerator buildings are represented in
number about in order named. A large portion of the
patents granted have been on claims for the improve-
ment of circulation, and this is the keynote of what-
ever success has been attained by the various sys-
tems which use ice only for cooling. As any system
of cooling whereby the air is caused to circulate in
contact with melting ice is now quite generally re-
garded as obsolete for the successful refrigeration of
eggs for long period storage, a discussion of the
merits of the various devices applied to this work
will be omitted.* It may be said to their credit, how-
ever, that the builders of ice refrigerators have orig-
inated ideas on circulation which have been of much
value to the present-day refrigerating engineers, and
there are still those who may obtain good information
from this source — the provision for circulation (or
rather, lack of circulation) in a few of the new me-
chanical cold storage houses being simply ridiculous.
In the more progressive mechanically refrigerated
houses there are a number of devices, which have
been introduced for assisting natural gravity air cir-
culation, also the various modifications of the me-

* The above must not be construed as condemning- the use of ice as a
refrigerant when rightly applied. The writer has in successful operation a sys-
tem of gravity brine circulation, cooled by ice and salt, with which he will under-
take to produce at moderate expense any possible results in refrigeration down
to a temperature of 15" F.

KGGS IN COLD STORAGE.

Questions
rel atinar to
circulation.

Answers to
Query 1.

chanical forced circulation system. Some of these
will continue to gain favor because of the improved
results obtained by their use. The main requisite
in any air circulating- system is an ability to cause an
equal distribution of the moving- air, as it comes from
the moisture absorbing- surfaces, forcing it uniformly
to all parts of the room and compelling- it to flow
throug-h and around the. piles of stored g-oods. As a
secondary consideration may be mentioned the equal-
ization of temperature and humidity in all parts of the
room. The writer is somewhat biased in favor of
forced circulation, having- developed a very complete
system on this line, with some new features. Aside
from a matter of economy of space and operation,
the system employed matters little, if an effective cir-
culation is produced.

The questions bearing5 upon circulation contained
in the list of inquiries sent out by the writer are as
follows :

First. — In piping- your rooms what provision was
made for air circulation?

Second. — What difference in- temperature do you
notice in different parts of the same room?

Third. — Do you use a fan or any kind of mechanical
device for maintaining- a circulation of air in the rooms?

More answers were received on this subject than
on the subject of humidity, but not exceeding- one-
third contained tangible replies to all three inquiries.
Several of the answers confounded circulation with
ventilation, as before alluded to. Question 1, in par-
ticular, was badly neglected, indicating, no doubt, that
no provision was made for circulation in a majority of
cases. The common device in use for causing air to
circulate more rapidly over the cooling coils, when
they are placed directly in the room, is some form
of screen, mantle, apron, false ceiling or partition, as
illustrated in Figs. 3, 4 and 5. Many of these have
been put up after the house has been in operation for

EGGS IN COLD STORAGE. 33

some time, and are very crude affairs, applied in all
conceivable combinations with the pipe coils. In some
cases canvas curtains, or a thin wooden screen, have
been suspended under ceiling- coils with a slant to
cause the cold air to flow off one side, and with sur-
prising" improvement to the room, considering- the
simplicity of the device. Forced circulation with a
complete system of distributing- air ducts is coming
into g-eneral use, as the meritsof this way of producing
circulation are better understood and appreciated.

Query 2 was answered more generally, but that Answers to
some of the answers were mere guesses, or state-
ments made without testing, is very evident, as they
state that no difference was noticed in different parts
of the same room. With open piping or gravity air
circulation, this is an impossibility — it is only possible
with a perfectly designed forced circulation system.
In contrast to this claim some answers state a differ-
ence in temperature of as high as 4° F. to 5° F., but
most answers show a difference of 1° F. to 2° F.; a
few ^° F. to 1° F.; and, still others, as before stated,
none at all. A marked variation of temperature in
different parts of a room, while in most cases caused
by defective circulation, is due sometimes partly to
location of room as to outside exposure, proximity to
freezing rooms, character of the insulating walls, etc.
An egg room placed over a low temperature freezing
room will show more variation between floor and
ceiling than when located over another egg room,
conditions being otherwise the same. Where this
arrangement occurs, and the egg rooms are operated
on a natural gravity air circulation system, eggs may
be frozen near the floor, when a thermometer hanging
at the height of a person's eyes would read 30° F. or
above. Even with the very best insulation, the result
of this very common arrangement is a defective cir-
culation and more or less variation in temperature
between floor and ceiling.

EGGS IN COLD STORAGE.

Answers to
Query 3.

Gravity air
circulation.

In reply to Question 3, about a dozen state that
they are using- some form of mechanical forced cir-
culation. The advantages of this method will be
discussed quite fully later on. About double this
number are using- the small electric fans. These
also will be treated in the discussion of mechanical
air circulation in another chapter.

As air circulation is a somewhat neglected subject,
and comparatively few have experimented enough to
have positive opinions, based upon practical expe-
rience, reg-arding- the merits of different devices and
methods, some of the more prominent and successful
ones are illustrated and discussed in this article.

In considering- the following- outlined arrange-
ments of piping- in the storag-e room and the various
locations of screens, partitions, etc., in combination
with the coils, for the purpose of separating- the
warm and cold currents of air (the one on its way
upward from lower part of room to the top of
cooling- coils; the other downward from cooling-
coil toward floor), the principle on which this
movement of air operates should be noted, so
that the underlying- law may be understood. The
cause of a circulation of air in a storag-e room with
direct piping- is a variation of temperature, which
causes a difference in weig-ht of the air in different
portions of the room. The air in the immediate
vicinity of the pipes is cooled to a lower temperature
than in the balance of the room, causing- it to drop
toward the floor by reason of its greater specific
gravity — what is designated as gravity air circulation.
Just as long- as the flow of the refrig-erant is main-
tained within the cooling- pipes, the air will circulate
by the action of gravity, the lig-hter warm air in top
of room descending- to replace the air in contact with
pipes, which falls, as cooled, toward the floor. Should
the refrig-erant passing- through coils be shut off, the
cooling effect is checked, and as a result air circula-

EGGS IN COLD STORAGE. 35

tion over the pipes ceases. This should make plain
the fact that uniform temperatures in all parts of the
room are not even an approximate possibility in any
room depending- on natural gravity air circulation. It
may also be observed that the eg-g-s exposed to the
flow of cold air near bottom of coils will stand in a
dryer and colder atmosphere than those in top and
center of room.

Fig-. 1 shows an outline sketch of piping- suspende
from the ceiling- of a room — the most unscientific way
possible for a room to be piped, as it provides for no

* "

) ' f j*f

v j ^ ^ J ; ( V j ^ s

air circulation whatever. The only possible reason
why air will circulate over pipes in this position is be-
cause of the fact that the whole ceiling- is not covered
by pipes, which allows of a partial circulation, as
shown by the arrows. The volume of circulation in
the lower half of room is practically nothing-. It is
larg-ely confined to the top of room, the lower part
being- cooled by conduction and radiation almost en-
tirely. It may be asked : How can a room be cooled
by radiation? In the same way that a room is heated
by radiation, except that in cooling- a room the heat is
radiated_/>wft the objects in the room, and not to them,
as when heating-. This gives us ample reason why a
room should be cooled by circulating- the air over

EGGS IN COLD STORAGE.

Open side wall
Piping.

frozen surfaces located outside of the room, or at
least in a position so that no radiation or conduction
can occur. The use of insulated screens or mantles,
as shown in Figs. 3, 4. and 5, is recommended as being-
superior to any arrangement of open piping-; but, of
course, it is not equal to forced circulation, in which
the pipes are located outside of room entirely.

Fig-. 2 shows another very common and faulty
arrang-ement of piping for cooling an egg room. The
only improvement over the arrangement shown in
Fig. 1 is that it allows of a moderate action of gravity

f (

near the coils, as shown by the arrows. It is open to
the same objection on the ground of conduction and
radiation as No. 1, but to a lesser degree. The coils
are placed a few inches out from the walls, to allow
the air to circulate around the pipes freely, and to
provide room for an accumulation of frost. The top
of the coil should be quite close to the ceiling. If the
coil is placed, say midway between floor and ceiling
(unless it covers nearly the whole space), it is sure to
result in the air becoming stratified, a warm layer of
air in top of room resting on a colder one near floor,
perhaps to an extent so great as to cause a difference
of 10° F. in temperature between floor and ceiling of
room. A case with exactlv these conditions is on

EGGS IN COLD STORAGE.

record. Another very bad arrangement of side wall
piping- came to the notice of the writer recently. A
room exceeding- fifty feet square was piped completely
around from floor to ceiling with the exception of the
doors. Circulation could penetrate but a compara-
tively small portion of the space in this room, and in
a large area of the central portion the air was conse-
quently very foul, and mold and must were rampant.

Fig. 3 gives us the first primitive improvement A
over open coils, and it is along step in the right direc-pipin£
tion, but it fails to take care of the center of the room,

/'/>

f/j.

especially near the ceiling. The usefulness of this
device consists in its ability to increase the velocity,
and consequently the volume of air passing over the
cooling coils. The increased velocity of air causes it
to cover a greater area, and spread toward the center
of room further. The apron or screen used before
the coils should be constructed of any moderately
good non-conductor. Separating the warm and cold
currents of air increases the draft, on the same prin-
ciple that a fire burning in a flue creates a greater
suction or a more rapid displacement of air than when
burning in the open.

Fig. 4 is simply an addition to No. 3, of a false
ceiling or curtain extending well out toward the

KGGS IN COLD STORAGE.

Gay's system
of box coils.

center of the room. This obliges the circulation to
spread so as to cover a large portion of the cross-sec-
tion area of the room, as indicated by the arrows, but
has the effect of reducing its volume to some extent.
This ceiling apron should have a slant of not less than
one foot in ten. It occupies some considerable space,
but is richly worth it. The opening into outer edge
of apron in center of room need not exceed three
inches in depth in most cases, and, as some space
must be left at the top of room for air circulation

with the wall coils, without ceiling apron, not much
space is wasted by its addition.

Fig. 5 gives us an entirely different arrangement
of piping, but with essentially the arrangement of
aprons shown in Fig. 4. This is the system advo-
cated by Mr. C. M. Gay on page 106 of the August,
1897, number of Ice and Refrigeration, and the
writer believes it to be the best idea for air circula-
tion of any having pipes directly in the room. The
following is quoted from Mr. Gay's description:
" Upper pipes of box coils should be about ten inches
below the ceiling of the room, to prevent sweating.
When brine or ammonia is turned into these pipes
(as shown in Fig. 5), the cold air around the pipes
seeks an outlet downward and passes between the

EGGS IN COLD STORAGE.

false partition and the side wall of the room, thus
displacing- or pushing- along- the air in center of room,
the cold air naturally seeking- the lowest point and the
warm air the hig-hest point, each by reason of its rela-
tive gravity. Thus as the cold air falls from the cool-
ing- surfaces it is replaced by the warm air from
hig-hest point in center of room. This secures a
natural circulation and a dry room, there being- no
counter-currents nor tendency to precipitate moisture
on walls or ceiling-."

Fie-. 6 is the St. Clair or pipe loft system, which st. ciair, or

i_ 1-jj j i j t. j • Pipe loft

has been applied to many remodeled overhead ice system,
cold storag-es, by placing- the pipes in a part of what
formerly was the ice space, and, in some cases, using-
the original air ducts for circulation. The sketch
here shown represents one room only, but as many as
five or six different floors have been operated from a
single pipe loft, using- one main air duct for the down,
and one for return air circulation, each floor having- a
connection with the mains in which the flow of air is
reg-ulated by g-ates. A better arrang-ement, when
more than one floor is to be operated on this system,
is to have independent ducts for each room, and the
cooling- coils separated likewise; then any room or
rooms may be used for other products at any time

EGGS IN COLD STORAGE.

Size of
egg rooms.

when free of eggs. This latter arrangement, of
course, requires more space and is slightly objection-
able on this account. The circulation is more vigor-
ous with this system than with any pipe-in-the-room
system, depending- on the law that the higher the
column of air the stronger the draft, on the same
principle that a tall chimney gives
greater draft than a short one. It is,
therefore, better than any room pip-
ing, and has the added advantage of

f /

being easily shut off from the room, when the weather
no longer requires cooling power. The need of keep-
ing the air of the room from contact with the frost
on pipes will be looked into under ventilation and
absorbents.

Refrigerator rooms for the storage of eggs should
not exceed thirty or thirty-five feet in width. The
cross-section illustrations of rooms cooled by gravity
air circulation, which have already been illustrated, and
the two sketches shown herewith of the arrangement
of air distributing ducts used in two systems of forced
circulation, are sufficient to show why a room should
not be excessively wide as compared to its height. In
a wide room it may be seen that the air from cold
air ducts, in case^of forced circulation, or from the

BGGS IN COLD STORAGE. 41

bottom of cooling- coils in case of room piping-, is
required to pass over more eggs in its flow to the
return air duct or false ceiling-. The eg-g-s, then,
are not all exposed to the same drying- and puri-
fying- influence, because the air as it comes from the
cooling- coils is at its maximum dryness and purity,
and becomes impregnated with moisture and impuri-
ties more and more as it flows through the goods. If
the length of piles of goods is great from side to cen-
ter of room, the eggs in top and center of room will be
exposed to air which is much more impure and moist
than the eggs first exposed to the flow of air directly
from cooling coils. This applies more especially to
the gravity systems of air circulation. With forced
circulation, the air moves probably three or four
times as fast as when a gravity system is used, con-
sequently the air in top and center of room does not
carry the amount of impurities that it does if depend-
ing only on gravity for its motion. This fact in itself
is a very good reason why forced circulation is supe-
rior to any gravity system.

It has been claimed that eggs will lose weight by
shrinkage more rapidly when stored in a room iH
which the air is circulated by mechanical means than
in a room operated on the gravity air circulation prin-
ciple. This assertion is based on the assumption
that the air is circulated at a much higher velocity
when forced circulation is employed, and is only
partly true because no account is taken of humidity.
If the humidity was the same in both cases, the claim
would be strictly true. Every intelligent housewife
knows that linen hung in the open air to dry, will be
freed of moisture quicker when a strong breeze is
blowing, than when the air is nearly still. The same
principle applies moderately to eggs in a refrigerator
room. With the same per cent of moisture, the more
rapid the circulation the greater the evaporation from
the eggs; but if the facts were known, it would be

42 KGGS IN COLD STORAGE.

found in every instance where trouble from excessive
shrinkage of the egg meat was experienced, that no
attempt was made to regulate humidity. It is as easy
to control humidity as it is to control temperature, and
with no bad effect on the other conditions in the storage
room, if we go about it in the right way. Ventilation
and the use of absorbents are agents which can be
utilized for this purpose.

toie With a vigorous circulation of air, an egg room may
circulation. be maintained at a humidity which would be disas-
trous, if only a sluggish circulation was operative.
Why? Because a brisk movement of air around the
eggs removes the moisture and impurities as fast as
given off by the eggs. They are not allowed to remain
in the vicinity of the eggs to work mischief, but are
promptly hurried off to the cooling coils or absorb-
ents, where they are, for the most part, rendered
harmless. This seems to explain how eggs may be
carried sweet, and with very little evaporation, when a
well distributed forced circulation of air is employed.
With any gravity system, the circulation of air can-
not be controlled, because depending on the tempera-
ture of refrigerant flowing in the pipes for its velocity;
and as the temperature of refrigerant is regulated to
correspond with outside weather conditions (lower in
warm weather and higher in cold weather) the velocity
of circulation is not constant — being least in the cold
weather of fall, when it is most needed. With a good
system of forced circulation installed, the problem,
then, is to proportion the circulation of air to the
humidity. We might take our humidity at the degree
which would come naturally, if no attempt were made
to control it, and speed our blower up or down to pro-
duce a circulation to match, but it would probably be
best to provide a circulation which would handle a
large volume of air at a brisk speed, and raise our
humidity to as high a point as would be safe. Refer-
ring to the table of correct humidity given in Chapter

EGGS IN COLD STORAGE. 43

II, page 23, it will be noted that an arbitrary
percentage is given for each temperature. These
are the most desirable percentages of air moisture
for average conditions of circulation, as when using
the most scientific forms of gravity air circulation
during warm weather. When using a good system
of forced circulation, these percentages may be in-
creased moderately. Exactly how much will depend
on conditions, and can be told only by trial, but it will
be much greater in proportion at the high tempera-
tures, ranging from 2 per cent or 3 per cent on the low,
to 7 per cent or 8 per cent on higher temperatures.

Before taking up the forced circulation systems Electric fan in

egg room not

proper, the electric fans used in so many large houses desirable.
will be considered. These little fans are a four to
six-bladed disk fan, from twelve to eighteen inches in
diameter, attached directly to the shaft of a J/s or
^ -horse power electric motor. /The wires supplying
the electric current to the motor are usually con-
nected to the socket for an ordinary incandescent
lamp. Electric fans are usually placed on the floor
in the back end of alleyway, or in an opening in the
piles of goods, creating a draft of air from one ex-
tremity of the room toward the other. As the air
from the fan will follow a path of least resistance, the
circulation resulting from their operation is largely
confined to the alleyways or openings in the piles of
stored goods — it does not penetrate through and be-
hind the piles of eggs. It may be readily observed
that this is of doubtful utility, and may at times lead
to positive harm by causing a condensation of mois-
ture upon goods as a result of the comparatively
warm, moisture laden upper strata of air coming in
contact with the flow of cold air from the cooling
pipes. Electric fans have also been utilized to propel
the air from the cooling pipes, for which purpose they
are placed in an opening in a screen or mantle cover-
ing the pipes, forcing the cooled air outwardly into the

44 EGGS IN COLD STORAGE.

room. In any other position, they are only useful as a
"talking* point," as it is likely to impress a prospective
customer favorably with the cooling- power of a refrig-
erator, to allow him to stand for a few seconds in the
breeze created by one of these higii-speed fans. The
use of electric fans has been adopted to an extent not
warranted by the results possible to attain with them,
and their use will no doubt be gradually discontinued
as the fallacy of the idea becomes apparent.
Primitive The first svstem of true forced circulation to con-

torccQ a, ir •*

circulation. sider is not illustrated and needs no sketch to explain
the working- of it, as there are practically no distribut-
ing- air ducts, the cold air being- forced into the room
at two or three larg-e opening's, and taken out in the
same way. There are two prominent houses using
an air system constructed on these lines, one having
the cold air inlet near floor and warm air outlet near
ceiling-, the other having both cold and warm air open-
ings near ceiling. No distribution of circulating air
of any consequence is provided, the idea being simply
to cool the room by forcing in air which has been
cooled by coming in contact with cooling pipes located
outside of the rooms. The cold air is taken in at one
extremity of room and the warm air out at the other,
or the cold air is taken in at ends of room and warm
air out at center, or the reverse. This is what may
be called a primitive form of forced circulation, and is
quite similar to the systems of indirect steam heating
as first employed. It needs no argument to show that
a room equipped in this way has varying degrees of
temperature, humidity and circulation, depending on
the remoteness or proximity to the direct route be-
tween cold air inlet and warm air outlet — the air mov-
ing through the area of least resistance, which is
usually along the center alley of room.

Linde-British Fig. 7 shows the arrangement of ducts for air

air-circulation 3 .

system. circulation used in the Linde-British air system; a a,

cold air ducts; b b, warm air duct. This system of

EGGS IN COLD STORAGE. 45

refrigeration originated in Europe, and has found
favor to some extent on this side of the water, three
houses known to the writer being- operated on this
system. Mr. E. H. Johnson describes the apparatus
used in cooling, purifying and circulating the air on
page 96 of the February, 1898, issue of Ice and Refrig-
eration. This consists essentially of a tank containing
brine, which is cooled by direct expansion piping.
Slowly revolving in the tank, with a portion of their
surface exposed above the surface of the brine, are
large metallic disks. A fan causes the air to circu-

late rapidly over the brine moistened surfaces of the
disks, and the moisture is extracted, and impurities
and odors absorbed by the cold brine. In a modifica-
tion of this apparatus the direct expansion coils do the
cooling and take the place of the disks as well. The
coils are exposed to the air circulation, and the brine is
pumped over them in a shower, a shallow pan or tank
being provided under coils as a reservoir and recep-
tacle for the brine — the same brine flowing over coils
again and again. It has been claimed for this system
that almost any product can be stored in different
rooms, all of which were fed by the same air circuit
and cooling apparatus, without any injury to the most
sensitive. A statement of this kind must first be

EGGS IN COLD STORAGE.

proven before we can accept it. There is no doubt,
however, but that some good features are embodied
in above described apparatus. It is well known that
water, and especially salt water, has a great affinity
for impurities contained in the air, and when the air
is circulated in contact with the brine, as in the Linde
system, many of the gases and impurities common to
a storage room are absorbed. That they are ab-
sorbed to any greater extent than when the moisture
is simply frozen on the pipe coils, the writer is not
prepared to assert. An objection to this brine or wet
surface air cooling is the liability of trouble when
brine gets polluted with impurities. After some use
the brine will no longer act as a purifier, and in this
condition will contaminate, rather than purify, the
air. If attended to, this trouble can be prevented by
a periodical renewal, or by supplying a certain amount
of fresh brine at regular intervals and allowing a
portion to overflow. In discussing absorbents we
will find a description of a device which seems to have
all the advantages of the Linde method, and without
some of the objections.

The location of air ducts as adopted by the Linde-
British company seems to call for some attention. It
is evident from their location that gravity is depended
upon for a circulation of air near floor, as both warm
and cold air ducts are placed on ceiling of room. The
flow of air into room is controlled by means of sliding
gates, which are adjusted to openings placed five or
six feet apart in the air duct. This does not provide
a well distributed circulation, as those goods directly
opposite openings in cold air ducts will be exposed to
a sharp blast of air, while others get practically none.
As a result of placing the cold air duct on ceiling,
there will be little or no movement of the air near
floor, when rooms are filled with goods.

Fig. 8 shows a cross-section of a room fitted with
a system of air ducts and false ceiling for the circu-

EGGS IN COLD STORAGE.

lation of air in a cold storage room, which the writer
has developed after several seasons' experiment,
and which is regarded as very nearly theoretically
perfect. In practical working- it gives very superior
results, and is believed, by those who are using- it, to
be in advance of any other system now in use. By
referring- to the sketch it may be seen that the air is
forced to cover very uniformly the entire cross-sec-
tion area of the room — a result not possible with any
other device. This is obtained by the use of a false
ceiling, b b, perforated at intervals with small holes

/«

the "Cooper
system" of
forced air
circulation.

which covers the whole ceiling of room ; and the side
air duct, a a, perforated with small holes on top, bot-
tom and sides. The air from cooling coils is forced
into ducts, a a, and flows out through the perforations.
Passing through the piles of eggs, as shown by the
arrows, the air moves upward through the perfora-
tions in the false ceiling, and thence through space
between false ceiling and ceiling, to cooling coils
again. This circulation is actuated by an exhauster,
or blower, preferably located on the main cold air
duct, between the cooling coils and cold air ducts, a a.
This has a tendency to put the egg room itself under
a slight pressure, and the coil room under a vacuum.
In this way the air leakage from outside, if there is

48 EGGS IN COLD STORAGE.

any, is into the coil room, and not into the storage
room. The perforations for outflow of air from cold
air duct, a a, are twice as numerous on bottom as on
the top, and some are placed in the face or side of
duct also. The perforations are comparatively small
holes placed quite near tog-ether, obviating- all strong-
drafts, and at the same time insuring- a very pene-
trating- circulation which will not allow of any dead
corners. The false ceiling- is perforated likewise, the
holes being- most numerous throug-h the center of
room at farthest point from cold air ducts, and more
widely separated as they approach sides of room
directly over cold air duct. If air ducts are correctly
proportioned, the perforations properly located and of
correct size, and eg-g-s are piled uniformly from side
toward center of room, the air is forced to percolate
throug-h the piles of eg-g-s where its presence has such
a salutary effect, for reasons already discussed. The
exhauster for handling- the air can be placed in almost
any location handy to power, and the air conducted to
it, but a more desirable arrang-ement is a direct con-
nected or a direct belted electric motor. Then the
fan may be placed advantageously to get direct and
shorter air ducts, saving both space in the storage
room and expense in construction.

A saving of space can be obtained by using this
tiois tern a~ system of air circulation, amounting in some cases to
fully 10 per cent of the total space cooled, and a sav-
ing of 5 per cent can be had in any house, if skill and
care are used in arranging cooling coils and air ducts.
Where rooms are moderately high the space over a
hallway or corridor may be utilized for cooling coils.
As the cooling coils are located entirely outside of the
storage room proper, the room itself can be filled
with goods snug up to the false ceiling at the top and
against air ducts on sides. The side ducts and false
ceiling only occupy about two inches of space in their
respective locations, so the space occupied by the air

EGGS IN COLD STORAGE. 49

system is very small. Storage men will at once ap-
preciate that a saving- of even 5 per cent in space adds
that much to the profits of the season's business, as
it is as expensive to cool vacant space as it is to cool it
when occupied by goods.

As an objection to the forced circulation system, g. fans
it has been urged that the expense of running fans
continuously for handling the air was so large as to
be a serious item of expense. With a well constructed
apparatus and a large light weight fan wheel running
at a slow speed, the air in a room containing 15,000
cubic feet, which will store about 5,000 cases of eggs,
may be circulated with an expenditure of effort not
exceeding one-half a horse power.

The selection of a fan for propelling the air is of
considerable moment when installing an air circulat-
ing system in a cold storage room. Fans also play an
important part in handling air for ^ventilating, and the
merits of the different kinds and forms of fans will be
discussed under "ventilation."

CHAPTER IV.

VENTILATION.

value of T N discussing- humidity and circulation, it has been

ventilation. J

1 explained how a large portion of the gases of de-
composition and impurities of various kinds, which
are incident to the presence of perishable products in
cold storage, are carried by the moisture existing- in
the air, and that when this moisture is frozen on the
cooling pipes, or absorbed by chemicals, the foul mat-
ter is largely rendered harmless. It may now be
noted further that even with a good circulation and
ample moisture absorbing capacity, there will still
be some impurities and gases, detrimental to the wel-
fare of the stored goods, which have little or no affin-
ity for the water vapor in the air, and consequently
accummulate in the storage room. Ventilation is
necessary to rid a refrigerator room of these perma-
nent gases. The introduction of a large volume of
fresh air is not essential, however, for the purpose of
purifying rooms in which eggs are stored, because
the accumulation of permanent gases in an egg room
is quite slow, comparatively (as in rooms where well
ripened fruit is stored); but a small supply of fresh
air continuously, or at regular intervals, is of much
benefit.
Ventilation by This subject of ventilation for refrigerator rooms

has been very much talked about recently, but about
which really little is known, so far as any tangible in-
formation is concerned. Some of the more progress-
ive cold storage managers have given some attention
to this part of the business, but many of the largest
and best known houses do not ventilate their rooms at
all, except perhaps during the winter or spring, when
rooms are aired out for the purpose of whitewashing.
In some cases the change of air incident to opening
and closing of doors, when goods are placed in stor-
age or removed therefrom, is relied on to supply ven-

EGGS IN COLD STORAGE. 51

Illation. This is quite inefficient, because eggs are
mostly stored during two or three months in the
spring, and removed from storage during the fall and
winter, leaving three or four months when no fresh
air of consequence can penetrate to the room, except
as the doors may be opened for the purpose of taking
the temperature of the room. Furthermore, this
kind of ventilation during the warm weather of sum-
mer and during a large part of the spring and autumn
months is worse than no ventilation at all. Some stor-
age men even take so radical a position on this matter
of opening doors during warm weather, as to insist
that the door shall not be opened for the purpose of
reading the thermometer. A double window is placed
in the door of each room, with the thermometer hang-
ing so that it can be read from the outside without
opening the door. While the writer has not practiced
this method, it seems to be a good idea, and it is cer-
tainly preferable to ventilating the room through
doors which open to the outside air. When doors
into rooms open into a corridor, the evil can be partly
prevented by piping the corridor overhead, so that
the moisture and impurities may be taken up in this
way; but opening the door or window of a storage
room directly to the outside air when the temperature
outside is materially higher will always result in
more or less bad effect on the goods, as a result of the
water vapor, in the warmer incoming air being con-
densed on same.

Another source of ventilation similar in its results
to the opening of a door or window is that resulting
from the leakage of air directly into the storage room,
through the pores and crevices in the walls around the
doors and windows, etc. — leakage of air literally — air
that gets in when everything is supposed to be closed.
The amount is usually imperceptible, but is enough
in some houses to be a serious detriment to the quality
of work done. In small houses with large outside ex-

52 EGGS IN COLD STORAGE.

posure and poor insulation this air leakage is consid-
erable, but in the big- refrigerators of several hundred
thousand cubic feet capacity, and with thorough insu-
lation, it is reduced to practically nothing. The loss
of refrigeration caused by air leakage, while of some
importance, is of small moment beside the bad effects
resulting from the moisture and impurities brought
in by the warm air from the outside. The value of
prime, tight insulation, as a conserver of refrigera-
tion, aside from a matter of keeping out the warm,
moist air, is well enough understood not to need re-
peating here, but a word about windows and doors is
properly in line with the present discussion.
use of windows Rather than consider what might be a good way

for eg-g- rooms. -"

of placing windows in a cold storage building, their
use should be discouraged. Even with four or five
separate glass, divided by air spaces, and with all
joints set in white lead, the loss of refrigeration is
large. It is also very difficult to fit insulation around
the window frame so as to make a good job; and even if
a passable job were practicable, the expense of putting
in windows is sufficient to condemn their use. The
increased fire exposure is of some consequence, too,
and with the low cost of electric light, windows should
not be thought of for cold storage work. Barring the
small amount of heat given off, the incandescent elec-
tric lamp is an ideal device for lighting cold storage
rooms, as the air is not vitiated as when using gas,
kerosene or candles.

Doors which will shut tight, forming a nearly per-
fect air seal, with a small amount of pressure, have
long been wanted for cold storage rooms. Most of the
ordinary bevel doors, either with or without packing
on the bevel, will not shut even approximately tight;
and in operation nine out of every ten stick and re-
fuse to open except after many persuasive kicks and
surges — we all know how it is. While having no in-
terest in furthering the sale of the Stevenson door,

EGGS IN COLD STORAGE. 53

which will be advertised in Ice and Refrigeration, the
writer believes it to be head and shoulders above any-
thing else in this line, and does not hesitate to recom-
mend it to those wanting- a door which will prevent
air leakage. The price is very reasonable, consider-
ing- the excellent material and fine work put into its
construction. The slig-ht additional cost over the
common door will be quickly saved, by reason of its
quick action — opening- instantly when the lever is
grasped.

Having- g-ot into the subject of air leakag-e, we may
as well see how it is caused and why it must beairleaka^e-
g-uarded ag-ainst. It is operative from the same law
as gravity air circulation, which was explained quite
thoroug-hly in the first part of the chapter on " Circu-
lation." When the outside air is warmer than that
of the storage room, the air in the storage room pro-
duces a pressure on the floor and lower part of the
room, by reason of its greater weight, and conse-
quently it seeks to escape there. If there are open-
ings near the floor where the air can flow out, and
others at the ceiling -or upper part of the room, the
air will flow in at the top and out at the bottom of the
room. Reverse the conditions of temperature, and
the direction of flow of air is also reversed. That is,
when the air outside is colder than the air of the
room, the cold air will flow into the room at the bot-
tom and the comparatively warm air of the room out
at the top. This action is nicely illustrated by not-
ing the air currents in a door which is opened into a
cold room when the temperature is very warm out-
side. The warm air rushes in at the top of door and
the cold air of room out at the bottom. In cold
weather the direction of air flow will be reversed.

Perfect inclosing walls for a cold storage room
would be perfectly air tight, as they would be if lined stora^e
with sheet metal, with soldered joints. The interior
conditions would then be under more perfect control.

54 EGGS IN COLD STORAGE.

It is hardly necessary to do this (although it has
been done in case of some old time houses), as a
practically tight job may be had by using- the right
materials, well put on. Air leakage may not be ex-
actly ventilation, but it is a kind of ventilation which
has given the writer some trouble in the past, and
does still, consequently the difficulties of operating
a house with defective insulation and large outside
exposure, and still turn out first-class eggs, are very
thoroughly appreciated.

4JnfmruItebela' Methods of ventilation which are permissible
when applied to the work of supplying fresh air to
ordinary structures are generally dangerous when
used to ventilate cold storage rooms. The problem
in ventilating non-insulated structures is merely the
supplying of fresh air from the outside without caus-
ing a marked change in the temperature, and without
creating strong drafts. Air for the ventilation of
refrigerator rooms, during warm weather, must be
of very nearly the same temperature and relative
humidity as the air of the room to be ventilated, and
free from the germs which hasten decay and cause a
growth of fungus on the products in storage. If a
door or window of a storage room is opened directly
to the outside atmosphere, there will be little or no
circulation of air into and out of the room when the
temperature outside and in is about the same, unless
the wind should be favorable. As we cannot ventilate
in this way when the air outside is colder than the
storage room, on account of freezing the eggs, and the
introduction of fresh air, which is warmer than the
storage room, is not permissible, for reasons already
given, the matter reduces itself to not ventilating at
all during warm weather (which most houses prac-
tice), or of properly cooling and purifying the air be-
fore forcing it into the storage room. It will bear
repeating that it is positively bad practice to allow air
from the outside to get into an egg room during the

EGGS IN COLD STORAGE. 55

summer months, also during* a large portion of the
spring- and fall months, unless cooled and purified
first. The fact that we cannot see the moisture de-
posited in the form of beads of water, or floating- in
the air in the form of fog- or mist, does not indicate
that it is not present. The sling- psychrometer, de-
scribed in discussing- humidity, will give an accurate
indication of the result of this unscientific method of
ventilating-.

Any natural means of handling- air for ventilation *°}Jf Bri**s
is inaccurate and inoperative, or it may be positively ventllatlon-
harmful, except under favorable conditions. If de-
pending- on natural gravity for ventilation it will be
g-uesswork, to a greater or less extent, because de-
pending on conditions which vary with the season,
temperature, direction and force of the wind, etc.
The late Robert Brig-g-s, an authority on ventilation,
makes a concise statement of the advantages of using
fans for ventilation, in his " Notes on Ventilating and
Heating."* He says: "It will not be attempted at
this time to argue fully the advantages of the method
of supplying air for ventilation by impulse through
mechanical means — the superiority of forced ventila-
tion, as it is called. This mooted question will be
found to have been discussed, argued and combated
on all sides in numerous publications, but the con-
clusion of all is, that if air is wanted in any particular
place, at any particular time, it must be put there,
not allowed to go. Other methods will give results
at certain times or seasons, or under certain con-
ditions. One method will work perfectly with certain
differences of internal and external temperature,
while another method succeeds only when other
differences exist. . . . No other method than
that of impelling air by direct means, with a fan, is
equally independent of accidental natural conditions,
equally efficient for a desired result, or equally

* Proc. Am. Soc. Civil Engineers, May, 1881.

KGGS IN COLD STORAGE.

Plenum vs.
vacuum
method of
ventilation.

Advantages of
the plenum
or pressure
method.

controllable to suit the demands of those who are
ventilating-."

There are two general methods, with some modifi-
cations, for handling- air for ventilation: The plenum
or pressure method, in which the fresh air is forced
into the room ; and the vacuum or exhaust method, in
which the foul air is drawn out. The exhaust method
is to be avoided for ventilating- cold storag-e rooms,
for reasons which we shall see presently. With this
method, sometimes the exhaust steam from an engine
is utilized to induce a draft of air upward from storag-e
room, by heating- the air in a stack or ventilation flue
connected at its lower end with the room to be ven-
tilated. In some cases no provision is made for an in-
flow of fresh air, in which case it will seep in at every
crack, crevice and pore (by reason of the partial
vacuum created by exhausting- the foul air out), bring-
ing- a load of moisture and g-erms of disintegration
into the storag-e room. This exhaust steam method
is no different in its result than if a fan were placed
so as to draw the air out of the storag-e room under
conditions which are otherwise the same as described
in connection with the exhaust steam method. Should
we provide an inlet for fresh air, throug-h proper ab-
sorbents, the same law would be operative, only to a
lesser degree, as a partial vacuum must, in any case,
be created before the air from outside would flow into
the room, tending- to the dang-erous air leakag-e already
fully discussed.

The plenum or pressure method is by far the best
for our purpose. The air should be forced into the
room by a fan, after first properly cooling-, drying
and purifying- it. An outlet for the escape of the foul
gases which it is desired to be rid of, should be pro-
vided near the floor, as these gases, by reason of
their greater gravity, tend to accumulate in the lower
part of the room. It will be observed that forcing
the fresh air in creates a pressure inside the room,

EGGS IN COLD STORAGE. 57

and if there is any air leakage, it will be outwardly
from the room — exactly the way we want it to go.
Having- brought our subject to the point where it is
found that the best way to ventilate is by the use of
fans forcing- the air into the storag-e room, we will
determine what type of fan is best adapted to our
needs. What is said of fans for ventilation is equally
true if they are to be used for forced air circulation,
described under head of circulation.

It is admitted by a majority of experts on air mov- ™
ing- machinery that the disk or propeller wheel ty pe type of fan-
of fan, throug-h which the air moves parallel to the
axis of fan, is not efficient or desirable for work where
the air has to travel throug-h a series of tortuous air
ducts, as in the forced air circulation system for cold
storag-e work, or for ventilation purposes where there
is some resistance. Where any resistance of import-
ance is encountered, the disk fanjnust be driven at a
hig-h rate of speed, and at an immense loss of power, to
compel it to deliver its full quota of air. Another dis-
advantage of the disk type is the difficulty of belting
to the shaft, or of g-etting- power to the fan in any
form, if it is inclosed entirely in an air duct. The disk
type will therefore be dismissed, and the well known
centrifug-al, or peripheral discharg-e fan taken up.

This type of fan draws the air in at its center Advantages of

J r the centrifugal

parallel to the shaft, and delivers it at rig-ht ang-les
the shaft at the periphery or rim of the fan wheel,
the law g-overning- its action being- the well under-
stood centrifug-al force, which is commonly illustrated
when we see the mud fly from a bug-g-y wheel or the
water off a grindstone. The advantag-e of these fans
over the disk type is that the centrifugal action set
up by the rotary motion of the fan is utilized to give
velocity to the air in its passage over the fan blades.
In the selection of a fan for the purpose of forced cir-
culation in the storage room, or for forcing in fresh
air for ventilation, it should be noted that a large slow

58 EGGS IN COLD STORAGE.

running- fan wheel is very much more economical of
dtffertntspeaeds power than a small fan running- at a hig-h rate of speed,
both doing- the same amount of work. The loss of
ref rig-eration, too, in a rapidly moving- fan, is of conse-
quence, because the air is warmed by impact with the
blades. The proportion of power saved by the use of
a larg-e fan running- at a slow rate of speed, rather than
a small fan running- at a hig-h rate of speed, both de-
livering- the same amount of air, is almost phenomenal,
and does not seem at all reasonable at first view. The
volume of air delivered by a fan varies very nearly as
the speed, while the power required varies about as
the cube of the speed. That is, doubling- the speed
doubles the volume of air, while the power required is
increased eig-ht times. We will take a specific case.
A 45-inch fan wheel, revolving- at a speed of 200 revo-
lutions per minute, delivers, say, 5, 000 cubic feet of air
per minute, and requires but one-quarter of a horse
power to operate it. If the speed is increased to 400
revolutions, the volume of air delivered will be only
about 10,000 cubic feet, while the power required to
drive it will be raised to two horse power. These
fig-ures are theoretical, but within certain limits are
approximated in practice.
LOSS of power por use [n coid storage work the objection com-

from excessive ° J

fan weights. mon to nearly all the air moving- machinery found
listed by the manufacturers is the seemingly unnec-
essary amount of metal used in its construction.
The heavy weig-ht of the fan wheels, and the larg-e
diameter of shaft necessitated by such weig-ht, causes
much friction on the journals, so that when running-
at the slow speeds desirable for cold storag-e work,
more power is required to overcome the mechanical
friction than is actually required to move the air.*

*Having been unable to find a fan wheel well suited to the requirements of
cold storage duty, the writer has designed and constructed a line of fan wheels
especially for slow speeds, which are amply strong and capable of moderately
high speeds, when necessary, but are very much lighter than most fans on the
market, and consume proportionately less power in mechanical friction.

EGGS IN COLD STORAGE. 59

No doubt the high speeds necessary for some work
have obliged the manufacturers to make their fans
amply strong- for the highest speeds, consequently
they are not economical for the slower speeds. It
would not be appropriate for a person to fan himself
with a dinner plate — it would do the work, but would
not be economical of power.

So far we have found out what kind of ventilation
is not desirable, and have an inkling- of what kind
would be desirable. The question before us now is to
properly treat the air before introducing- it into the
storag-e room, so that it may be fresh — /. <?., pure
oxyg-en and nitrog-en, without excessive moisture,
and free from the impurities and germs which may
contaminate the product which is being- refrig-erated.

The questions referring- to temperature contained Questions
in the letter of inquiry sent out by the writer before ventilation.
beg-inning- to write these articles are as follows :

First. — What plan do you pursue in ventilating
egg rooms?

Second. — Under what circumstances and how often
do you ventilate?

Third. — How often do you consider it advisable to
make a complete change of air?

Outside of a bare dozen, the replies on this much- Miscellaneous

replies to ven-

talked-of subject were of no value whatever for our tiiation queries
purpose. Most of those answering- do not ventilate ;
many others get their ventilation through the opening
of doors; some ventilate through an elevator shaft, by
opening doors at top and bottom, etc. Only three or
four are properly cooling and drying the air before in-
troducing it into the egg rooms. One successful stor-
age manager says that. "It is trouble enough to take
microbes, bacteria, moisture, etc., out of one batch of
air" (meaning the air in his rooms at the beginning
of the season), without adding to his troubles by send-
ing in more air loaded down with the same mischief
makers. As before pointed out, unless the air to be

60 EGGS IN COLD STORAGE.

used for purifying- the rooms is itself first cooled and
purified, this man's idea is perfectly correct.
impurities ex- The free outside air during- warm weather, espe-

isting-inthe . ...

free outside air. cially in the vicinity of our large cities, contains,
among- many others, g-erms which produce the para-
sitic plant growth which is called mildew or mold. The
exhalation from the lung-s of the many animals and
men who inhabit our cities, and the evaporation
from the dust, dirt and decaying matter of various
kinds peculiar to the street, render the air a recep-
tacle and conveyor for impurities and germs of many
species. The species of germs which concern us are
active in proportion to the temperature and humidity
of the air. In a warm atmosphere which contains
much moisture they take root and grow rapidly,
throwing off more germs of their kind, which impreg-
nate the air in an increasing ratio as the humidity and
temperature are increased. The humidity of the
outside air is not necessarily increased with the tem-
perature, but it is always increased to some extent,
and as the temperature of the outside air rises we
must necessarily be more and more careful how we
treat and handle the air which we are to use for the
ventilation of refrigerator rooms.

^ *s rea-^^y understood why it is necessary to cool
the air before introducing it into the storage room to
at least as low a temperature as that of the room to
be ventilated, and some cold storage managers have
ventilated on this basis, thinking that this was all
that was necessary for successful ventilation. Air
cooled only to the. temperature of the storage room
will be saturated with moisture at that temperature,
and will be in condition to develop mold rapidly. An
improvement on this manner of handling is to cool
the air to be used for ventilation to a few degrees (say
five or six) below the temperature of the storage
room. The air will then be rendered as dry as that of
the storage room. This is a good method of ventila-

EGGS IN COLD STORAGE. 61

tion, and one which the writer has practiced, but it is
open to criticism, because of the fact that the air is
not purified fully at the same time it is cooled and
dried. If the air is first cooled to several degrees
below the temperature of the room to be ventilated,
it will be of benefit to the room, if not overdone, but
in results will not be equal to a system to be described
and illustrated further on in this article.

Several houses known to the writer ventilate by inefficient
letting the warm outside air in at a high point of the
ceiling, directly over cooling coils, expecting that the
air will be properly cooled and dried before it flows
into the room itself. The same objections are appli-
cable to this system as are applicable to any plan of
ventilating where the air is cooled only to the tem-
perature of the room to be ventilated, because the
air will be at the saturation point, and will therefore
raise the humidity of the room, as well as introduce a
quantity of germs and impurities.

If we ventilate by simply cooling the air, the simPle air

of . cooler.

simplest and most effective method, as shown in
Fig. 9, is to take the air from as high and sheltered a
place as is accessible about the building; draw it
down over frozen surfaces in the form of brine or
ammonia pipes, which may be arranged anywhere
along the wall of a room, outside of the storage en-
tirely, if more convenient. An exhaust fan takes the
air from the coils in the ventilating flue and forces it
into the room to be ventilated, allowing it to escape in
the neighborhood of the cooling coils, where it will
mix with the air circulation, and flow into the room
through the regular channel. It is necessary to pro-
vide an outlet for the escape of foul air whenever
fresh air is forced into the room. This outlet should
be near the floor, and of about the same area as the
inlet pipe. A steam coil may be provided beneath
the cooling coil in ventilating flue, as shown in the
sketch, for the purpose of melting the frost off the

EGGS IN COLD STOKAGK.

I3RIMEOR

AMMONIA
COIL,

Coi u

FIG. 9.

pipes. The casing around the cooling coil should, of
course, be insulated moderately, as well as the pipe

EGGS IN COLD STORAGE. 63

leading- from it to the storage room, wherever exposed
to the warm outside air. The size of apparatus
necessary for this purpose need not be large, as the
quantity of air necessary for ventilating egg rooms is
quite small, comparatively.

"Americus" mentions a method of washing air
ventilation, in the July, 1898, number of Ice and Re-
frigeration, which seems to have advantages. The
idea is to draw or force air through a body of water
or brine by immersing the intake pipe so that the air
will bubble up through the liquid. This seems quite
simple, but when it comes to forcing air through a
liquid with a fan it is not so simple, as nothing short
of an air pump will drive air through a pipe submerged
as above described, unless the opening from pipe is
placed quite near the surface of the liquid; in which
case the benefit to the air is very small. Experiments
conducted by the writer along this line were consid-
ered failures.

Shown in Fig. 10 is what appears as a rather com-
plicated apparatus, but on investigation it proves to
be quite simple. There are three members to this
system, as follows: First, The air washing tank, in
which the air flows upward against a rain of water
from a perforated diaphragm above, as clearly shown
in the sketch. This not only cools the air to the tem-
perature of the water, say 55° F. or 60° F., but it also
takes out a large portion of the impurities of various
kinds. From the washing tank the air is passed on,
in a comparatively pure and cool state to be still fur-
ther cooled. Second, The cooling tank, in which the
air is cooled to several degrees lower temperature
than that of the storage room. This removes the
moisture which holds in suspension the few impuri-
ties which may have passed the washing tank, the
moisture being deposited on the frozen surfaces
within the cooler. From the cooler the air is passed
into, third, the drying box, which contains chloride of

EGGS IN COLD STORAGE.

EGGS IN COLD STORAGE. 65

calcium. This chemical is a well known absorber
of moisture, what is technically known as a deliques-
cent substance. If moisture of any account passes
the cooler it is surely stopped in the dryer, which
" makes assurance doubly sure," so far as delivering
a pure, dry air is concerned. The "microbes, bac-
teria, moisture, etc." (which influenced the gentle-
man mentioned previously not to ventilate), are ef-
fectually disposed of by this method. It would be a
hardy germ, indeed, that would not succumb to such
vigorous treatment.

The volume of air necessary for ventilating- a
given size of egg room can only be estimated, and
probably no two storage men will agree as to what is
a correct quantity. Some say that the introduction
of a volume of air equal to that of the room to be
ventilated should take place each day; others twice
each day; some even take so radical a view of it as to
say the oftener the better if the air is properly dried
and cooled. This is of course true enough, but the
foul gases which we can be rid of by ventilation ac-
cumulate but slowly in an egg room, and it is probable
that the introduction of a volume of fresh air, properly
treated, equaling that of the egg room, twice each
week will be ample for the purpose of keeping the
room in good condition, and in most cases once each
week may do nearly as well. There is much to be
developed yet in the direction of ventilation of refrig-
erator rooms, more particularly in the way of some
method of knowing when a room requires ventilating.
Perhaps Prof. Siebel or some equally bright chemist
may be able to assist us on this point by informing us
what the gases are which we must dispose of, and
indicate some simple method of determining their
presence, and in what proportion.

All that has been said about ventilation so far
applies only to the ventilation of cold storage rooms
when the air without is warmer than the air of the

66 EGGS IN COLD STORAGE.

storage room. We will now give our attention to
another kind of ventilation, that is applicable when
the air without is at about the same temperature as
the storage room, or at some degree lower. This
will be designated as cold weather ventilation, as this
term seems to express its function perfectly.
SiadstoraCe in -^ ^as ^onS been a well understood fact that eggs
cooi weather. an(j other products held at about the same or a higher
temperature take more harm in cold storage during
the cool or cold weather of fall and winter than during
a long- carry throug-h the heated term. Much has
been said and written about why the old style over-
head ice cold storag-es g"ive such poor results during
fall and winter, the reason assig-ned being- lack of
circulation, as the meltag-e of ice ceases when the
cool weather comes. This is true; further, the large
body of ice becomes an evaporating- surface, and the
dirt and impurities which are found in all natural ice,
to a greater or less extent, have accumulated on the
top of this ice, and the evaporation which takes place
carries gases from this miscellaneous matter into the
air of the storage room, with consequent bad results.
In some houses this may be avoided by closing the
trap doors covering circulation flues, but it is seldom
done, and in many houses it is impossible.
Pipe cooled Now are we who cool our storage rooms with brine

rooms in . .

cold weather. Or ammonia pipes very much better off in this one re-
spect than those who have these much despised over-
head ice cold storages? Our rooms are cooled by
frozen surfaces, on which accumulates the evaporation
from the goods in store, which, as we have already
plainly seen, contains much foul matter and impurities.
Precisely as in the ice cold storages, the cooling sur-
faces, which absorb moisture during warm weather,
become evaporating surfaces, and give back to the air
of the room a considerable portion of the various im-
purities and germs which have been accumulated dur-
ing the warm weather of summer. To make this point

EGGS IN COLD STORAGE. 67

more plain it may be considered thus: During- the
period when the outside air is considerably warmer
than the air of the storage room it is necessary to keep
some refrigerant at work cooling- the air within. This
is usually done by circulating- brine or ammonia
throug-h pipes, and the air of the room is circulated in
contact with the pipes. When the outside tem-
perature is hig-h, more of the refrig-erant must be
circulated, or its temperature must be lowered;
as the weather turns cooler in the fall, less re-
frigerant, or the same amount at a higher temper-
ature, must be circulated, and when the air with-
out reaches the temperature of the room, the
circulation of refrigerant must be discontinued al-
together. When this is done the moisture on the
cooling pipes begins to evaporate. This evaporation
added to that which is given off by the eggs them-
selves soon renders the air saturated with very im-
pure and poisonous vapors, which cause the eggs to
deteriorate very rapidly.

The influence which the temperature of the refrig- influence of

& temperature of

erant flowing in the cooling pipes has on the condition refrigerant in

cooling- pipes.

of a storage room may be better understood by tak-
ing a specific case: A room with a temperature of
33° F. and a humidity of 70 per cent has a dew point
(temperature at which the air precipitates moisture)
of 25° F. Therefore any cold surface (as a pipe sur-
face), having a temperature of 25° F. or lower, will
attract moisture when exposed to the air of the room.
If the pipe surfaces are heavily coated with frost, as
they usually are as cold weather approaches, the frost
acts as an insulator, and the refrigerant flowing in
pipes must be at a considerably lower temperature
than the air of the room, or no moisture is attracted.
We have all noted how the accumulation of moisture
on pipe coils is slower and slower as the thickness in-
creases, until finally a limit is reached where no more
frost will form; yet owing to the largely increased

68 EGGS IN COLD STORAGE.

surface the room can be kept at its normal tempera-
ture. If pipes are badly loaded with frost, sometimes
no absorption of moisture will take place when the
refrigerant flowing' in the coils is 10° or 15° below the
temperature of the room. The surface exposed to
the air of the room, whether in the form of frost or
otherwise, must beat or below the temperature of the
dew point, or no moisture will be absorbed. The
value of suitable moisture absorbing- surfaces as the
cool weather of fall and winter approaches cannot be
overestimated, as many have found to their sorrow
that two weeks' stay in cold storag-e under bad condi-
tions in cold weather will do more harm to the eggs
than four months during- hot weather.

The remedy for this trouble is found in keeping
the air of the room from coming- in contact with the
poisonous frost which has been accumulated on the
pipes during- their period of duty during- warm
weather; or what is still a better way is to not allow
the frost, to accumulate on the pipes at all, by using- a
device, described further on under head of absorb-
ents. How to keep the air from contact with the frost
on pipes is not an easy matter, and in case of piping-
suspended directly in the room it is an impossi-
bility.
Evaporation With a system of screens arranged around coils,

from frost J

accumulated on as described in the first part of the paper on circula-

cooling- pipes. L

tion, trap doors may be fitted to the opening's and the
air circulation shut off in this way; but the simplest
and best way is to equip the rooms with forced cir-
culation, and locate the pipes outside of the room en-
tirely. Then it is only a matter of shutting- off the
circulation over coils, allowing- it to continue throug-h
a by-pass, or if the device shortly to be described is
used, the circulation may be allowed to continue over
coils. It seems quite clear, from what has been writ-
ten, why a storage room gets foul quickly during cool
weather, and also that the bad conditions. may be bet-

EGGS IN COLD STORAGE. 69

tered by cold weather ventilation. The harm result-
ing- from the foul evaporation from frost on cooling-
pipes may be obviated by not allowing- contact between
it and the air of room, but the evaporation from the
eg-g-s themselves must be taken up by other means
when cooling- surfaces are no long-er operative.

By carefully observing- conditions a storag-e room
mav nearly always be kept in prime condition during- ventilation,
cold weather by no other means than the introduction
of fresh outside air at as frequent intervals as rig-ht
conditions of temperature and humidity will permit.
It is quite safe to force in plenty of air which has
about the same temperature and humidity as the
room to be ventilated. There are few impurities in
the clear, crisp air of a brig-ht fall day, and many such
are available for our purpose in the latitude of Min-
nesota and New York, and a somewhat smaller num-
ber, perhaps, in the latitude of Iowa or Ohio. It is only
a matter of handling- the free air of heaven under-
standing-ly. One's impressions, however, will hardly
do in judging- what air is g-ood to use for ventilating-
purposes. If you have a brig-lit, clear day, or, what is
still better, a clear, cold nig-ht, which has the appear-
ance of being- what you want, g-et out your sling-
psychrometer and set all g-uesswork aside. It is
frequently possible to fill your eg-g- rooms with fine,
pure air at a temperature about the same as that of
the room, as early as the latter part of October, if
you are watching1 for the-opportunity. Provide a g-ood
big" fan wheel, which will handle a larg-e volume of air
in a short time, and when conditions are rig-ht blow
your rooms full of it. Repeat this whenever the
weather conditions will permit.

We may now consider cold weather ventilation
under another condition, viz.: When it is colder out- weather-
side than inside the storage room. Whenever the out-
side air is 8C or 10° below that of the storag-e room it
is always perfectly safe to introduce it into the stor-

70 KGGS IN COLD STORAGK.

age room, after it has been first warmed to the tem-
perature of the room to be ventilated. That is, it is
safe so far as introducing- moisture or impurities is
concerned. If we should ventilate in this way con-
tinuously our humidity would be lowered to a point
where the eggs might suffer from evaporation. It is
necessary, therefore, that observation of the humidity
of the room so ventilated be taken, so that this kind
of ventilation may not be overdone.
Manner of in- The method of getting- air into the rooms under

troducmg- air. &

these last two systems of ventilation is of no special
moment, except that it be under control, and we have
already noted that the only good way of handling- air
wras by the use of fans, preferably large and of light
weight, and running at a slow speed. Where the
forced circulation is installed, it is sometimes practi-
cable to so connect the fans used for this purpose,
that cold weather ventilation may be handled by them;
but a separate fan is much better, and while seeming
more complicated is really simpler to operate, because
handled independently. When using an independent
fan or when using the forced circulation fan for ven-
tilating, the fresh air mixes with the circulation and
is well distributed by it to various parts of the room.
The ventilation of cold storage rooms is not a
matter which can be safely left to such help as may
be at hand, and if good results are to be secured " the
boss" should see to it himself. Cold weather venti-
lation, especially, must be handled scientifically or
trouble may result instead of benefit. No absolute
rules can be given for handling ventilation because of
widely varying conditions, but if what has been writ-
ten is read and studied carefully the subject can be
taken up intelligently and followed out to its legiti-
mate conclusion.

CHAPTER V.

ABSORBENTS.

HE use of absorbents in cold storage rooms has Purifying air

Toy absorbents.

been common since the industry was in its in-
fancy; their use originating-, no doubt, from an appre-
ciation of the fact that the air of a storage room
quickly became too moist and impure to do the work
of preservation perfectly. When absorbents and ven-
tilation are applied to refrigerator rooms they prac-
tically have one duty in common — that of purifying
the air. Ventilation purifies by furnishing pure air
which displaces the foul air; absorbents by attracting
the moisture, and with it the impurities of the storage
room ; but where ventilation is largely for the purpose
of forcing out the permanent gases or impurities
which have little affinity for moisture, absorbents are
for the purpose of taking up the moisture and the
germs and impurities which are absorbed by it.

Active absorbents can be made to perform duty in Prof. Nice's

. . . . . . .... system which

absorbing the moisture which is usually condensed on utilizes an

. absorbent.

the cooling coils, as illustrated in one style of the
antiquated overhead ice cold storages. If the writer
remembers correctly, the system is called Prof.
Nice's system. In this system the ice is supported
above a water tight sheet iron floor which forms the
ceiling of the storage room, the air of the room being
cooled merely by contact with this cold metal surface,
which is cooled by the ice above. The moisture
given off by the eggs in storage, and that resulting
from air leakage was taken up by an absorbent,
chloride of calcium being the chemical mostly in
use for this purpose. It was applied by suspend-
ing it in pans at the ceiling of the room, or in
some cases on the floor under the goods. Prof.
Nice's system gave good results years ago in com-
petition with the Jackson, Dexter, McCrea, Stevens,
etc., systems of overhead ice cold storage, which low

EGGS IN COLD STORAGE.

Queries
relating- to
absorbents.

Whitewash a
good wall
coating-.

temperatures, and the improved systems of air cir-
culation now in use have rendered obsolete to a greater
or less extent. Mention is made of this system, not
as recommending- it, but to show the possibilities of
absorbents in drying- and purifying- egg rooms.

The letter of inquiry sent out by the writer con-
tained three questions referring to absorbents, writ-
ten with an idea of ascertaining- the coating- used for
the walls of a storag-e to the greatest extent; what ab-
sorbent was the favorite, and in what manner applied.
The questions are as follows :

I. Do you use an absorbent or purifier in your
egg rooms?

II. In what way do you use or apply them?

III. Do you paint or whitewash? What kind and
how often applied ?

The most common wall coating in use for egg
rooms is plain every-day whitewash, in various pro-
portions of lime and salt. Several recommend one
part of lime and one of salt. This makes a very
good whitewash, giving a firm, hard surface, but un-
less some method of blowing warm, dry air through
the rooms is feasible, it will dry very slowly, which
is likely to cause it to have a mottled appearance
instead of the pure white which gives a storage room
such an attractive appearance. A better proportion
for ordinary cold storage work is two parts of lime
and one of salt. This mixture will dry faster, and
will give a white surface which will not easily rub or
flake off. There are many formulas for good white-
wash, some of them so complicated as to be impracti-
cable; but plain lime and salt, with perhaps the addi-
tion of a little Portland cement, will be good enough
for our purpose.

This last formula would then be six parts white
lime, three parts salt, one part Portland cement. In
preparing this wash, proceed as follows: Slake the
quicklime by pouring on boiling water, stirring

EGGS IN COLD STORAGE. 73

thoroughly during- the process. A half bushel ofThebest

formula for

lime is all that can be handled easily. Pour on only whitewash.
a little water at first, adding- more as the mixture
thickens, and do not allow the lime to become dry, or
it will "burn" and become lumpy. When the lime is
thoroug-hly slaked and reduced to the consistency of
cream, add the salt while the mixture is still hot — the
salt will dissolve better — adding- more water as is
necessary to keep it to the proper consistency. The
Portland cement should be added only to each pail-
ful as used, as it sets if allowed to stand, and does
not retain its tenacity. A good sized handful to each
pailful of the wash is about rig-ht. By the addition of
a teaspoonful of ultramarine blue to each pailful, the
brown effect resulting- from the addition of the cement
will be neutralized.

Storag-e rooms should be whitewashed during- whitewashing-

0 storage rooms.

cool, dry weather, with the doors- open, or warm, dry
air from a steam coil should be circulated throug-h
the room. This is quite a simple matter where a
house is equipped with forced circulation. Cover the
walls, ceiling- and floor with a coat of whitewash
each spring-, and allow ample time for the rooms to
air and dry out before goods are placed in them. If
whitewash is to have a nice white appearance it must
not be too long- in drying-; on the other hand, if dried
too quickly it will flake or cleave off more readily.
The quickest method of applying whitewash is with
a compressed air spray. It will make a fair job, and
is done much quicker than by hand.

The cold water paints, which are now quite com- cold water

j . r paint.

mon under various names, are good for many places
where whitewash will not do, as on doors and in the
corridors, or wherever the clothing- may come in con-
tact with the woodwork, or where a product is handled
which may be injured by the flaking off of whitewash.
Whitewash will generally rub or flake off to some
extent, but the best of these cold water paints are

EGGS IN COLD STORAGE.

Shellac for
wall coating.

Lime as an

absorbent of
moisture and
impurities.

nearly as impervious as so much oil paint, and quite
valuable for nearly all interior and some exterior
work. Many houses use nothing else for their refrig-
erator rooms, but the expense is not warranted, as
whitewash will do equally well in most places. It is
a good idea to keep some of this cold water paint on
hand, and apply it at intervals to doors, etc., when
they become soiled by handling. This is much better
than to paint doors some dark color so they will not
show soil — nothing compares with a pure white — and
oil paint has no place about a storage room.

Shellac is an old stand-by finish for refrigerator
rooms, and if selected ceiling is used, it makes a very
neat piece of work, as it brings out the natural grain
of the wood, than which there is no more beautiful
finish. The surface scratches easily and will look
mussy unless renewed frequently, but there is no
serious objection to shellac (barring the expense), as
it is strictly odorless and wraterproof. It has no puri-
fying or disinfectant properties like lime and salt
whitewash, in appearance is very little superior, and
the much increased expense makes it very little used
at present. Many other preparations are in use
under various names, but whitewash is as good as any
of them, with the exception previously noted.

The two chemical absorbents in general use for
taking up moisture and the impurities from cold
storage rooms are chloride of calcium and lime
(either unslaked or air slaked, or in the form of
whitewash, as before mentioned.) Occasionally
waste bittern from salt works is used, but the active
principle of bittern is chloride of calcium. Ordinary
quicklime has the property of absorbing moisture and
impure gases from the air, and is used in very much
the same way as chloride of calcium; that is, it is
placed around the room on trays or pans. Lime,
however, has very little capacity for moisture as com-
pared with chloride of calcium, and when exposed to

EGGS IN COLD STORAGE. 75

the air it will simply air slake, which means that it
will absorb moisture enough from the air to disinte-
grate into the form of a powder. Lime in this form is
known as air slaked lime, and is used to a large ex-
tent in egg- rooms. Air slaked lime as it comes from
the lime house will absorb very little moisture, but it
gives off minute particles of lime which have a good
effect in preventing the growth of fungus, which we
have already fully discussed. Air slaked lime is
usually applied by spreading on the floor of the room,
between the 2X4's (which are used at the bottom of
each pile of eggs), to the depth of an inch or more.
This must necessarily be done when the eggs are
piled, and consequently its efficiency is very low
when the cool weather of fall comes. This defect
has, been overcome by scattering fresh air slaked
lime through the rooms so as to create a cloud of lime
dust, but this is objected to because it musses up the
cases. A better way of using lime is in the lump
form — quicklime — which can be placed around the top
of the room in trays or pans and renewed from time
to time through the season.

Chloride of calcium is the most vigorous absorb-
ent (or drier, as it is called) which we are discussing. absorbent-
It is the same salt of the metal calcium as common
salt (chloride of sodium) is of the metal sodium. Both
have a strong affinity for water, but chloride of cal-
cium is much the more energetic of the two. Where,
in a moist air, common salt simply attracts enough
moisture to become damp, chloride of calcium will
absorb enough water to lose its solid form entirely,
uniting with-the moisture of the air to form a solution
or brine. The strong affinity of this salt for water
has been utilized for the purpose of drying and puri-
fying refrigerator rooms, and in this capacity has
been a general favorite for years. The most primi-
tive method of applying it is to place it in a simple
iron pan, allowing the brine to run off into a pail as

76 EGGS IN COLD STORAGE.

fast as formed. A better way is to support the cal-
cium on a screen of galvanized wire, with a galvanized
pan below for catching- the brine. This allows of a
free circulation of air around the calcium. This
apparatus should be suspended near the ceiling of the
room, one end slightly higher, to allow the brine to
run off into a galvanized iron pail, supported at the low
end of the pan. Galvanized iron is specified because
black iron rusts badly when exposed to the air.

^ st^ better way of applying chloride of calcium,
~ wni°n makes the calcium do two separate and distinct
duties, is a method recently designed by the writer.
It has proven itself especially valuable for use in
rooms where the air is circulated by mechanical
means, and in which the air is cooled by passing over
brine pipes, through which the brine is circulating at
a comparatively high temperature. If low brine tem-
peratures are used in combination with the device
about to be described, the tendency may be to dry the
air to such an extent as to be detrimental, and ample
pipe surface must be provided and the quantity of
brine flowing through pipes reduced so that no ex-
cessive drying effect will take place. The device
consists simply of supporting a quantity of chloride
of calcium above the cooling coils, so that the brine,
resulting from the absorption of moisture by the cal-
cium, will trickle down over the pipes. This effect-
ually prevents any formation of frost on the pipes,
and therefore keeps them at their maximum efficiency
at all times. The air, in passing over the brine
moistened surface of the coils is purified, and as the
brine, after falling to the floor of the coil room, goes
to the sewer, no contamination can take place.

Do not in any method of using chloride of calcium
evaporate the water from the brine and use the salt
over again. The impurities will stay in the salt
to a large extent, which is quite harmful, and the
calcium has at least lost its value as a purifier, to a

EGGS IN COLD STORAGE. 77

large extent. The quantity of calcium necessary Quantity of

j ,, ,.,. . - , . , ., . , J chloride of cal-

depends on the conditions under which it is to becium necessary,

used, but in any case it is safe to use much more than

the writer saw in use in an eastern house recently.

A room about 30X50 and about fourteen feet high

had the refrigerant shut off, and the room was in

rather bad condition as to moisture, etc. In each end

of the room a pail was placed, on which rested a wire

screen, with perhaps ten or fifteen pounds of chloride

of calcium on it. Electric fans were playing on the

calcium, which was doing its best, but it seemed

"like trying to dip the sea dry with a clam shell."

This room should have had at least two drums (about

1,200 pounds) at work in it to do it justice.

CHAPTER VI.

Experiments
proving1 that
eggs must
evaporate.

PACKAGK.

EGGS are continually giving- off moisture from
the time they are first dropped by the hen until
they disintegrate, unless sealed from contact with the
air, and we can therefore never hope to keep them in
cold storage for several months without their losing
some weight by evaporation. To prove that eggs
must evaporate, the following experiment was tried
by the writer in his early experience: An ordinary
30-dozen egg case was lined with tin, with all joints
carefully soldered. The eggs were then placed in
the fillers in the tin lined case in the usual way, and
an air tight tin cover soldered on, forming a hermeti-
cally sealed package. After about sixty days' stay
in an ordinary refrigerator the tins were unsoldered.
The result noted was peculiar and startling. The
inside of the tins was dripping wet, and very foul
smelling, and the eggs were all rotten. This same
experiment-was tried by a friend, working independ-
ently and without knowledge of the writer's experi-
ment. He used an ordinary fruit jar, with screw top
fitting onto a rubber ring. His results were similar.
In addition this gentleman packed some eggs in flour
in a fruit jar, otherwise under the same conditions
as the other experiment. The eggs packed in this way
were all found to be in good condition when the jar
was opened, as the moist evaporation from the eggs
had been taken up by the flour. These experiments
prove beyond a doubt that an egg must evaporate
continually, and they prove further that the eggs
must be surrounded by some medium which will
absorb this evaporation.

We have noted in the chapter on "Circulation,"
how the air is best circulated so as to remove the

EGGS IN COLD STORAGE. 79

moisture and impure gases from the vicinity of the
eggs. This must be done, otherwise the fillers and
package containing- the eggs would shortly be in as
bad condition as the fillers in the experiment just
mentioned. The theory and explanation of the other
conditions in the storage room necessary for success-
ful egg- refrig-eration have also been taken up under
the various heads. We will now look into the require-
ments of the packag-e containing the eggs while in
cold storage.

The questions contained in the letter of inquirvQueries

J relating- to

relating to the egg package are as follows: package.

1. What egg package have you found to turn out
the sweetest eggs?

2. Have you used any kind of ventilated egg case,
and with what results?

3. Have you ever used open trays or racks, and
with what results?

As many different people have experimented with various woods

. m use for cases.

different packages, hoping to get something which
would turn out perfectly sweet eggs, with little evap-
oration, the replies received to the questions relating
to packages are interesting, and many contained in-
formation valuable as data. The favorite package is
the ordinary 30-dozeii egg case, made of white-
wood, using the so called odorless fillers. The term
whitewood is usually meant to include either poplar,
cotton wood or bass wood, but two or three other vari-
eties of wood, not so well known, are designated as
whitewood. Basswood is by some not placed in the
whitewood list, but the best authority known to the
writer says that basswood is as properly a whitewood
as poplar or southern whitewood. Poplar and cotton-
wood are most in use for storage purposes, and many
insist that basswood is objectionable because of its
liability to ferment or sour and cause tainted or musty
eggs. All kinds of cases have been in storage in the
house operated by the writer, and if all were thor-

80 EGGS IN COLD STORAGE.

oughly dry, no difference could be noted in the carry-
ing- qualities of the different kinds of whitewood, and
the preference has been for well seasoned basswood
cases. It may be that basswood is more likely to sour
and affect the eggs than poplar or cottonwood, but it
is always advisable to get stock for egg cases in the
fall and have them nailed up during- the winter, allow-
ing- two or three months for the cases to season before
the opening of the egg storing term. Some have dry
kilns for cases, but a naturally seasoned case is to be
preferred, as then it has a chance to deodorize as well
as dry out. In some localities other woods are used
for egg cases. Ash, maple, hemlock and spruce have
been used for storage cases, generally because they
are cheaper than whitewood in that locality. Any
strong scented wood like pine will not do because of
the flavor imparted to the eggs.

The pasteboard frames and the horizontal divid-
ing or separating boards which form for each egg an
individual cell in the case are usually spoken of as
fillers. For years only one grade of these was made
— those of ordinary strawboard. When moistened by
the evaporation from the eggs this material has a pe-
culiar rank odor, which was taken up to some extent
by the eggs if they were allowed to remain in the
fillers for several months. Much of the flavor result-
ing from a growth of fungus has been laid to the fill-
ers, and much of the flavor resulting from fillers has
been laid to a growth of fungus or must, but there is
no question but what strawboard fillers are not the
thing for cold storage use. Many kinds of fillers have
been tried, and many ideas suggested for the improve-
ment of cold storage eggs. A white wood pulp filler
made its appearance some years ago, but did not
come into general use. After being in storage a few
months, it absorbed moisture to such an extent as to
be very soft, and they were objectionable on this ac-
count. A good manila odorless is now on the market

EGGS IN COLD STORAGE. 81

which is giving- good satisfaction where tried. Ordi-
nary strawboard fillers have been coated with various
preparations, shellac, paraffine, whitewash, etc. Any
substance in the nature of waterproofing- might better
be left off for the reason, as we have seen, that eggs
must evaporate, and a waterproof filler would hold the
moisture and not allow it to escape into the air of the
room. It is essential to the well being of an egg that
it should evaporate, as proven by the experiments in
hermetically sealing, before described. Many have
gone to the expense of transferring the eggs into dry
fillers in the middle of the season. One season of this
was enough for the writer. A better way is to de-
crease the humidity of the room as the fillers become
more and more loaded with moisture. The humidity
may be decreased by the use of absorbents or by ven-
tilation, as already discussed in their proper places.
Fillers made of thin wood have been used in years
gone by with fair success, but tlieir manufacture has
now been entirely discontinued. They were made of
maple, shaved very thin, and were a prime filler so
far as odor was concerned, but in cold storage the
frames warp badly, and the time and eggs wasted in
getting the eggs out of the fillers was a serious item
against their use. As a shipping filler they were also
a failure because of the excessive breakage. Some
years ago an eastern company began the manufacture
of what is known as the odorless fillers. These fill-
ers are light brown or buff in color, and from the best
information the writer can obtain, are composed
largely of scrap paper stock, with some long fiber like
manila added for strength. In the manufacture the odorless
stock is treated to a thorough washing and deodoriz-
ing process, and the result is a filler with very little
odor. Eggs put up in these so called odorless fillers
and subjected to the same conditions as a similar
grade of eggs packed in common strawboard fillers,
generally come out of cold storage markedly superior.

82 EGGS IN COLD STORAGE.

A number of imitations of the original odorless filler
are now on the market, some of them almost if not
quite the equal of the original. Another filler which
has given good results is the fiber filler, which is made
from a material similar to the now well known fiber
ware. They have very little odor, and remain hard
and firm while in cold storage. A new odorless filler
made from pure spruce pulp has been put on the
market this season. This is a beautiful appearing
filler, and unless appearances and the ordinary tests
are deceptive will make its mark after a trial of a year
in cold storage to prove what it can do. A ventilated
filler made by a well known creamery supply house,
has been suggested as an ideal filler for cold storage,
but they are so poor mechanically that they are not
to be thought of. The material cut away to form
the air circulation space weakens the structure of the
filler to such an extent as to make it dangerous as a
shipping filler. Whatever filler is used, it should fit
the cases, not crowding in, nor still so loose as to
shake. If this point is looked after much breakage
and consequent poor results from storage in the cold
room may be avoided. *

ventilated Many styles of ventilated egg cases have been

tight cases. placed on the market in years past, but very few or
none survive the test of time. A ventilated case, made
by having the sides cut an inch narrower than the
ends, has come into use, especially in one large eastern
city. Making the sides narrower forms a space of
half an inch on both sides of case at top and bottom,
for the ready access of air to the interior of the case.
This case is of very simple construction, and efficient
in allowing a free circulation of air into the case.
Others, however, prefer a case with sides in two
pieces, claiming that the cracks will allow enough air
circulation. Still others prefer the shaved or veneered
cases with solid sides and bottom, claiming that this
kind of a case will prevent excessive evaporation

EGGS IN COLD STORAGE. 83

from the egg's. As pointed out elsewhere in these
articles, humidity and circulation have much to do
with the evaporation from eggs; in fact, are more of
a ruling factor than the package, although the package
necessarily has much to do with it. A tight package
will allow of less evaporation than an open one. In a
very dry room with a vigorous circulation a moder-
ately tight package is the thing, but in a compara-
tively moist room with poor circulation the more open
the package the better.

An appreciation of the poor circulation and damp storing eggs m

r r f trays or racks.

air of the overhead ice systems has caused many of
their operators to resort to the use of open trays or
racks for the storage of eggs. Very palatable eggs
have been turned out in this way, but the use of trays
in any ammonia or brine cooled room would lead to
very excessive shrinkage of the eggs and consequent
heavy loss in candling. On a commercial scale, too,
the storing of eggs in trays is hardly practicable, as
it increases the risk of breakage immensely, and the
eggs must be transferred from the cases when re-
ceived at the storage house, and back into cases again
when shipped, involving much labor, and perhaps loss
of valuable time at some stages of the market. In any
but a very moist room, eggs stored in open trays, in
bulk, will lose much from evaporation, and the loss
will be proportionately higher than on an equal grade
of eggs stored in ordinary cases and fillers. The ad-
vantage of trays, if any, for some houses, is that con-
tamination from fillers is avoided, and about 40 per
cent more eggs can be stored in a given space. The
eggs are, however, more liable to must as a result of
moisture condensing on their surface with change of
temperature, or on the introduction of warm goods
into the storage room.

The material used for forming a cushion in the
case on top and bottom of the fillers to protect the
eggs from contact with the case, and so that they will

KGGS IN COLD STORAGE.

Excelsior

TS.

cork shaving-s
for cushion.

Packing- eggs
in oats.

carry in shipping-, is generally either excelsior, which
is finely shaved wood, usually basswood, or the chips
made in the manufacture of corks, known as cork
shaving's. The big- cold storages recommend cork
now in preference to the best excelsior. Here again
comes a question of dryness. If the excelsior has
been in stock for a year and stored in a dry place it is
to be preferred to cork shavings, otherwise cork is the
best, because we know cork is always dry. Cork
makes a very poor cushion as compared to excelsior;
it is liable to shift in the case, leaving one side without
protection. As a matter of cost too, cork is much
more expensive than excelsior. A company known
to the writer manufacture a beautiful grade of bass-
wood excelsior, which is always fairly dry when re-
ceived, and makes as fine a cushion for protecting the
eggs as can be desired. If people want cork in
their cases they can have it by paying the price, but
dry, seasoned, fine- basswood excelsior is better, for
reasons stated.

Eggs have been packed in oats for years, but the
practice has gradually fallen off, as eggs stored in
cases from the best cold storage houses have been im-
proved in quality from year to year. Oats, if dry,
will absorb moisture from the egg quite rapidly, and
are objectionable on this account. If the oats are not
dry the germs of mold are developed rapidly, and as
the moisture is given off by the eggs, the mold will
grow, causing the eggs to become "musty." There-
fore the main difficulty in using oats as packing for
eggs in cold storage is to have them at the correct de-
gree of dryness. It is almost impossible to have them
in the same condition at all times. Oats have also been
used in cases inside the fillers, that is, the layers of
eggs are first put into the filler; then the oats are sifted
into the spaces around the eggs flush with the top of
the filler. This is repeated through the whole case;
all the space in the case not occupied by the eggs

EGGS IN COLD STORAGE. 85

being- filled with oats, excepting- the small space taken
by the fillers themselves, the object being-, of course,
to prevent the "fillers taste."

At intervals we read of some method of preserving- complicated

~ and obsolete

eg-g-s, which is said to be sure, to supersede or di- methods of pre-
serving- eg-g-s.

nary cold storag-e for the good keeping- of egg-s. A
scheme was tried on a larg-e scale somewhere across
the water, in which the eg-g-s were suspended in racks
in a cold room — the racks being- turned at regular in-
tervals by automatic machinery to keep the eg-g-s from
spoiling-, that is, to keep the yolk from attaching- to
the shell. A low temperature will prevent this, as
pointed out in the chapter on temperature, and why
a man should waste good energy inventing such a ma-
chine is passing all comprehension. The quantity of
various chemical preparations manufactured and sold
for egg pickling or preserving is even now quite large,
but the high class stock now turned out by the best
equipped cold storage houses has made any other
method of preserving eggs at the present day almost
entirely obsolete.

CHAPTER VII.

REMARKS.

some "dont's" ^ I ^HERE is a long string- of "don'ts " in regard to
SSHJtSf' 1 packing-, handling- and storing- egg's which might
be put down, but the writer will be content with a few
of the simpler and most useful ones. To start with,
don't store very dirty, stained, cracked, small or bad
appearing eggs of any description. Have your grade
as uniform as possible. The culled eggs will usually
bring within two cents of the market price, and it
pays better to let them go at a loss rather than try to
store them. Don't use fillers and cases the second
time; they are more likely to cause musty eggs than
new ones. Don't ship eggs in cold cars, or set eggs
which are intended for storage in ice boxes. In ship-
ping eggs from the producing section to the storage
house in refrigerator cars, no ice should be put in the
bunkers, because if the eggs are cooled down and ar-
rive at their destination during warm or humid
weather they will collect moisture or "sweat," and an
incipient growth of mold will result. Don't use heavy
strawboard fillers for storing eggs. If "the best way
to improve on a good thing is to have more of it," then
the best way to improve on a poor thing is to have less
of it; and if strawboard fillers are objectionable, then
the thinner they are the better, because less of the
material is present to flavor the eggs. Further, the
thin board fillers are more porous, and allow of a freer
circulation of air around the egg. As already stated,
odorless fillers are better than any strawboard fillers.
Don'tlise freshly cut excelsior. It should be stored
in a dry place at least six months. Use no other kind
but basswood or whitewood. Don't store your cases,
fillers or excelsior in a basement or any damp place.
Don't run warm goods into a room containing goods

KGGS IN COLD STORAGE. 87

already cooled when it can be avoided. For this rea-
son very large rooms are not to be desired. A small
room may be quickly filled with goods and closed until
goods begin to go out in the fall. If a large room is
used it may require several weeks to fill completely,
during which time the fluctuation of temperature is
at times excessive, causing condensation on the goods,
which will propagate must quickly.

To illustrate: We will suppose the egg room partly Don't put

r J warm egg's into

filled with goods cooled to a temperature of 30° F. Sev-acoldroom

1 along with eggs

eral cars of eggs at a temperature of, say, 70° F. are run already cooled.
into the same room. The new arrivals, in cooling to
the low temperature, give off large quantities of vapor
from cases, fillers and the eggs themselves, the vapor
condensing, of course, on any object in the room which
is below the dew point of the air from which the warm
goods came. This may seem like a finely spun theory,
but the writer has had some experience which amply
justifies this explanation. That the moist vapor given
oif by the warm goods does not show in the form of
beads of water, or fog, or steam, is no proof that it
does not exist. If the extremes of temperature are
as great as 25° F. condensation will occur on nine
days in ten during the egg storing season. The goods
already in storage are raised in temperature materi-
ally by placing in warm goods, which is harmful to
some degree. The logical deduction from above
seems to indicate that warm goods should not be
placed in a room with goods which have been reduced
to the carrying temperature. A separate room
should be provided for this purpose near the receiv-
ing room in which the goods coming in warm may be
cooled to very near the temperature of permanent
storage room. This is a refinement which small
houses cannot afford, and which most of the larger
ones do not have.

If you wish to progress compare your results with
those of others. Don't say: "My eggs are as good as

88 EGGS IN COLD STORAGE.

fresh"; test carefully from time to time through the
season, and compare quality with those from other
houses.

In the foregoing" articles I have given my own im-
pressions combined with the data and experience re-
ceived from others; but I do not care to be held abso-
lutely to any of the statements made, and reserve the
right to progress with the rest of you, and do not
consider myself bound by any hard and fast rule.

It should be positively understood that a mere
theoretical information on this subject is of only lim-
ited assistance; and those who undertake new work
are advised to put a man in charge who has had expe-
rience with the product which it is proposed to handle
in storage, as well as acquaintance with the mechanical
details of the plant.

ADVERTISEMENTS

Testing Eggs by Electric Light.

This picture is from a photograph of a couple of candling- booths, designed by the
author of "Eggs in Cold Storage." Each candler works by herself in a small room
closed on three sides by matched stuff, and on the fourth or front side by a heavy
curtain to keep out the light. These curtains are seen pushed back in the picture, so
that the interior of the booth may be photographed. The white boxes in the center of
the booths are candling boxes. They are pierced with two holes, and have an electric
light suspended inside A shelf, showing in the picture, runs around three sides of the
booth at a convenient height above the cases, for supporting fillers, dividing boards,
nails, hatchet, etc. The barrel is for the litter of various kinds (old newspapers, etc.)
which alwaj's accompany country packed eggs. The pail just above the barrel is for
rotten eggs. Cork shavings may be seen in the box between the two booths. The
advantage of each candler working independently will be appreciated by all familiar
with the work. The concise arrangement of this style booth makes a great saving in
space as compared to the ordinary candling room.

MADISON COOPER,

Refrigerating Engineer,

MINNEAPOLIS, MINN.,

410 First St., N.

Designer of "The Cooper Systems," Gravity Brine Circulation;

Positive Fan Ventilation and Forced Air Circulation.
Plans, Estimates and Personal Supervision of Construction.

Expert on the Successful Refrigeration of Perishable Products.

ADVERTISEMENTS

NEW YORK

OFFICE,

85 CHAMBERS

STREET

LONDON

OFFICE

106 HATTON

GARDEN, E. C.

41 ELIZABETH STREET

MAKERS OF

thermometers

FOR ALL

REFRIGERATING
ICE MAKING AND
COLD STORAGE

PURPOSES
THERMOMETER FOR

BRINE TANKS, PUMPS

AMMONIA PIPES

AND STILLS

INSULATED BRINE PIPE

THERMOMETER
FREE FROM FROST

CERTIFIED EGG ROOM

THERMOMETER, ETC.

FIG. A-L

uime for Refrigerating Catalogue

FIG. 31.

ADVERTISEMENTS

THE WHITLOCK COIL PIPE CO

ELMWOOD, CONN., II. S. A.

Pipe Coils of every descrip-
tion— for all purposes — made
of all kinds of metal, tubing-
or pipe. Manifolds and Re-
ceivers— Quarter Turns and
Manufacturers Return Bends.
of...

Wrought Iron Ammonia Coils

Dally capacity, 8,000 to 10,000 ^or Ice and Refrigeration Machines-
feet. Range, H to 4-inch pipe by the latest improved process, from
or tube. First-class workman- wrought iron pipe of the finest quality,
ship, prompt Tested by hydraulic or air pressure.

THE WHITLOCK COIL PIPE CO.

ELMWOOD, CONN., U. 5. A.

Cable Address, "Whitlock," Hartford

Directory Code.

Telephone Address, Elmwood

Carbonic -Anhydride System

ECONOMY | SAFETY

ODORUESS !SO!S-COI*RO«IVI.

This is the COMING ICE AND REFRIGERATING MACHINE ; applicable to all com-
mercial purposes. Superiorit}' established in numerous trials. Uses a harmless but
most efficient gas, and is equipped with reliable safety devices. Our Catalogue explains
all theoretical and technical details. If you are interested, write to

KROESCHELL BROS. ICE MACHINE Co,

29=39 ERIE STREET, CHICAGO, ILL.

ADVERTISEMENTS

44 "

The Cooper System

Forced Air Circulation.

BY THOSE

WHO KNOW.

F. R. NOONAN & CO*— Wholesale Butter and Eggs
and Cold Storage, Minneapolis, Minn.

"We have used your Forced Air Circulation in our Egg- Rooms for
the past two years, and are fully convinced that it is the only proper
way to carry eggs in cold storage.''

E. F. DUDLEY— Wholesale Butter and Eggs,
Owosso, Mich.

"I consider your Forced Air Circulation for Eg-g- Rooms very
fine. It gives the rooms bright, clear, fresh-smelling air and very
even temperature ; much better in this respect than the more com-
mon method of simply taking1 in fanned air at one or two opening's
in a room — to say nothing- of the behind-time systems of natural
draft."

PORTLAND ICE WORKS and PORTLAND ARTI-
FICIAL ICE CO,, Portland, Ore.

"I placed eight registered thermometers in different locations
in this larg-e Egg- Room. I never witnessed such a remarkable,
even scale of temperatures. With your system of Air Circulation
there is not a spot in this room where there is a difference of one-
tenth of a degree. The temperature is easily controlled. It can be
placed at any point desired, and held there without risk of any
kind.''

W. E. HARRIS,

Sup't Mechanical Department.

MADISON COOPER, Designer,

Minneapolis, Minn.

Compressed

Published monthly. Now in its fourth year. The only periodical devoted exclu-
sively to this subject. It is both theoretical and practical, progressive and up-to-date.
Subscription, $1.00 a 3rear. Foreign, $1.50. Send for sample copy.

Compressed Air> 26 CORTLANDT ST., N. Y.

ADVERTISEMENTS

EUGENE T. SKINKLE

("THE BOY")

lice flftaktri anb

IRefrioeratlng Engineer

ROOMS 30 AND 32

177 LA SALLE STREET

CHICAGO, ILL.

Plans and specifications for Ice Making and Refrig-
erating establishments, and consultation in relation to
buildings, machinery and apparatus, alterations and
repairs.

IReferences:

BIRMINGHAM ICE FACTORY CO., Birmingham, Ala.
CITY ICE MANUFACTURING CO., Chicago, 111.
LITTLE ROCK ICE CO., Little Rock, Ark.

EAST ST. LOUIS ICE AND COLD STORAGE CO., E. St. Louis, 111.
KINGSTON ICE MAKING CO., Limited, King-ston, Jamaica, West Indies
GEO. CHALLONER'S SONS CO., Oshkosh, Wis.

EL RENO ICE AND COAL CO., El Reno, Okl.
MONROE CATERING CO., Chicago, 111.

KING'S RESTAURANT, Chicago, 111.

AMERICAN RESTAURANT, Chicago, 111.
And Many Others.

Hce flDafeitiQ anfc IRefrigeratiriQ Supplies

AD VKR TISEMENTS

The Recognized Authority in all
Cold Storage Matters.

A MONTHLY REVIEW OF THE ICE, ICE MAKING, REFRIGERATING. COLD STORAGE AND

KINDRED TRADES.

SUBSCRIPTION PRICE

In United States, Canada and Mexico, . . - .

In all other countries, . .

PAYABLE IN ADVANCE.

$2.00 per year
3.00 per year

H. S. RICH & CO.

206 Broadway, NEW YORK

PUBLISHERS

177 La Salle Street, CHICAGO

Also publishers of the following Standard Rooks on Cold Storage, Ice Making
and Refrigeration:

Gompenft of /Ibecbanfcal IRefrigeration

By PROF. J. E. SIEBEL.

PRICE. PREPAID. CLOTH, $3.00; MOROCCO. $3.50.

The only work treating- of all the various branches of theoretical and applied
refrigeration, and will be found to contain a larg-e amount of information which would be
looked for in vain elsewhere.

practical 1lcc /Rafting and IRefruieratuui

By EUGENE T. SKINKLE.
PRICE, PREPAID, CLOTH, $1.50; MOROCCO $2.00.

Ever}7 branch of ice making and refrigerating- is handled.in this work, with a view
to setting- out the best and most economical practice in the construction and operation
of the plant.

Ifnfcicattns tbe 1Refn0eratin0

By GARDNER T. VOORHEES.
PRICE. PREPAID. CLOTH, $1.00; MOROCCO, $1 50.

Treats of the application of the indicator to the ammonia compressor and steam
eng-ine, with practical instructions relating- to the construction and use of the indicator
and reading- and computing- indicator cards.

ADVERTISEMENTS

HEADQUARTERS FOR

Chloride
Calcium

Prime white, full strength, packed in 600-pound iron drums.
Representing- the largest output in the country, we are in condi-
tion to name interesting- prices for car lots or less quantities.

PETER VAN SCHAACK & SONS

138-140 LAKE STREET,-CHICAGO.

ACCURATE THERMOMETERS.

Thermometers bought from us at one time give the same result

as thermometers bought from us at

any other time.

Prof. Marvin's Sling Psychrometer

for the exact determination of moisture in the air, is made
with the utmost care and is the best of its class.

ALL THERMOMETERS MADE BY US ARE
GRADUATED AND ETCHED ON THE STEM.

Send for a Sample of our Storage Room Thermometer.
Price, $1.00 each.

SCHNEIDER BROS.

265 Greene Street.. ..NEW YORK

Makers to.. .UNITED STATES WEATHER BUREAU.

SIGNAL CORPS UNITED STATES ARMY.
FISH COMMISSION.

ADVERTISEMENTS

25° BEIiOOl ZERO

OBTAINED WITH THE

FEATURES:

MAXIMUM CAPACITY SIMPLICITY

HIGHEST ECONOMY- DURABILITY
SPECIALLY ADAPTED FOR VENTILATING SYSTEMS

FOR PARTICULARS ADDRESS

THE

CARBONDALE, PA.

NEW YORK OFFICE, 1012 HAVEMEYER BUILDING.

NONPAREIL CORK

Che Ideal
Insulation

Sheets for
Walls
Rooms
Ceilings.

3- feet

Sections for

Steam, Brine

Ammonia

and
Water Pipes

Ui^b WOtvK! says"THEBOY"

in his Practical Ice Making and Refrigerating,
page 164,

"In the selection of insulating- substances
their power to withstand moisture plays an im-
portant part in most cases. In this respect Cork
is a very desirable material," says Professor
J. E. SIEBEL in his Compend of Mechanical Refrig-
eration, page 155.

The Nonpareil Cork Mfg. Co.

28 QUEEN STREET,

LONDON, E* C, ENG.

92 WEST BROADWAY,

NEW YORK, N. Y.

A D VKK TISKMEN TS

Tee and Refrigerating machines

FOR CREAMERIES AND
PRODUCE DEALERS

Refrigerating Machines are rapidly taking the place of
ice for refrigerating purposes. A lower temperature can
be secured. The cold is absolutely dry. It will pay you to
investigate and get estimate on plant.

SIMPLE
STRONG
COMPACT
DURABLE

ijr

LARGEST
EFFICIENCY
POSSIBLE BE-
CAUSE ABSO-
LUTELY NO
CLEARANCE

THE ONLY SMALL MACHINES OF DUPLEX TYPE

EQUIVALENT TO TWO INDEPENDENT MACHINES. ONE
ALWAYS IN RESERVE AS PROTECTION AGAINST
LOSS FROM STOPPAGES AND BREAK DOWNS.

Small Plants from 2 to 10 Coits Refrigerating Capacity Our Specialty

Estimates Cheerfully and Promptly Given.

Write for our Handsomely Illustrated Booklet named ''Cold Making."

CREAMERY PACKAGE MANFG. Co,

1, 3 AND 5 WEST WASHINGTON STREET

CHICAGO, ILL.

Doo
and

THIS BOOK IS DUE ON THE LAST DATE
STAMPED BELOW

AN INITIAL FINE OF 25 CENTS

WILL BE ASSESSED FOR FAILURE TO RETURN
HIS BOOK ON THE DATE DUE. THE PENALTY
WILL INCREASE TO SO CENTS ON THE FOURTH

OVERDUE. T° $'-°° °N ™E SEVEN™ DAY

fasten

fix

iru

I They
^mplete
Wftt 3 1933 1 place,

air in either direction.

le with

f-ewith,
hresh-
[e d to
go on a
th nei-
thresh-
have
erhead
d corn-
in ad-
pr so it
[mashed
trolley.

, or all

opened
re cush-

LD 21-50m-l,'33 rush of

;

Complete information, diagrams and illustrations
in our circulars.

FRICK COMPANY

..ENGINEERS...

Established

Incorpo
188:

288

ies

IVERSITY OF CALIFORNIA LIBRARY

References and new Ice Machine Circular, describ-
ing1 latest improvements ->"^ — " .»vinR;
Ice arul u.- •,:.,. .eratir.- iild< . fir*
class STEAAl oNUiNES, AMMON.
VALVES, FLANGES, COILS, etc.

CORLISS STEAM ENGINES

ICE MAKING MACHINERY,

STEAM BOILERS,
AMMONIA FITTINGS.

FRICK COMPANY,

WAYNESBORO, FRANKLIN COUNTY, PA.

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