A’/-

Quarterly Journal

of the

Florida Academy
of Scieucesf

J '

[FORMERLY PROCEEDINGS OF

FEB 7

I^ORIDA ^

ACADEMY OF SCIENCES

Vol.8

December, 1945

No. 4

Contents

Page

Bless — Atomic Ei^ergy 267

Koenig — The Establishment of Mussolini ^s

Neofascist State 280

Mustard — The Pectin Content of the Persian Lime 290

Brannon — Factors Affecting the Growth of

Myxophyceae in Florida 296

Netting and Goin — The Cricket-frog of

Peninsular Florida 304

Tyner — Properties of Limerock Concrete.

.311

December, 1945

Vol. 8, Number 4

QUARTERLY JOURNAL OF THE
FLORIDA ACADEMY OF SCIENCES

A Journal of Scientific Investigation and Research

Published by the Florida Academy of Sciences
Printed by the Rose Printing Company, Tallahassee, Florida

Communications for the editor and all manuscripts should be addressed to
Frank N. Young, Editor, University of Florida, Gainesville, Florida.
Business communications should be addressed to Taylor R. Alexander,
Secretary-Treasurer, University of Miami, Coral Gables, Florida. All
exchanges and communications regarding exchanges should be sent to
thd Florida Academy of Sciences, Exchange Library, Department of
Biology, University of Florida, Gainesville.

Entered at the Post Office at Tallahassee, Florida, as second class matter.

Subscription price. Three Dollars a year.

Mailed November 19, 1946

ATOMIC ENERGY

A. A. Bless
University of Florida

1. The Atom

This year we are celebrating the fiftieth anniversary of the
discovery of X-rays. There is another fiftieth anniversary which
is, perhaps, just as important, namely, the discovery of the electron
and the beginning of atomic physics.

Until 1895 the atom was considered to be a sphere of invariable
composition. The atom of oxygen, for example, was assumed to
be a sphere with every part having the same composition, and
the composition of one atom being totally different from that of
any other atom. The universe of matter was assumed to consist
of 92 distinct building blocks or elements. In 1895, J. J. Thompson
and other workers discovered that all materials contain negatively
charged particles, electrons. If matter contains negative charges,
it must also contain an equal number of positive charges, since
matter in its ordinary state is electrically neutral. The elementary
units of matter, the atoms, must therefore have a structure con-
sisting of an equal number of positively and negatively charged
particles. The manner in which these particles must be arranged
so as to provide the observed stability of atoms is a whole story
in itself, and we cannot go into it now. The picture of the present
day atom evolved slowly, but by the end of the first quarter of
this century, the picture was fairly clear. The atom is assumed
to have a positively charged nucleus situated at its center and
negative charges, electrons, whirling around at various distances
from the nucleus. Fig. 1. The number of charges on the nucleus
of any element turned out to be equal to the order number of the
element in the periodic table. Thus, hydrogen had one positive
charge on its nucleus; helium, two; lithium, three; boron, four;
etc. The number of electrons outside the nucleus was naturally
equal to the number of positive charges on the nucleus, since the
atom in its usual state is neutral, as mentioned before.

Regardless of what was done to the electrons, the nature of
the element did not change. Electrons could be expelled from a
given atom, and then the atom would be in an ionized state,
but it would still remain the same atom. It did not exist long
in this state of ionization and very soon acquired a number of
electrons equal to the positive charge on the nucleus.

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JOURNAL OF FLORIDA ACADEMY OF SCIENCES

The disturbance of the electrons creates light rays, ultraviolet
rays or X-rays, depending on the number of the electrons and
their closeness to the nucleus. The configuration of the electrons
is also responsible for the chemical and physical properties of the
material.

In the last analysis all these properties depend on the number
of positive charges on the nucleus. So long as the number of posi-
tive charges on the nucleus remains the same, the number of elec-
trons and their configuration remains the same, so that the chemi-
cal properties, as well as the radiations emitted by the atom when
disturbed, remain essentially the same. In order to change the
chemical properties, or to change the nature of the radiation, the
number of positive charges on the nucleus must be changed, which
in turn changes the number of electrons outside the nucleus and
their configuration.

\

Fig. 1 — The atom consists of a positively charged nucleus with negative
electrons moving around it. The nucleus contains most
of the mass of the atom.

The size of the nucleus and of the electron is of the order of
about 10"^^ cm in diameter, which is extremely small compared to
the size of the atom, the latter having a diameter of about 10"® cm.
The distance, for example, between the nucleus of the hydrogen
atom and its electron is 10,000 times as great as the size of either
the nucleus or the electron. The space occupied by these particles
is thus an infinitesimal fraction of the total space occupied by the
atoms. This fact has a great deal to do with the utilization of
atomic energy.

2. The Nucleus

As mentioned before, the nucleus contains a number of positive
charges equal to the order number (or the atomic number, as it is

ATOMIC ENERGY

269

sometimes called) of the element in the periodic table. Each posi-
tive charge is associated with a mass equal to the mass of the nucleus
of the hydrogen atom. The atom of sodium, for example, the elev-
enth element of the periodic table, contains eleven hydrogen nuclei,
or protons, as they are often called. However, the atomic weight
of the element is 23. This means that the element must have 23
units of mass on the basis of oxygen having 16 units. This also
means that the nucleus of the sodium atom must contain approxi-
mately 23 times as many mass units as a proton. Since it already
has 11 protons, it needs, therefore, 12 more mass units which have
no charge on them. These mass units are called neutrons. Each
atom, therefore, contains as many protons as is equal to its
atomic number, and enough neutrons to complete its atomic weight.
So long as an atom has a given number of protons, it will possess
certain definite chemical and physical properties, regardless of the
number of neutrons it possesses. For example, the element of
sodium may have 12 neutrons or 13 neutrons, its atomic weight
being consequently either 23 or 24. (Substances which have the
same number of nuclear charges but different weights are called
isotopes). However, so long as the number of positive charges re-
mains the same, all physical properties of the element, with the ex-
ception of its mass, remain essentially the same. Similarly, the
hydrogen atom has a nucleus consisting of one proton; deuter-
ium or heavy hydrogen has a nucleus consisting of a proton and
a neutron. While the mass of the deuterium nucleus is thus double
that of the light hydrogen, the properties of heavy hydrogen re-
main essentially the same as those of light hydrogen, since it con-
tains only one positive charge.

The nucleus (and the atom as well) is completely specified by
the number of positive charges and the number of mass units it
contains. It is customary to place the number of charges in the
lower left and the number of mass units in upper right of the
chemical symbol of the element. For example, sodium with 11
charges and 23 mass units is represented as uNa^^; its heavier
isotopes as uNa^^. The light and the heavy hydrogen are re-
spectively iH^, iH^. The notation stands for carbon with 6

units of charge and 12 mass units. is the nuclear symbol for

the neutron since it contains no positive charges and has one mass
unit.

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JOURNAL OF FLORIDA ACADEMY OF SCIENCES

3. Eadioactivity: Transmutation of Elements.

While most of the atoms are very stable, many, particularly
among the heavy ones, are not. Becquerel, in 1896, found that
uranium atoms eject alpha, beta, and gamma rays. The alpha rays
turned out to be nuclei of helium atoms, (symbol: 2He^), while the
beta rays are high speed electrons; the gamma rays are merely
short wave X-rays, emitted presumably because of the excitation
of the atom. The process of ejection of particles from the nucleus
is called radioactivity. The ejection of a negative charge moves
the element up one place in the periodic table, since the number of
positive charges on the nucleus then increases; while the ejection
of positive charges lowers the place of the element in the periodic
table.

The lowering or the raising of the number of positive charges
on the nucleus and thus the changing of one element into another

,H.' +

Fig. 2 — Pictorial representation of the formation of carbon out of
berillium. Neutrons are represented by blank circles, while protons
are circles with a plus sign.

may be accomplished by a number of agents : ultra short gamma
rays, or high speed particles such as electrons, alpha particles, neu-
trons, protons, heavy hydrogen atoms, etc. An illustration of such
a process is the change by the aid of fast alpha particles of the
beryllium atom into carbon with the ejection of a neutron. The
reaction can be represented thus : (Fig. 2) : 2He^+4Be®”^6C^2+

©n^+E.

In this reaction we use the same principle of balancing as in an
ordinary chemical reaction. The number of charges of the product
and also the number or mass particles in the product must be equal
to the number of charges and mass particles in the reactants. The
number of positive charges of He and Be (6) is equal to that of C.

ATOMIC ENERGY

271

Similarly, the number of mass units of the reactants (13) is equal
to the number of mass units of the product (12-|-1). In most
nuclear reactions some of the particles move with great speed and
thus have large kinetic energy. The term E represents the excess
kinetic energy of the product over that of the reactants. More wiU
be said about E later. It sometimes happens that the bombard-
ment of an atom by means of particles results in the formation of
an element of a lower atomic number. This occurs when the num-
ber of positive charges emitted in the process by the new element
is greater than the number of positive charges it receives from
bombardment.

Transmutation of elements thus became a reality. The old
dream of the alchemist was realized, when man was able to make
gold out of baser elements. This transmutation was accomplished,
however, not by the aid of the ^‘philosopher's stone,’’ but by the
aid of more realistic devices such as cyclotrons. Van de Graaff
machines, etc. These devices give to particles, such as heavy hy-
drogen, the high speeds necessary to break through or into the
nucleus. The process of formation of gold out of mercury by
these means is much too expensive to be commercially profitable.
However, some substances formed in this way are worth much
more than gold. In this class belong the so-called man-made
radioactive substances.

4. Tracer Elements

Occasionally the material resulting from bombardment is not
stable ; it is emitting particles and rays similar to those of naturally
radioactive substances. Such substances were thus termed arti-
ficially radioactive. These man-made radioactive substances are
just as effective in the treatment of diseases as the naturally radio-
active substances, and can be more cheaply produced. Moreover,
many of them proved to be of extreme value in biological investiga-
tions. Some substances are absolutely essential for the well-being
of plants or animals, even though the amount of that substance
taken in by the organism is too small to be measured by chemical
means. However, if these substances are made radioactive, it is
possible, by means of special detectors, to trace the progress of the
element in the digestive system of the animal, and thus study di-
rectly the effects of the element on the various portions of the di-
gestive system. Sodium, for example, is made radioactive by bom-
bardment with heavy hydrogen. The radioactive atoms fed to
animals or plants will betray their progress in the digestive system
through the rays that they are emitting. These rays are detected

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JOURNAL OF FLORIDA ACADEMY OF SCIENCES

by special devices, so-called Geiger counters, the operation of which
we cannot discuss here.

5. Uranium Fission

The process of artificial transmutation was so well developed
during the last decade that practically every element in the period-
ic table was made artificially. Many scientists were intrigued by
the probability of being able to form new elements beyond the
uranium atom, the last or heaviest element known, by bombarding
uranium. While some evidence was obtained that the bombard-
ment of uranium yielded transuranic atoms, there was also evi-
dence of an entirely new kind. It was found that some of the
products of the bombardment of uranium, instead of differing
from uranium by very few units in mass or in charge, actually
differed from the uranium atom by a great deal. In other words,
evidence was discovered that uranium was split into two fragments
of nearly equal size, such as seBa and seKr; ssLa and siRb; 54Xe
and 38 Sr ; 53I and 39Y ; 52Te and 40Z. In most cases the elements
so formed are unstable isotopes of the common stable elements.
This was the first time that splitting (or fission as it is often called)
of an atom was accomplished. Also, in common with other nuclear
reactions, the products of disintegration had a great deal of kinetic
energy; they were moving with tremendous speeds. These speeds
were equivalent to those of electrons acted on by 200,000,000 volts,
or to the average speed of particles at a temperature of a trillion
degrees.

6. Matter Energy

In order to understand the origin of this kinetic energy, we
must go back to a principle of equivalence of mass and energy
which was given by Einstein in 1905 in connection with his theory
of relativity. Einstein at that time showed from theoretical con-
siderations that a given mass, m, corresponds to an amount of
energy given by the relation E=mc^. For example, one gram of
mass or of matter is equivalent to an amount of energy equal to
9 X 10^^ ergs or 9 x 10^^ joules. This relation was verified in a
great variety of ways.

It is important to understand the distinction between chemical
energy and this matter energy. In the case of chemical energy, re-
sulting, for example, from the combustion of 1 gram of coal or
gasoline, the total mass of the products of combustion is equal to
the mass with which the reaction was started. One gram of coal,
upon combustion, yields approximately 10,000 calories. This energy
is released entirely at the expense of the configuration of the elec-

ATOlMilC ENERGY

trons. Matter, so far as is now known, takes no part in this reaction.
On the other hand, when matter is transformed into energy in ac-
cordance with the relation E=mc^, the matter itself disappears. All
of the energy is at the expense of the material, none of which is
left. The amount of energy given off by one gram of matter in
this kind of reaction is about a billion times as great as the amount
of energy given off at the expense of electron configuration. The
difference in the quantity of energy developed by the two processes
may be understood from this example: the complete combustion
of a pound of coal and the complete utilization of all of the energy
of combustion would raise the battleship Missouri (which weighs
45,000 tons) to a height of about 1.5 inches. On the other hand,
the energy realized from the transformation of 1 pound of matter

ENERGY OF COMBUSTION

5 K.W. H.

I LB. COAL I LB. PRODUCTS

ATOMIC ENERGY

I LB. MATTER

i __ I -|- 5,000,000,000

NO PRODUCTS KW.H.

Pig. 3 — Comparison of energy of combustion and energy of matter.

would be sufficient to raise the battleship Missouri the total dis-
tance from here to the moon. The energy obtained from the dis-
appearance of one pound of matter would provide more than 5
billion kilowatt hours (Fig. 3).

It was found that in the disintegration of uranium, the total
mass was slightly (about 0.1%) less than the mass of the reacting
elements, and this loss of about 1/1000 of the mass accounts for
the high energy observed in the process of fission.

7. U-235 Disintegration Chain. Reaction

After a great deal of study, it was found that the fission pro-
cess is supplied, not by the common 9211^^®, hut by an isotope, name-

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JOURNAL OF FLORIDA ACADEMY OF SCIENCES

ly, U-235, or those uranium atoms which have 92 positive charges
and only 143 neutrons instead of 146 neutrons possesssed by the
normal uranium atom. This U-235, on splitting into fragments,
emits also from 1 to 3 neutrons. These neutrons, in turn, are cap-
able of affecting other U-235 atoms, and if, in their flight, they do
encounter U-235 atoms, more fission will result with the conse-
quent emission of more energy and ejection of new neutrons, and
so on. This was the first time that products of a nuclear reaction
were such as to enable the process to go on, and so provide a chain
reaction. Since the time it takes for the splitting of the atom and
the ejection of new neutrons is extremely short, the energy devel-
oped in a very short time is so great that an explosion is bound to
result. The speed with which such a reaction proceeds is greater
even than the speed with which TNT explodes. Since the energy
developed by one pound of U-235 during a nuclear reaction is very
much greater than the energy developed by a ton of TNT, the ex-
plosive possibilities of this reaction become evident.

While deposits of uranium ore are reasonably common, most of
the uranium atoms are of the U-238 type, which is difficult to split,
the U-235 fraction being only about 0.7 % of the total. In the nor-
mal mass of uranium metal there are too few U-235 atoms to pro-
vide a chain reaction. Neutrons emitted in the splitting of the
first one or two atoms of U-235 may never hit another such atom
unless the percentage of these atoms in the material is much
greater. If energy is to be utilized by the bombardment of U-235
atoms by means of neutrons, there must be a greater concentration
of these atoms. This concentration may be provided by separat-
ing these atoms from the common U-238 variety. The separation
of atoms when they have different chemical characteristics is
fairly easy, because it can be obtained by precipitation of one
element from another by utilizing the difference in the combining
power of the two elements. However, in the case of the two
uranium isotopes, this evidently is impossible because the chem-
ical properties of the two are similar. In their separation, the
only property which is different in the two elements, namely, the
mass of the atoms, must be utilized.

The separation of isotopes may be made in a great variety of
ways. It is known that lighter atoms diffuse more easily through
a given porous membrane. After diffusion, the fraction of the
lighter element in the mass which has diffused is slightly greater
than before diffusion. By making a given quantity of material
diffuse a great many times, each time using only the fraction

ATOMilC ENERGY

275

which passed through the membrane first, each succeeding pro-
duct has higher concentration of the lighter element than the
preceding and in this way the partial separation of U-23’5 atoms
may be accomplished. Another method of separation is by
thermal diffusion. This is very similar to diffusion through a
porous membrane. The lighter elements possess a slightly higher
velocity at a given temperature than a similar fraction of the
heavier elements. If the faster portion of the gaseous product
is removed and evaporated again, the fraction of the U-235 atoms
in each new batch will be higher with each new evaporation than
in the preceding.

There is one other difficulty with the utilization of the energy
that accompanies the fission of the U-235 atom. The neutrons
which are ejected as a result of the fission have too high a speed
to produce new products of fission. It is found that slow neutrons
are more effective in producing fission of uranium-235 ; they are
captured more easily by the uranium nucleus than the fast
neutrons. The problem of slowing the original neutrons ejected
in the process of fission is solved by mixing the U-235 atoms with
a moderator. A moderator is a substance which does not absorb
neutrons, but merely slows them down. It was found that ele-
ments of low atomic weight, such as heavy water, graphite and
paraffine, make efficient moderators; they slow down neutrons,
without capturing them. The chance of neutrons, upon their
slowing, of being captured by U-235 atoms, is greatly enhanced.
(Fig. 4.).

8. The Critical Size of a Bomb

It was pointed out before that the size of the nucleus and of
the electrons is a small fraction of the total size of the atom. If
the nucleus is taken as a sphere with a diameter of about 1/4 inch,
the atom would be a sphere with a diameter of 200 feet, and this
would be the distance between the nuclei of two adjacent atoms.
The chance that neutrons emitted by a given atom would strike
another atom close to it is extremely small because the nuclei
occupy such a small part of the total space. If there is to be a
chain reaction, we must provide enough material so that one or
two neutrons from each of the disintegrating atoms of uranium
are sure to strike another nucleus of U-235. If enough material
is provided so that no matter in which directions neutrons are
traveling they will hit another nucleus, the chain reaction will
proceed. If the amount of material is insufficient, the reaction
will stop after one, two, or a few more uranium atoms have been
broken up. It follows therefore, that there is a critical size for

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JOURNAL. OF FLORIDA ACADEMY OF SCIENCES

ATOMaC ENERGY

277

the amount of material that must be used in a chain reaction. If
the amount of material used is less than that, the reaction will not
proceed; if the amount of material is greater than that, the re-
action will proceed with great violence. This shows that it is
perfectly safe to store a given quantity of U-235 so long as it is
considerably smaller than the critical size. Bringing two or three
such safe masses together will give a mass which is greater than
the critical size and will allow the chain reaction to take place with
the consequent explosion.

9. Neptunium and Plutonium

For a while, U-235 seemed to be the only source of atomic
energy. However, very early in the study of fission it was pre-
dicted that an element beyond uranium, one whose atomic
number (or whose number of positive charges) is 94, would be as
susceptible to fission as U-235. The production of such an ele-
ment is accomplished by the bombardment of U-238 with fast
neutrons. The elements resulting from that bombardment are
shown by the following reaction:

238 1 239 0 239 239 0

U n Ne -j- e ; Ne Pu -j- e

92 0 93 -1 93 94 -1

The first product of the reaction is neptunium. This element, on
ejection of a negative charge, becomes plutonium, with an atomic
number 94, and an atomic weight 239. Since it is a different
element, plutonium has different chemical properties, and its
separation from uranium may be accomplished by chemical
means.

The probability of formation of plutonium out of U-238 is
greatly increased if the neutrons have just the right energy,
intermediate between the high energy of neutrons emitted in the
process of U-235 fission, and the low energy neutrons, which are
most effective in producing fission. The slowing down of neu-
trons emitted in the fission process must be such that some of
them have just the right velocity range for plutonium formation,
while others have the right velocity range for U-235 fission, so
that the chain process could be continued. The problem was
solved satisfactorily, and by the end of the War plutonium was
being produced in fairly large quantities. The metal had the
predicted properties. (Fig. 4.).

10. Peacetime Uses of Atomic Energy

The process of formation of plutonium out of uranium is very
promising from the standpoint of utilization of atomic energy for
peaceful purposes. The process, though it involves great evolu-

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JOURNAL OF FLORIDA ACADEMY OF SCIENCES

tion of energy, can be made to take place slowly enough to pre-
vent explosion. In order to keep the process going, a given mass
of uranium metal must be enriched with a considerable quantity
of U-235 in order to provide the chain reaction. The splitting of
U’235 provides neutrons for the formation of plutonium out of
U-238, and it also provides neutrons for splitting of other U-235
atoms and for continuing the chain reaction. The process is
stopped periodically and the plutonium is removed by chemical
means. This metal itself may then be used as the spark plug for
the chain process. As we have seen, the disintegration of U-235
creates a great amount of heat. In order to lower the temperature
of the whole mass a cooling agent, such as water, must be used.
The energy of the hot water can then be utilized without any
great difficulty for peaceful purposes.

If the heat energy is to be utilized in engines or similar labor
saving devices, the temperature of the reaction must be very
high. The high temperature would create serious difficulties in
the process of formation of plutonium ; however, it is quite likely
that such difficulties will be overcome and atomic energy may
be used in large stationary installations. On the basis of our
present knowledge of atomic energy the probability of using
small amounts of such an agent as U-235 to propel planes or other
mobile engines is extremely small.

11. Conclusion

The development of our understanding of atomic processes
leading to the utilization of matter energy discussed in the pre-
ceding pages, does not give the reader any idea concerning the
tasks that had to be performed and difficulties that had to be
overcome before the final product was obtained. Literally thou-
sands of problems had to be solved, thousands of calculations
had to be made in a very short time before the first atomic bomb
was allowed to explode in New Mexico. Every step was over
untried ground. The official report of the project by Smyth
gives only a very faint idea of the magnitude of the task involved.
Paraphrasing Churchill one may with justice say that at no
period in the history of science has so much been done by so few
in so short a time. It will stand as a magnificent scientific
achievement.

On the other side of the ledger is the fact that at no time in
the history of humanity has a weapon so destructive, so vicious
in its possibilities, been let loose on humanity. The explosive
force of this weapon defies imagination. But this is not all. The
amount of radioactivity involved in the process of explosion and

ATOMIC ENERGY

279

in the process of disintegration of the atoms is such as has never
been witnessed by humanity. The total amount of the radio-
active materials in all hospitals in the United States is a fraction
of a pound. One thousandth part of a pound of radioactive ma-
terial such as used in the treatment of cancer, if allowed to spill
in a good-sized room would make that room uninhabitable. In
the case of the bomb, many pounds of radioactive material are
dropped in a relatively small area. The harmful possibilities of
such a concentration of radioactivity can only be dimly realized.
It is a poison against which no gas masks are of any avail. The
duration of the radioactivity is not yet fully known, but certainly
it is much longer than any lethal gas that has ever been invented.

Needless to say, scientists are aware of the terrible effects of
this weapon. As a consequence, they are taking greater interest
in the social aspects of our national and international life. This
is indicated by the stand that scientific societies are now taking
with reference to questions of international organization. If, as
a result of the atomic bomb, the scientists of the world will exert
greater influence on social affairs and bring to the solution of
these questions the qualities of objectivity, understanding, and
intellectual honesty which are the prime prerequisites for all
scientific discovery and the same qualities which have enabled
scientists to create this bomb, the dropping of the bomb will
have been a blessing to this world. If, on the other hand, the
solution of all social problems is left in the same hands that have
guided the world in the past, that have brought so much misery
and pain, the addition of the atomic energy may well be the last
straw needed to finish off this world.

THE ESTABLISHMENT OF MUSSOLINI’S
NEO-FASCIST STATE

Duane Koenig
University of Miami

For more than eighteen months after the surrender of Italy
in September of 1943, Benito Mussolini served as Adolf Hitler’s
quisling in the Nazi occupied areas of the Peninsula. The spec-
tacle of the erstwhile Sawdust Caesar cravenly accepting crumbs
from the hands of his former protege quite naturally aroused
derision throughout Italy and the entire world. Yet this phe-
nomenon went deeper and bore graver implications for the history
of the country than might appear at first hand. It is the purpose
of this paper to show how Mussolini was set up as Hitler’s Italian
puppet, and to indicate the importance of that development.

One distinction should be drawn at the outset. The revival of
Fascism came about as a necessary alliance between two
divergent viewpoints. To the Germans, it was a mere incident
in their effort to use Italy for the immediate and limited purpose
of war. To Italian reactionaries, it was the logical outcome of
the Fascist experience, 1922-43.

* * *

When on September 8, 1943, General Dwight D. Eisenhower
announced Italy’s capitulation, the German government was
forced to decide between risking a hasty occupation of the king-
dom or allowing Italy to be taken over by the Anglo-Americans.
Once the military occupation was determined, the Nazis had
the choice of governing the overrun territories in their own name
or by means of puppets. The task facing an army of occupation
is to rule with the least possible trouble and the fewest possible
soldiers. A collaborationist regime will relieve the conqueror of
tedious and time-consuming administrative detail. In the case of
Italy, such a government might rally certain blocs of public
opinion to the assistance of the Nazis and prevent some military
units and equipment from falling into the hands of the Allies.
Thus it was that, although after the collapse of his original part-
ner the Fuehrer spoke of Italy as having been a “liability” to the
Reich, at the same time he sponsored the organization of a
Fascist quisling dictatorship.

The first indication that the Germans intended to set up a
puppet government in the Italian areas under their control came

280

ESTABLISHMENT OF MUSSOLINI’S NEO-FASCIST STATE 281

over the Nazi Zeesen radio station early on September 9, barely
twenty-four hours after the Eisenhower broadcast. The German
radio spoke of the formation in Italy of “a National Fascist gov-
ernment speaking in the name of Mussolini/’ and called for
Fascist volunteers to enroll immediately for the purpose of
resurrecting the Party and committing acts of sabotage- against
the Allied forces. Soldiers and airmen were ordered to destroy
all installations, to refuse to give up their arms ; railway workers
were told to cease operating the trains. That this reanimated
Fascist government existed in name only was patent, for the
first proclamation of the new regime did not even mention a
single minister of state or other official connected with it beside
Mussolini. The broadcast, preceded by the playing of the Fascist
anthem Giovinezza, stressed particularly that ‘The Badoglio be-
trayal will not be perpetrated,” that all turncoats would be
punished, and that the revivified Fascism (called by the Allies
“neo-Fascism”) would be concerned with fundamental social
reform.

The days following September 9 were used by the Germans to
extend and consolidate their control of central and northern
Italy. The cities of Milan, Turin, Verona, and Bologna were
scenes of much disorder. Bitter clashes between German and
Italian troops and between Germans and partisans were reported
for almost a fortnight before opposition was reduced and the
patriots disarmed. The chaos made the distribution of food diffi-
cult and bread riots were common. The capital city of Borne
quickly fell to the Nazis with King Victor Emmanuel and Premier
Pietro Badoglio barely making their escape.

Except for periodic promises that the Bepublican Fascist
government’s composition would be announced shortly, little was
known definitely, but it was believed that some sort of cabinet
of collaboration was impending. Weight was added to this
opinion by a German announcement of the 10th that the Badoglio
regime no longer existed. Meanwhile, Allied newspapers specu-
lated whether Koberto Farinacci, one of the more rabid Fascists,
might not be selected as the Italian quisling. Mussolini was still
held as prisoner by Badoglio and, even if rescued, no one knew
whether he would consent to serve under the Germans. One
newspaper recounted the alleged statement to his barber that the
Duce made after his arrest, “You must know that I always was
and (always) will remain a good Italian.” The paper added,
“Many Italians doubt whether Mussolini is ready to accept the
planned collaboration.”

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JOURNAL OF FLORIDA ACADEMY OF SCIENCES

Lacking though information might be about a Republican
Fascist government, the German methods of domination were
those which had been time-tested in the other occupied countries.
Martial law was proclaimed and local governmental authorities
were made responsible for the behavior of the populace in their
districts. The German military divided occupied Italy into two
zones, north and south, except for Rome which had a separate
administration.

By virtue of an agreement concluded at 4 :00 p.m., September
10, between the Nazis and the Italians, control over the Eternal
City was to be exercised through an Italian commandant. Division
General Count Giorgio Carlo Calvi di Bergolo. The arrangement
provided that German soldiers were to remain outside Rome, an
open city, except for guards at the telephone exchange, the
German embassy, and the EIAR radio transmitter.

This armistice was violated almost before the ink of the
signatures was dry. Lorries of German soldiers rolled into the
metropolis, the principal points were placed under guard, and
sentries were stationed at the approaches to Vatican City. The
purpose of the pact, apparently, was to make it possible for the
Germans to hand orders to Calvi di Bergolo to be reissued in his
own name. This would avoid having all prohibitions blamed on
the Nazi command. To the north, similar arrangements were
made by General Vittorio Ruggero for the surrender of the
Milan area. The situation was stated quite concisely by the
National Fascist radio, broadcasting via Berlin, on September 20.
After denying a rumor that Pope Pius XII had refused to receive
the commander of the southern military zone. Field Marshal
Albert Kesselring, the Fascist radio declared, “Kesselring can be
denied nothing.’^

It was thought expedient by the Germans to allow the forma-
tion at Rome of a giunta of career bureaucrats to carry on the
technical and administrative functions of the various ministries
in the absence of a national government. Accordingly, four days
after the surrender of Rome, a series of such nominations was
published. These new officials were called commissaries and
received no salaries. None of the appointees was a former rank-
ing Fascist.^

^A former prefect, Dr. Gian Giacomo Bellazzi, was named president of
the council of ministers ; Dr. Augusto Rosso, onetime ambassador to
Washington, became commissary for foreign affairs; Dr. Lorenzo LaVia,
ex-prefect of Bergamo, headed the interior ministry. Others picked by
Calvi di Bergolo were : Dr. Enrica Cerulli, Italian Africa ; Dr. Giovanni
Novelli, grace and justice; Dr. Ettore Cambi, finance; Dr. Giuseppe

ESTABLISHMENT OF MUSSOLINI’S NEO-FASCIST STATE 282

In the meantime, the possibility of the formation in Italy of a
national regime along Fascist lines had been given substance by a
Trans-ocean flash, on the evening of September 12, that Nazi para-
troops and men of the Waffen S.S. and Secret Security Service had
just rescued Mussolini from confinement in the mountainous Gran
Sasso area northeast of Rome. Several former associates as well
as his family were said to be with him. On arrival in the
R'Cich, the Duce was alleged to have telephoned his thanks to
Hitler and then retired to rest. The German radio and press
chortled over the escape and promised that Mussolini would soon
place himself at the head of things in occupied Italy.

Mussolini, presumably at Munich, spent the days immediately
following his liberation in resting and catching up on the events
v/hich had taken place since July 25, for the Badoglio jailers had
kept him cut off from all news sources. While Fascist hierarchs
who had escaped the Allies were conferring with Mussolini to
select a capital for the new government on Italian soil, the Ger-
man and Japanese foreign offices found time to state
categorically:

“The Government of the Empire of Japan and the Government
of the Greater German Reich jointly and solemnly declare: the
treachery of Marshal Badoglio’s Government in no way affects
the three power pact which remains in force without any change.

The Government of the Japanese Empire and the Government of
Greater Germany are determined, jointly, with all the measures
at their disposal, to carry on the war to a victorious conclusion.”

Later a Wilhelmstrasse spokesman added: “Let it be under-
stood that the National Fascist government, which has the
support of all militant sections of the Italian people, is determined
to carry on the war at the side of its allies.” It was advertised
that many Blackshirt and some infantry divisions in Greece and
Jugoslavia were taking up arms again in support of Mussolini.

The first proclamations of the National Fascist government
look the form of five orders of the day published over Mussolini’s
name on September 15. These decrees announced: (a) Mussolini’s
assumption of the supreme direction of Fascism, (b) his appoint-
ment of Alessandro Pavolini as temporary secretary of the Na-

Giustini, education; Professor Vittorio Ronchi, agriculture; Luigi Velani,
communcations ; Dr. Ernesto Santoro, industry and commerce ; Paolo
Saltino, public works ; Dr. Amedeo Tosti, popular culture ; Dr. Francesco
Cremonese, foreign currency and exchange ; and Dr. Franco Liguori, war
production. At least two of these men. Rosso and Tosti, had held places
briefly under the Badoglio government. Three days later, September 17,
commissaries for the military ministries were chosen : General Rino
Gambelli, war ; Vice Admiral Emilio Farrari, marine ; and General Pilot
Aldo Urbani, air.

284

JOURNAL OF FLORIDA ACADEMY OF SCIENCES

tional Fascist Party (henceforth to be known as the “Republican
Fascist Party’^), (c) restoration of all former Fascist office-
holders to their old positions, and (d) appeals to the people to
collaborate with the Germans, fight the Anglo-Americans, reform
the Fascist militia, and punish traitors. All Italian soldiers or
ex-soldiers were ordered on the same day to report to the nearest
German commandant. Shortly thereafter. Lieutenant-general
Renato Ricci was named commander-in-chief of the Voluntary
Militia for National Security.

Several more days elapsed with little indication that the
government was anything more than a radio invention of the
Nazis. Except for a D.N.B. broadcast reporting that Mussolini
had released all army officers from their oaths to Victor Emman-
uel, events lagged. Even Mussolini’s whereabouts was not pub-
licly known. The business of government was carried on only at
the provincial and communal levels.

Mussolini’s first radio address after his liberation was made
from Germany on September 18. His voice sounded old and tired.
Omitted were the histrionics of the past. Such odd phrases as
“the radio does not permit long speeches” made the speech seem
weak. The Duce told of his escape from confinement, then urged
his people to war against the Allies. He outlined a four point
program for faithful Fascists: (a) the taking up of weapons
again at the side of Germany and Japan, (b) the reconstruction
of the army with the Fascist militia as nucleus, (c) the elimina-
tion of the traitors of July, and (d) “the establishment of a social
basis on which the State may be erected, supported by the work
of its citizens.” Interesting was this emphasis on social reform:
‘ The State we wish to establish anew shall be national and social,
in the best sense of the word, a Fascist state as it was at its
beginning.”

World reaction to Mussolini’s comments came quickly. Prime
Minister Churchill seemed to express prevailing Allied feeling
when he said to Parliament :

“The escape of Mussolini to Germany, his rescue by paratroops,
and his attempts to form a quisling Government which with Ger-
man bayonets will try to refix the Fascist yoke on the necks of
the Italian people raise, of course, the issue of Italian civil war.

It is necessary in the general interests, as well as in that of Italy,
that all surviving forces of Italian national life should be rallied
around their lawful Government and that the King and Marshal
Badoglio should be supported by whatever liberal and leftwing
elements are capable of making head against the Fascist-quisling
combination and thus of creating conditions which will help to
drive this villainous combination from Italian soil, or better still,
annihilating it on the spot.”

ESTABLISHMENT OF MUSSOLINI’S NEO-FASCIST STATE 285

The Diario Comercial of Tegucigalpa, Honduras, echoed this with
a reference to Mussolini as an “exploded skyrocket.’^

After his radio speech, Mussolini visited Hitler and then de-
parted on the 21st for Italy. Two days later came the listing of
the slate of neo-Fascist cabinet ministers. Mussolini was chief
of government and foreign minister. Marshal Kodolfo Graziani,
out of favor since 1941, received the portfolio of defense. Guido
Buffarini, who supported Mussolini during the Badoglio palatine
revolution in July, was named interior minister.^

In order to give a picture of an Italy with a centralized
Fascist government, broadcasts of the Republican Fascist radio
reported great activity by the new regime : Fascist prefects were
said to be functioning in the principal cities of occupied Italy;
the Fascist Party had been reformed at Genoa ; the new prefect
of the Trentino was ordering the pictures of Mussolini to be put
back in the place of honor in all government offices ; a new cur-
rency tied to the Reichsmark was announced to be in the process
of preparation; and a commission was appointed in Rome to
examine the attitude adopted by members of the Fascist party
during the July crisis.

One of the most surprising actions of the National Fascist
government was the broadcasting of attacks on the Vatican.
This was totally out of keeping with Fascism’s previous program,
for down to 1943 efforts had been made to maintain satisfactory
relations with the papacy. September 20, at 6 :30 p.m., the
National Fascist radio, broadcasting via Berlin, aired an anti-
clerical statement written in the style of Roberto Farinacci :

“The Vatican, with its preaching of pacifism and with its anti-
German sentiments, has disturbed the Catholic conscience of the
Fascist fighters. These centers of sabotage and betrayal will be
eliminated from the new Fascist and Republican Italy. Let not
the policy of the Vatican force us to have recourse to radical
measures. . . . the Catholic Church has had many favors from the
Mussolini regime. ... to this. . . . the Catholic Church replied with
direct and indirect sabotage of the Fascist war, of the racial cam-
paign and of Fascist ethics. ... If it were true — and it is not —
that there exists an incompatibility between the Catholic faith and

^Domenico Giampietro Pellegrini, former treasury undersecretary, be-
came minister of finance; Antonio Tringali-Casanova, Fascist leader who
had supported Mussolini on July 25, was chosen minister of grace and
justice ; Carlo Biggini received the portfolio of education ; Fernando
Mezzasoma, popular culture; Giuseppe Peverelli, public works; Edoardo
Moroni, agriculture ; Silvio Gai, corporative economy ; and Domenico
Arcidiacono, communications. Francesco Maria Barracu was selected
under-secretary to the premier.

286

JOURNAL OF FLORIDA ACADEMY OF SCIENCES

the Fascist faith, and if we are forced to choose between the
Catholic faith and the Fascist faith, we by the side of our German
comrades, would choose the Fascist faith.”

Whether or not the Germans were using the Fascist radio to
say unofficially what they were hesitant about saying openly,
the fact remains that they failed to follow up the original
charges against the Church. On the very next day the Nazi
Transocean news agency denounced as ‘‘pure invention’’ the
Reuters’ report of the radio attack on the Vatican. A Wilhelm-
strasse spokesman was quoted as saying that neither the German
nor the Fascist Republican government knew of any such broad-
cast. A second, though less hostile, denunciation came on the
25th when the Fascist radio complained about Italian ecclesiastics
who were opposed to Fascism. Nor was the Vatican alone in
bearing Fascist wrath. Jews, freemasons, traitorous generals,
industrialists, leftists, and anti-Fascists were condemned along
with the priests.

To reassure skeptical Italians, the neo-Fascist press and radio
gave little play to stories which might bring unfavorable reac-
tions. The Fascists did say, though, on September 19, that Italian
militiamen would be organized and sent to the Russian front to
erase the defeats sustained by the Italian expeditionary force in
the Don Bend at the beginning of 1943.

The capital of the Republican Fascist state was located at
Verona, on the excuse that telegraphic communication with the
rest of Axis Europe would be better there than in Rome. The
Eternal City was also regarded as being “too near the sea.” By
the end of September, most of the new ministers had been
installed in office at Verona.

Mussolini felt obliged at this time to make another public
statement calling on former Fascist legionaries to follow his lead :

“Legionaries ! Once more the Duce calls you. Now it is a
question of life or death. Legionaries of Africa, Spain, Russia,
the Duce knows you will gather around him. It is better to meet
a glorious end on the battlefield than to live as traitors. Legion-
aries ! He who fears death is unworthy to live !”

On the basis of reports from Switzerland, the attempts of the
Fascists to mobilize the militia proved futile. In most places not
one man in ten answered the call. In Domodossola, a town of
6,500 inhabitants, only thirteen men appeared. The rest of the
able-bodied men went into hiding to escape mobilization.

Mussolini’s efforts to obtain diplomatic recognition abroad
succeeded but slowly. Germany, Roumania, Bulgaria, Croatia,
and Slovakia granted quick recognition. The Japanese let it be

ESTABLISHMENT OF MUSSOLINI’S NEO-FASCIST STATE 287

known that appropriate steps would be taken when official
reports had been received from the Japanese ambassador to
Italy and after consultation with the German government. To
speed up recognition from the Nipponese, the Duce saluted the
third anniversary of the Tripartite Pact, September 27, saying
that he deemed it a good sign that his return to Italy coincided
with the anniversary of the Pact, and pledging to maintain that
alliance and wipe out the humiliation of Italy’s collapse.

The Hungarians gave grudging recognition “at Germany’s
request,” on the 29th. It was alleged that in a stormy five-hour
cabinet meeting the Budapest government decided to maintain
relations with Marshal Badoglio. Two hours after the publica-
tion of this news, a strong note from Berlin brought an about
face and Mussolini was recognized. Several days later the puppet
government of Burma followed suit, then ultimately Spain and
Japan. Finland flatly refused to recognize the neo-Fascists.

The first cabinet session took place on September 27. The
government promised to summon a constituent assembly in due
course to draw up a constitution for the state. It was apparently
decided that in propaganda the emphasis should be laid on pre-
senting the regime to the Italians as a genuine government of
the people. While the use of the term democracy was carefully
avoided in all official statements, every effort was made to view
the changes anticipated as a return to primitive Fascist prin-
ciples. Hence the newspaper II Messaggero wrote, “With the
disappearance of the monarchy, the road is clear for the abolition
of all remaining privileges.” For home consumption, stories were
spread that Sicily was to be detached from Italy and turned into
a British strategic base, that thousands of Italians were being
deported to Africa and Russia, and that the Barclay Bank was
engaged in exploitation in Sicily.

As an aftermath of the first cabinet meeting, a decree of
October 2 created special tribunals to try for high treason party
members “guilty of passing to the enemy at the moment of trial.”
This was followed by mass arrests of persons who manifested joy
when the Fascists fell from power. These included senators,
diplomats, army officers, prominent administrators, newspaper
men, and ex-Fascists. Roberto Farinacci and Alessandro Pavolini
particularly promised arrest of all traitors without clemency.

Marshal Graziani was the most active of the cabinet ministers
during the early days of the neo-Fascist government. He held
meetings at Rome and elsewhere of army officers and tried to get
them to serve the Mussolini cause once again.

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JOURNAL OF FLORIDA ACADEMY OF SCIENCES

While Graziani was rebuilding the army, the Germans were
begging for workers from Italy for their factories and recruits
for their armies. Marshal Kesselring appealed in person over the
Kome radio on September 29 for men. He promised that the
enlistees would receive the same pay as German soldiers and,
after a period of training in special camps, enjoy the same rights
as their Nazi friends.

The impressment of workers into the ranks of foreign laborers
in Germany was carried on by the neo-Fascists. The Mussolini
government called for the migration of workers from southern
and central Italy to the northern part of the country, promising
work and decent living conditions; no hint was made that the
workers might be transported to the Reich. A clue to what
awaited the laborers was contained in the threat that criminal
activity would be countered by summary action under the Ger-
mans’ inexorable laws.

The indication that the new National Fascist state was a
functioning entity came with the publication of the oath of
allegiance to the puppet government. Whether anyone could sup-
port the new regime is equivocal ; certainly there must have been
many mental reservations among the neo-Fascist bureaucrats and
army officers who promised: ‘‘I swear to serve and defend the
Italian Social Republic, its institutions and laws, its honor and
territory in peace and in war, if necessary at the cost of the
extreme sacrifice. I swear it before God and those who gave their
lives for the unity, independence and future of the Fatherland.”

* * *

So far, this paper has dwelt on the technical process by which
Mussolini returned to power. Now it remains to evaluate the
results of this temporary rebirth of Fascism. These results may
be divided into two categories, short and long term. Of the im-
mediate consequences, the following should be pointed out: (a)
First of all, the Fascist renascence rallied some diehard Black-
shirt troops to the German cause. These soldiers became available
either for combat duty or for guarding military installations
behind the front lines. Also, valuable equipment, including
some naval units, was prevented from passing to the Allies, (b)
The Italian defection had been a mighty blow both to Nazi pres-
tige and the whole philosophy of dictatorship. The reappearance
of Mussolini helped the Axis to recover face. At the same time
it made possible the propaganda line that the majority of Ital-
ians rejected the surrender brought about through the treachery
of King Victor Emmanuel and Marshal Badoglio. (c) The neo-

ESTABLISHMENT OF MUSSOLINI’S NEO-FASCIST STATE 289

Fascists performed routine administrative functions and kept to
a minimum the numbers of Nazi personnel required to rule the
country. A whole generation of Italians knew no other form of
government than Mussolini’s. It was easier to control such people
by reconstructing the old order than by outright martial law.
Also, jobs were created for deserving Fascists who had been
ousted from their posts by the Badoglio coup d’etat. This helped
to keep them from drifting toward the Allied camp, (d) On the
principle that most Italians would rather receive unpleasant
directives from other Italians than from Germans, the Nazis used
Mussolini to recruit workers for Reich factories, (e) By reestab-
lishing the Fascist state, the Germans kept up the fiction of the
Fascist partner-in-arms, thus giving them a legal lever for regu-
lating Italians abroad and Italian laborers inside Germany, (f)
The Nazis found it to their advantage to use the Fascist press
and radio as sounding boards for statements they did not wish to
make on their own initiative.

In contrast to the foregoing are the broader achievements of
the Germans, (a) The neo-Fascists split Italians into two camps,
those favoring Mussolini and the Nazis, and those backing
Badoglio and the Allies, (b) The Badoglio people, in summoning
Italy to join the Allies, had put much stress on the legitimacy of
the monarchy. The Fascists, who countered by espousing repub-
lican doctrines, succeeded in stirring up much latent republican-
ism among Italians in northern Italy, (c) Through radical
promises, the revived Fascist political machine tried to discredit
in advance any liberal institutions Italy might be given by the
democratic parties. If someday it would be possible to compare
column by column a workable liberal constitution with a paper
charter of radical Fascist reforms, some argument might be made
for the latter program. Parenthetically, Mussolini must have
hoped that a successful comeback would give him a more impres-
sive niche in history than he had earned previously, hence his
willingness to gamble to the last on a German victory.

It remains for the historian to add two other considerations.
Because the Fascists punished many of the July traitors, Italian
courts later were spared the trouble of having to try these ex-
Fascists for war crimes and other offenses. And lastly, the rise
of the National Fascists with their attacks on the middle classes
and the important industrialists, godparents of the original
Fascism, provided a telling argument for the Anglo-Americans.
It showed in clear colors how the Fascist hydra came ultimately
to devour its very progenitors.

THE PECTIN CONTENT OF THE PERSIAN LIMRi

Margaret J. Mustard
University of Miami

During recent years the production of Persian or Tahiti limes
has steadily increased until it has become one of the major indus-
tries of south Florida. A portion of each year’s crop is now being
processed in order to help supply the growing demand for canned
fruit juices. Of the 218,693 boxes of Persian limes produced in
Florida during the fiscal year ending June 30, 1945, 11,908 boxes
were processed. During the months of July and August of this
year alone, 28,609 boxes of limes were sent to the canning plant
(L. G. MacDowell, in lit., 1945). The lime residue resulting from
processing this fruit is, at the present time, being used chiefly as
a source of lime oil (L. G. MacDowell, in lit., 1945). Although
pectin is extracted commercially from some of the other citrus
residues, apparently little information is available on its extrac-
tion from the residue of the Persian lime. Adriano and his
associates (1932) working with the Philippine-grown Tahiti lime
found that the peel of this fruit contains 2.63 percent pectin. The
present investigation was undertaken to determine the quantity
and grade of pectin which can be extracted from the Persian lime
grown in Florida.

Material and Methods

The limes used in this study came from various lots of fruit
delivered to a packing house in south Dade County during the
1945 season. Since each of the lots came from different widely
scattered groves, they were fairly representative of the limes
produced in that area. Each sample consisted of fifty, unwaxed
limes selected at random from lots of either ungraded fruit
referred to as “field run” or from lots of fruit graded as “Number
3’s”. The analyses were run as soon as possible after the fruit
arrived in the laboratory.

A composite sample of juice was extracted from the fifty limes
with an electric reamer, its specific gravity determined, and a
100 ml aliquot transferred to a liter beaker containing 500 ml of
distilled water. Another composite sample was made from the
peel and rag remaining after the juice had been extracted from
each group of fifty limes. Such a sample was composed of small,
triangular sections removed at random from each of the 100

^This investigation was sponsored by the Science Research Council of
the University of Miami.

THE PECTIN CONTENT OF THE PERSIAN LIME

291

pieces of peel and rag. After such a composite sample was weighed,
it w^as blended with 300 ml of distilled water in a Waring Blendor,
the resulting mixture poured into a liter beaker, and 200 ml of
distilled water added. The diluted sample of juice and that of
the peel and rag were each adjusted to a pH of 1.45 with IN HCl
and extracted with constant stirring at 70 degrees C. for one
hour. Myers and Baker (1931:21-32) have previously demon-
strated that these are the optimum temperature and pH condi-
tions for the extraction of pectin from such samples. Due to the
relatively high viscosity of the extracts, it was necessary to dilute
those of the juice to approximately 900 ml and those of the peel
and rag to approximately 1800 ml before attempting to clarify
them by filtration. A small amount of Hyflo Supercel was added
to each of the diluted extracts before filtering it through a large
Buchner funnel containing a previously prepared filter mat.
Each filter mat consisted of two sheets of Reeve Angel No. 230
filter paper covered with a thin layer of the Hyflo Supercel. The
filtered juice and peel and rag extracts were placed in 1000 ml
and 2000 ml volumetric flasks respectively and diluted to volume.

The pectin was determined as true calcium pectate by a
method fundamentally the same as the modification of the Carre’-
Haynes method described by Hinton (1940). One hundred ml
aliquots of the clarified juice extracts and 75 ml aliquots of the
clarified peel and rag extracts were used in these determinations.

The pectin used in the determination of the jelly grade was
obtained by precipitating this material from 600 ml of the
clarified peel and rag extracts with twice that volume of 90%
ethyl alcohol containing 5 ml of 1.0 N HCl per liter. The pre-
cipitated pectin was removed by filtering the mixture through a
piece of fine cotton cloth and squeezing it as free of alcohol as
possible. It was then’ rinsed in two changes of 95% alcohol
followed by one of ethyl ether. After the ether had been allowed
to evaporate at room temperature, the pectin was dried in a
constant temperature oven at 60 degrees C for 16 hours, ground
with a mortar and pestle, and returned to the oven for an addi-
tional 16 hours at the same temperature. This method is essen-
tially the same as that outlined by Myers and Baker (1931:5).
These authors have pointed out that the addition of sufficient
HCl to the alcohol used in the precipitation of the pectin obviates
the construction of jelly strength-pH curves for the various
pectins, since pectins precipitated under these conditions will
have hydrogen ion concentrations that will result in the forma-

292

JOURNAL OF FLORIDA ACADEMY OF SCIENCES

tion of jellies having the greatest strength (1929:17,41 and
1931:6).

Jelly grade^ was determined on the basis of a 65% added
sugar jelly made by first dissolving 0.5 grams of pectin followed
by 50 grams of sugar in 100 ml of distilled water and boiling the
mixture until the weight of the contents of the beaker was 77
grams. As soon as this weight was reached, the contents of the
beaker was quickly poured into a wide mouth bottle which was
immediately stoppered to prevent evaporation. The jellies were
allowed to stand at room temperature for 24 hours before jelly
grade determinations were made using the apparatus and cali-
bration curve described below.

Various pieces of equipment have been used to determine the
strength of jellies. The strength of the jellies here described
was determined with a piece of apparatus similar in principle
at least to the Lipowitz meter (Tschudy, 1943). The apparatus
consists of a vertically supported, sliding rod having the flat
surface of a small, metallic hemisphere attached to its lower end
and a small balance pan mounted on its upper end (Plate 1).
The wide mouth bottles containing the jelly samples were placed
under the lower end of the rod in such a manner that the metallic
hemisphere rested on the center of the surface of the jelly. Small
washers of approximately the same weight were placed on the
pan at the rate of one every two seconds until a sufficient weight
had been added to cause the hemisphere to break through the
surface of the jelly. The total weight supported by the jelly,
including the total weight of the washers plus the weight of the
apparatus, was converted into jelly grade by reference to a
calibration curve (Fig. 1). This curve was constructed by deter-
mining the weight supported by 65% added sugar jellies of
known jelly grade. These jellies were made by the procedure
described above except that various amounts of 150-grade com-
mercial citrus pectin were used instead of the pectin of unknown
grade. The amounts of this pectin used were such that they were
equivalent to 0.5 grams of pectins ranging from 100 to 525 grade.
It was found by constructing a jelly strength-pH curve that
solutions made from this commercial pectin needed no pH adjust-
ment, since the untreated pectin solutions were found to produce
the jellies of greatest strength.

*The jelly grade of a pectin is expressed as the number of parts by
weight of sugar that one part by weight of pectin will cause to gel when
the jelly is prepared according to a standardized procedure. Under such
conditions, 1 gram of 100 grade pectin will gel 100 grams of sugar.

Plate 1 — Apparatus used for determining jelly grade.

WEIGHT SUPPORTED BY JELLY-GRAMS

THE PECTIN CONTENT OF THE PERSIAN LIME

293

Fig. 1 — Curve sliowing the relationship between the weight supported
by a jelly and the jelly grade.

Results

The data obtained as a result of these analyses is presented
in table 1. The percentages of pectin were calculated on the fresh
fruit basis. It should be remembered, as pointed out previously
in this paper, that each composite sample consisted of represen-
tative portions of fifty fruit from each individual lot. Thus the
number of fruit used in obtaining the figures for the average
pectin content and jelly grade varied from 100 to 200 depending
upon the number of lots of a particular grade sampled on that
date.

JOURNAL OF FLORIDA ACADEMY OF SCIENCES

TABLE 1. DATA FOR PECTINS EXTRACTED FROM
PERSIAN LIMES OF SOUTH FLORIDA.

WD

•S ,,

*

^

Description
of Sample

Pectin Content

Jelly

Grade

Ot 'tw

m

w S-I ft

a

(Calcium Pectate)

(65%

Sugar)

o o 02

Avg. Range

Avg.

Range

%

%

7/ 3/45

3

Field run

Peel and rag

2.68

2.60-2.81

411+ **343-5254-

Juice

0.08

0.06-0.11

—

7/ 3/45

2

Number 3’s

Peel and rag

2.69

2.33-3.05

420

388-451

Juice

0.07

0.06-0.08

—

7/17/45

4

Field run

Peel and rag

2.93

2.84-3.17

338

259-392

Juice

0.06

0.02-0.15

—

7/17/45

2

Number 3’s

Peel and rag

3.18

3.03-3.32

373

341-404

Juice

0.11

0.05-0.16

—

7/31/45

3

Field run

Peel and rag

2.83

2.23-3.23

375

370-378

Juice

0.03

0.03-0.03

—

7/31/45

2

Number 3’s

Peel and rag

3.19

3.17-3.21

335

264-405

Juice

0.08

0.07-0.09

—

8/14/45

4

Field run

Peel and rag

3.11

2.82-3.38

427+

336-525+

Juice

0.05

0.03-0.07

—

8/14/45

2

Number 3’s

Peel and rag

3.10

3.07-3.12

358

336-380

Juice

0.15

0.15-0.15

—

♦Each composite sample consisted of representative portions of each
of the fifty fruit from a respective lot.

**(-!-) Indicates that one of the jellies had a higher grade than 525
which was the upper limit of the calibration curve.

The data do not show any consistent differences in the
quantity or quality of pectin contained in the different grades of
fruit. It is apparent that a good yield of pectin of exceptionally
high grade can be extracted from the peel and rag of either “field
run” or “Number 3” limes. The pectins, precipitated from the
extracts with alcohol and used in the jelly grade determinations,
were almost a true white and compared favorably in appearance
with a sample of commercial 150-grade citrus pectin. No attempt
was made to determine the grade of the small amount of pectin
contained in the juice extracts. Due to the rather limited nature

THE PECTIN CONTENT OF THE PERSIAN LIME

295

of this investigation,^ no definite conclusion can be reached with
regard to any seasonal variation that may exist in the pectin con-
tent of these fruit.

Conclusion

It is obvious from the results of this preliminary investigation
that the Persian lime is an excellent source of pectin. In view of
the diversified uses of pectin and its derivatives in the fields of
food, industry, and medicine, it is planned to undertake a more
extensive investigation of the possible utilization of lime residue
and cull fruit as an additional source of these products.

Acknowledgments

The author wishes to acknowledge her indebtedness to those
members of the Chemistry and Botany Departments of the Uni-
versity of Miami who offered many helpful suggestions during the
course of this study. Acknowledgment is also made to Florida Lime
and Avocado Growers at Princeton, Florida who supplied the
fruit used in this investigation.

REFERENCES

Adriano, F. T., H. L. Ylizarde, and E. Villanueva

1932. The pectin content of some Philippine fruits. The
Philippine Jour, of Agr., Ill (4) : 273-279.

Hinton, C. L.

1940. Fruit pectins. Their chemical behavior and jellying
properties. Depi. of Sci. and Ind. Bes. (British) Food
Invest. Special Report No. 48. (New York: Chemical Pub-
lishing Co.) : 7-13.

Myers, Philip B. and George L. Baker

1929. VI. The role of pectin. 2. The extraction of pectin
from pectic materials. TJniv. of Delaware Agr. Exp. Sta.
Bull. No. 160. Tech. No. 10: 17, 41.

1931. VII. The role of pectin. 3. Effect of temperature upon
the extraction of pectin. TJniv. of Delaware Agr. Exp.
Sta. Bull. No. 168. Tech. No. 12 : 5-6, 21-32, 44.

Tschudy, Robert H. and Marston C. Sargent

1943. Agar-bearing seaweeds at La Jolla, California, Science,
97 (2508) : 89-90.

*Tlie hurricane which recently swept through this area caused so much
damage to the lime groves that it was impossible to continue the
investigation this year.

FACTORS AFFECTING THE GROWTH AND DISTRIBUTION
OF MYXOPHYCEAE IN FLORIDA

Melvin A. Brannon
University of Florida

This paper reports the study of some physical, chemical and
biological factors affecting the growth and distribution of Myxo-
phyceae collected in three closely related sinks. These sinks are
located in a suburban area of Gainesville, Florida. They form an
approximate right-angled triangle. Sink I, located at the southwest
corner of the triangle, is 450 feet from Sink II at the northwest
corner. Sink II is 750 feet from Sink III at the southeast comer,
and Sink III is 550 feet from Sink I (Fig. 1.).

Fig. 1 — Showing the relation of Sinks I, II, HI and the dimensions
of the right angle triangle formed by their locations.

During a ten year interval, the average annual rainfall in this
area was 48.90 inches.

MYXOPHYCEAE IN FLORIDA

297

Table I. Showing Monthly Rainfall in Inches During the Years 1941-1943

1941

1942

1943

January

3.51

4.04

1.45

February

3.02

4.54

0.12

March

2.27

7.25

2.77

April

3.71

0.52

2.86

May

1.77

0.54

4.94

June

6.57

9.31

5.70

July

5.76

2.79

6.50

August

6.12

5.08

8.07

September

3.15

5.88

5.41

October

15.78

2.21

0.26

November

2.90

0.39

0.40

December

6.24

4.76

2.43

TOTAL

60.80

47.31

40.91

These records exhibit pronounced monthly and annual varia-
tion in precipitation. During the first eight months of 1941 the
precipitation was normal. The water supply in the sinks was
favorable for plant growth. However, very few Myxophyceae were
collected. In September a single genus and species were found in
Sink I, and none in Sinl^s II and III. In October there was an ex-
ceptional rainfall of 15.78 inches. This affected several physical
and chemical factors, but no noticeable increase in population of
algae, and no increase of genera and species were observed.

In 1942 the monthly rainfall was very irregular. During three
months of the year it was less than an inch per month. Such
irregular precipitation causes changes in concentration of solutes,
osmotic pressure, and pH. It was expected that some correlation
between these changing physical and chemical factors and the
number of genera and species of Myxophyceae collected might be
found. No correlation could be determined. During the greater
portion of this 15 months study the water in each sink covered 1/2
acre of area. The water level varied 5 feet in 1941 and 4 feet in
1942.

The following Myxophyceae were collected during the period
from September 1, 1941 to December 1, 1942. The dates of collec-
tion of each species reported are indicated. The greatest number
of species was collected in October of 1942.

Sink I

Lynghya Diguetii Gom 9-17-41

11-26-41

Lynghya putealis Gom 11-13-41

Chlorococcum humicola Nag 2-14-42

Anacystis marginata Menegh 6-13-42

Anacystis rupestris Drouet 1- 5-42

298

JOURNAL OF FLORIDA ACADEMY OF SCIENCES

Sink I — Continued

Aphanocapsa Orevillei (Bark.) Rabenh 6-13-42

8- 5-42

Aphanocapsa Richteriana Hiron 6-13-42

Oscillatoria tenue var. natans Gom 1- 5-42

Lynghya Patrickiana Drouet 8- 5-42

10- 6-42

Lyngbya Taylorii Drouet and Strickl 10- 6-42

Lyngbya aestuarii Gom 10- 6-42

10- 21-42

Lyngbya versicolor Gom 10- 6-42

11- 10-42

Phormidium autumnale Gom 11-10-42

Nostoc Hederulae B. and F 4> 8-42

6-13-42

Nostoc humifursum B. and F 10-20-42

Alosira implexa B. and F 8- 5-42

10- 6-42

Fremyella diplosiphon (B, and F.) Drouet 2-14-42

Scytonema coatile B. and F 8- 5-42

10- 6-42

11 Genera — 18 Species
Sink II

Nostoc Muscorum B. and F 10-10-41

10-21-41

10-25-41

10-26-41

8-24-42

Calothrix parietina B. and F 11-25-41

Plectonerna Nostocorum Gom 11-25-41

10- 6-42

Oscillatoria anguina Gom 10- 6-42

Oscillatoria chlorina Gom 10- 6-42

Oscillatoria princeps Gom 10- 6-42

Oscillatoria tenue var. natans Gom 10- 6-42

Microcoleus lacustris Gom 8-24-42

Anabaena oscillarioides B. and F 4- 8-42

Scytonema ocellatum B. and F 8-24-42

Fischerella ambigua (B. and F.) Gom 10- 6-42

8 Genera — 11 Species

Sink III

Polycystis aeruginosa Kutz 10-23-41

Anabaena circinalis B. and F 10- 9-41

3-26-42

3-27-42

3-29-42

Anabaena flos-aquae B. and F 3-26-42

3-27-42

3-29-42

Oscillatoria Agardhii Gom 6-13-42

6-24-42

6-30-42

3 Genera — 4 Species

MYXOPHYCEAE IN FLORIDA

299

Distribution

These lists show selectivity and individuality in habitat of the
Myxophyeeae reported in this study. Only four of twenty-four
genera were found duplicated in two sinks — ( Oscillatoria, Nostoc
and Scytonema in Sinks I and II, and Anahaena in II and III).
Also only one species was duplicated in two sinks — ( Oscillatoria
tenue var. natans in Sinl^s I and II).

Figure 1 shows the intimate relation of the three sinks. When
the animal agents associated with these sinks (turtles, herons,
domestic ducks, dogs and human beings) are considered, it would
seem that there should have been more inter-sink distribution and
duplication than was found. Since Myxophyeeae have no means
of moving from sink to sink by their own power, but must depend
wholly on biotic agents, there is, of course, a large element of
chance in their distribution, even in such closely related sinks as
I, II, and III. The problem called for an examination and appraisal
of some of the physical, chemical and biological factors affecting
these algae in order to find a solution.

The factors considered were light, heat, osmosis, and radioac-
tivity ; mineral nutrients, oxygen, carbon dioxide and pH ; over-
crowding of living forms, and possible excretion of growth
substances which might retard or accelerate growth.

Sink I is located in an open area which is free from surrounding
shrubs and trees. In the summer Lotus leaves and Panicum grass
form a shade border ten feet wide around the outer zone of the
sink. This growth cuts the light and lowers the temperature
slightly. The light and heat factors are very high in Sink I in
the summer. They are exceedingly favorable for photosynthesis
and growth and reproduction of Myxophyeeae. In contrast Sinks
II and III are closely surrounded by shrubs and trees. Also in
Sink II a dense carpet of Spirodela pohjrhiza developed over the
major portion of the water area. These timbered borders and
carpet seriously affected both light and heat. The result was
registered, to some extent, in the reduction of genera and species
of Myxophyeeae in II and III.

Osmosis was somewhat higher in Sink III than II and I. The
difference in this factor, however, did not affect the growth and
distribution of the algae to any measurable degree.

Radioactivity was suggested as a possible factor in this prob-
lem. The results secured from precision tests of water samples
from each sink answered this suggestion in the negative.

300

JOURNAL OF FLORIDA ACADEMY OF SCIENCES

Chemical analyses of the water in each sink gave the following
results ;

Bicarbonate Alkalinity

Sink I

Sink II

Sink III

(Calc, as CaCos

Insoluble Residue

61.0

32.5

72.8

Sio plus BaS04, etc.

3.6

6.8

4.0

R2O3 meaning FeaOs+AlaOg

8.4

4.4

3.2

CaO determined gravimetrically

41.6

27.8

36.0

Total p.p.m. as reported (analysis)

114.6

71.5

116.0

Free oxygen was present in abundance for respiration of
algae in all sinks.

Ample carbon dioxide was secured from the Bicarbonates for
the photosynthesis of the algae.

The mineral nutrients, calcium, iron and phosphates were in
adequate quantities for the normal metabolism of all algae
and higher plants present in the sinks.

The factor of pH was studied carefully in the case of each
sink. Many collections of water were made during the time
this study was made. The minimum and maximum readings
were :

Sink I Sink II Sink III

pH Min 6.92 6.26 6.92

Max 8.75 7.80 9.15

This factor varies when the CO2 varies from high in the morn-
ing, after the low light of night, to a lower level in the sun-
light and resulting photosynthesis. It varies with changing
concentration of the solutes, which are acid, base or salt, in
sink water. The pH factor is such a dominant agent in the
metabolism of the living organism that it must have great
importance in growth and multiplication of Myxophyceae.
Pasteur, who first recognized its significance in all living
forms, affirmed that “each plant has its optimum and mini-
mum concentration of pH for growth. Not only different
species, but different races of the same plant show different
requirements with reference to pH. ’ ’

Bonner (1934) pointed out that the magnitude of growth sub-
stance effects is directly related to the hydrogen-ion concentration
of the medium in which growth substance is applied. He concluded
from his study with Avena coleoptile that the growth substance is
converted from the form of an inactive salt to an active, non-
dissociated form in the presence of acid buffers.

MYXOPHYCEAE IN FLORIDA

301

Marmer (1937) also found that the effect of growth substance
on the growth of wheat seedlings is related to the pH of the applied
solution. She reported that indole-3-acetic acid is 15,000 times as
effective at pH 4.6 as at pH 7.5, and that indole-butyric acid is 10
times as effective, and indole-propionic acid is 20 times as effective
at these respective levels of pH.

Albaum, Kaiser, and Nestler (1937) found that the penetration
of indole-3-acetic acid into cells of Nitella takes place more rapidly
at pH 3.65 than at pH 7.94. On the basis of their results they con-
cluded that the hydrogen ion concentration affects the degree of
dissociation of molecules of growth substance and that the heter-
auxin enters cells of Nitella in molecular form.

All of these research workers secured results in complete agree-
ment with Pasteur’s appraisal of pH action. He stated that “one
might as well expect to get the same chemical reactions at different
levels of pH as to get the same chemical reactions at different
degrees of temperature. ’ ’

In view of the importance and power of hydrogen-ions, and the
greatly increased biological-chemical action when optimum pH
levels are employed, it is suggested that the hydrogen-ion may
have a large effect in growth of Myxophyceae growing in sinks I,
II, III. Other factors are involved, indubitably, in causation of the
variables reported in this study — such as only one species out of
33 appearing in 2 sinks, and only four genera out of 22 being
found in a second sink.

The biological factors of crowding and secretion of accelerating
and retarding substances were observed in the genus Anahaena. On
the 26th of March 1942 there was an excessive growth of Anahaena
circinalis and A. flosaquae in Sink III. The precipitation during
the preceeding 7 months had been over 40 inches. The temperature
was 24° C, and the pH was 8.87. These were very favorable for
the rapid development of Anahaena. A green, cream-like mass
covered the water surface, and there were over 100 million plants
p.c.c. This condition reached its maximum state within 96 hours.
Then there was decline in numbers and a gradual disappearance
of Anahaena. The excretion of oil caused a disagreeable odor about
the entire sink during the period of maximum growth. This seemed
to be associated with decline of growth and disappearance of the
alga. This was the only example of the accelerating and retarding
effects of crowding and excretion of toxic products by any of the
Myxophyceae reported in this study.

The variable number of genera and species of Myxophyceae
growing in the closely associated sinks I, II, III, presents a paral-

302

JOURNAL OF FLORIDA ACADEMY OF SCIENCES

lei which has been observed by algologists in other parts of Florida
and the world. It is interesting to learn from L. H. Tiffany
(1944:99) that he had similar experiences with collections of
Oedogoniales. He states that ‘‘A pond scarcely more than an acre
in area located in a cypress “strand” just south of Arcadia, Flori-
da, yielded thirty-one species and two varieties of Oedogonium and
Bulhochaete. This large number was not equaled anywhere else in
the state, although most of the ponds in cypress swamps were
highly productive. It is very difficult to understand the diversity
of yield in what appear to be very similar bodies of water. Nearly
every algologist has had the experience of discovering a pond, or
other habitat, in a given area unusually rich in species when com-
pared with apparently similar habitats in the same area. Until
biological investigations can be carried out in different localities
over a period of years, the relations of environmental factors to
algal productivity as well as the accident of introduction through
carrier agents such as birds can be surmised but not accurately
gauged. ’ ’

After discussing dormancy, permanency of habitat, proper en-
vironmental conditions, and the accident of dispersal or rise of
species by some heritable variation, he (Tiffany, 1944:100) con-
cluded that “these intriguing problems cannot all be solved in a
day or a year or even a lifetime, but the patient accumulation of
ecological, physiological, morphological, and genetical data on the
Oedogoniales will some day make it possible for us to see through
much of the haze that now surrounds the explanation for the dis-
tribution of the members of this algal group.”

Summary

In this study of factors affecting growth and distribution of
Myxophyceae collected in Sinks I, II, and III, a total of 22 genera
and 33 species were identified. Four physical, four chemical and
two biological factors were considered relative to growth and dis-
tribution. Only one of the ten factors mentioned seemed to have the
rank of a limiting factor in growth and multiplication of units,
and thus indirectly influenced distribution by reason of increasing
population. This factor was the hydrogen-ion. This conclusion was
supported by evidence that the magnitude of growth in higher
plants was definitely due to the effect of the hydrogen-ion.

Acknowledgements

I wish to acknowledge, with much appreciation, assistance
received from the following scientists: Professor J. R. Watson for
Gainesville, Florida 1941-42 and 43 precipitation records; Dr. R.

MYXOPHYCEAB IN FLORIDA

303

A. Carrigan for pH determinations ; Dr. Fred H. Heath for chemi-
cal analyses ; Drs. Arthur A. Bless and Cyril L. Comar for radio-
activity studies of material collected in Sinks I, II, and III ; and
Dr. Francis Drouet, Chicago Museum of Natural History, for
precision studies and determination of the Myxophyceae listed in
this paper.

Literature Cited

Albaum, H. G., S. Kaiser, and H. A. Nestler.

1937. The Relation of Hydrogen-ion Concentration to the
Penetration of Indole-3-acetic Acid into Nitella Cells.
Amer. Jour, of Bot., 24 : 513-518.

Bonner, J.

193^ The Action of the Plant Growth Hormone.

Jour. Gen. Physiology , 17 : 63-76.

Marmer, D. R.

1937. Growth of Wheat Seedlings in Solutions Containing
Chemical Growth Substances. Amer. Jour. Bot., 24 :
139-145.

Tiffany, L. H.

1944. The Oedogoniales of Florida.

Amer. Midi. Nat., 32: 98-136.

THE CRICKET-FROG OF PENINSULAR FLORIDA
M. Graham Netting and Coleman J. Goin
Carnegie Museum and University of Florida

Field studies in the southeastern states and laboratory examina-
tion of large series of freshly preserved specimens have convinced
us that the cricket-frogs of peninsular Florida comprise a recog-
nizable, homogeneous population. For this form the following
name is available:

Acris gryllus dorsalis (Harlan)

(Plate 1, upper fig.)

Florida Cricket-prog

Rana dorsalis Harlan, Journ. Acad. Nat. Sci. Philadelphia, ser.
1, 5 : 340, January, 1827.

Diagnosis

A cricket-frog with two distinct dark postfemoral stripes pres-
ent ; no anal warts ; toes very slender and delicate ; size small (adult
females seldom exceeding 20 mm in snout-to-vent length). The
thigh patterns and anal wartiness of dorsalis, gryllus, and crepi-
tans are illustrated upon the accompanying plate.

Type Locality

As more than one form of Acris occurs in Florida, we have
checked the itineraries of collectors who visited Florida prior to
1827, in an attempt to find the most likely source of the specimens
which Harlan used in describing dorsalis. Fortunately, this was
before many herpetological explorations of the State had been
made, and it appears probable that Harlan’s specimens were ob-
tained by one of two parties.’

In 1818, Thomas Say, in company with William Maclure (then
President of the Philadelphia Academy), George Ord and T. R.
Peale, ascended the St. John’s River to ‘‘about 100 miles from its
mouth” (as far as Picolata in what is now St. John’s County),
seeking “subjects of Nat. Hist, of which the acquisition was the
sole object of our undertaking” (see Fox, 1901: 235). In 1822,
according to Vignoles (1823: 67), Captain John Le Conte ascended
the St. John’s to about the same point that John Bartram had
reached in 1766. Dr. Francis Harper informs us that this was
about the latitude of Titusville. We do not know where or how
much Le Conte collected on this trip, but it may be significant
that Carr (1938: 105) considers that the specimens described by
Le Conte from the St. John’s as Testudo floridana (=Pseudemys
/. floridana) were probably “collected in the lower (northern)
reaches of the river. ’ ’

304

Plate 1.

Miss Mary Cleeves, del.

Typical postfemoral patterns of Acris. x8.

Upper. Acris g. dorsalis. CM no. 17123, Fla., Alachua Co., 1/2
mile east of Gainesville.

Center. Acris g. gryllus. CM no. 16845a, Ga., Liberty Co.,
Riceboro.

Lower. Acris crepitans. CM no. ISOOa, Mich., Washtenaw Co.,
Ann Arbor.

THE CRICKET-FROG OP PENINSULAR FLORIDA

305

So far as we know, these were the only two major herpetological
collecting expeditions made to Florida prior to Harlan’s descrip-
tion of dorsalis in 1827. Dr. Harper informs us that he believes,
on the basis of his investigations of early biological explorations
in Florida, that the material used by Harlan probably was col-
lected on one of these two trips.

We have specimens of Acris collected on the St. John’s River,
in St. John’s County, by the junior author, which are typical of
dorsalis as herein defined. We, therefore, restrict the type locality
of Bana dorsalis Harlan to the lower (northern) one hundred miles
of the St. John’s River.

Description

Harlan’s description, although brief, is very much to the point
and there appears to be no doubt that he had specimens of the
peninsular form at hand. Dunn (1938: 154) states that he has
been unable to locate the types of dorsalis; hence decision as to the
applicability of Harlan’s name must be made on the basis of char-
acters used in his description. This is quoted in full:

Char. — Alove fuscous, smooth, with a broad, white, longitudinal
vertebral band, bifurcating anteriorly, and extending over each
eye : snout above, pale or whitish : beneath white : throat and inner
part of the thighs freckled : buttocks white, with two brownish
transverse lines : a white line on the side of the neck, extending
from the eye to the scapula.

Length of the body 8/10 of an inch ; of the legs 1-1/2 inches. ‘
This measurement being taken from the largest of seven specimens.

Inhabits Florida. Specimens in the Cabinet of the A. N. S.

Of the two heretofore recognized forms of Acris, gryllus and
crepitans, only the former need be considered in connection with
this description, for crepitans would not be described by any care-
ful observer as having ‘‘buttocks white with two brownish trans-
verse lines”; nor does it inhabit the southeastern lowlands. Occa-
sional southern specimens of gryllus do have such a thigh pattern,
but the fact that Harlan redescribes gryllus very accurately on
the same page indicates that he was well acquainted with this
form. Furthermore, many of our specimens of dorsalis display
exactly the dorsal pattern mentioned by Harlan, namely, ‘ ‘ a broad,
white longitudinal vertebral band, bifurcating anteriorly, and ex-
tending over each eye ’ ’ ; the latter portion of this statement is the
most important, for specimens of gryllus rarely exhibit an anterior
bifurcation of the dorsal stripe; in gryllus this stripe usually be-
gins at the apex of the postocular triangle. Furthermore, dorsalis
does not exhibit the elongate dorsal warts so frequently seen in
gryllus, although many specimens have the dorsum well covered

306

JOURNAL OF FLORIDA ACADEMY OF SCIENCES

with small rounded warts; the size mentioned (.8 inch = 20 mm)
corresponds accurately with the measurements of a large number
of dorsalis and is too small for the largest specimen in almost any
series of adult gryllus selected at random.

Variation

The typical pattern of the posterier thigh of dorsalis consists
of two longitudinal white stripes and two longitudinal brown
stripes. When the thigh is viewed from the rear, the stripes from
the dorsal to the ventral surface are as follows: 1) A clear white
stripe bordering the colored dorsal surface of the thigh and very
well defined along this border because both the dorsal ground color
and the superimposed spots are generally darker in dorsalis than
in gryllus; both edges of this stripe are usually straighter than in
gryllus, the stripe is usually broader, and it approaches the vent
more closely at its proximal end than it does in gryllus. 2 ) A dark
brown stripe beneath the superior white stripe, extending from the
vent to the knee, usually narrower than the same stripe in gryllus,
more straight-edged above and below, and frequently narrower
than the white stripes which border it. 3) A second or inferior
white stripe which is usually equally as distinct as the upper white
stripe. The two white stripes vary considerably in width ; they
may be similar in width, the upper may be the broader, or the
lower may be the broader, but, in any event, they appear to have
been widened at the expense of the brown stripe which they en-
close. Harlan’s description of the buttocks as white with two
transverse [= longitudinal] brownish lines conveys the correct
impression. 4) A light brown stripe beginning immediately below
the vent and extending diagonally so that its distal end is always
on the ventral surface of the thigh and sometimes (depending upon
preservation) the entire stripe is ventral in position. This stripe
is rarely as dark as the superior brown stripe, and it is generally
uniform in color from edge to edge, not browner at the margins as
in those few gryllus which display a similar stripe. The inferior
brown stripe is almost always visible from behind in dorsalis and
is always a definite stripe, whereas the most frequent pattern in
gryllus is a general suffusion of brown below the inferior white
stripe, resulting in a triangular dark area which lies immediately
below the vent and which reaches a point beneath the knee.

The last mentioned characteristic offers the best means of sepa-
rating gryllus and dorsalis, but it is not invariably satisfactory.
For example, two of a series of eleven topotypes of gryllus have
clearly defined inferior brown stripes which are diagonal, but
these are the darkest specimens in the series and the white stripes

THE CRICKET-FROG OF PENINSULAR FLORIDA

307

are both narrower and less sharply demarcated than in dorsalis.
Such specimens of gryllus with an excess of dark pig^ment concen-
trated into a stripe have much more heavily marked thighs when
viewed from beneath than do specimens of dorsalis. It must be
noted that the distinctness of the thigh pattern in Atlantic Coast
gryllus increases as latitude decreases. Virginia specimens show
little resemblance to dorsalis, Riceboro topotypes occasionally ap-
proximate dorsalis in thigh pattern although their adult size is
larger, and southern Georgia specimens are the most difficult of
all to distinguish from dorsalis.

Preserved specimens of dorsalis may or may not have a brown
triangle on the head ; this triangle may be completely bordered by
white, it may be bordered on the sides only, or it may be without
light edging. The mid-dorsal stripe may be narrow and white,
broad and light brown (sometimes green in life), or absent. The
pattern of the back may consist of an anterior pair of blotches
which resemble reversed parentheses, followed by a posterior pair
of diagonal club-shaped spots ; or the two spots on each side may be
confluent with distinct lobes directed laterally ; or a single pair of
curved spots may be present, in which case the elongate spot on
each side is rarely as much broadened throughout its length as in
gryllus. A white line from the eye to the shoulder is almost invari-
ably present ; the dorsal surfaces of the thighs are marked with
narrow bars or blotches ; the belly is immaculate or lightly freckled
anteriorly; the throat ranges from a heavily spotted condition in
some males to an immaculate condition in a few specimens.

The amount of webbing is highly variable even in a series of
specimens collected at the same time and place, and apparently
cannot be correlated with sex. The web is always broadly attached
to the base and sometimes to the middle of the penultimate phalanx
of the fourth toe and extends along this toe as a narrow margin to
the disc; it is always broadly attached as far as the base of the
ultimate phalanx of the fifth toe and sometimes to the disc; simi-
larly, it is always broadly attached at the base of the ultimate
phalanx of the third toe, and sometimes beyond the middle of this
phalanx. Describing webbing on the basis of the number of joints
free is not wholly satisfactory in this genus ; crepitans has the most
completely webbed feet and it also has by far the largest feet, so
that when the toes are spread there is a very impressive amount
of web. The feet of gryllus are smaller and appear less fully
webbed than those of crepitans. The trend toward narrower feet
continues in dorsalis, which has toes that are slightly more slender

308

JOURNAL OF FLORIDA ACADEMY OF SCIENCES

than those of gryllus and do not spread apart so widely, so that the
foot appears to have less web. In spite of this, no constant differ-
ence in point of attachment of the web on various toes has been
noticed in comparing dorsalis and gryllus.

A. g. dorsalis appears to be the smallest form in the genus.
Thus, 146 specimens from peninsular Florida range from 13 to 21
mm and average 17.3 mm in snout-to-vent length. In dorsalis the
heel of the extended hind leg generally reaches beyond the snout.

Habits

The junior author, who is well acquainted with dorsalis in the
field, first became convinced that it differs from the cricket-frog of
West Florida when he noted differences in the behavior of the two
populations. In endeavoring to escape capture, dorsalis proceeds
by a number of short leaps with frequent changes of direction,
whereas gryllus in West Florida often leaps as much as five or six
feet and maintains a relatively straight course. In addition, dorsalis
exhibits a greater tendency to hide under concealing bits of vege-
tation either in the water following a dive, or upon land after a
few short hops; under similar circumstances gryllus may come to
rest upon the open beach or upon a grass stem in full view until
the collector approaches sufficiently close to stimulate the frog into
making another long leap.

On April 17, 1939, at a small pond about three miles east of
Gainesville, the junior author observed dorsalis tadpoles feeding
upon free-swimming colonial rotifers (Conochilusf). The tadpoles,
at subtransformation stage, were numerous in the pond. Individ-
uals were observed to swim slowly up to a colony of rotifers and
then suck the entire colony into the mouth. In some instances the
colonies were too large to be swallowed and after a few futile at-
tempts the tadpole would desist and swim off in search of a colony
of smaller size.

Range

We have seen specimens of A. g. dorsalis from the following
Florida counties: Alachua, Broward, Clay, Dade, Duval, Hills-
borough, Lake, Levy, Marion, Polk, Putnam, Sarasota, Seminole,
St. John’s, and Volusia. A series of nine specimens from near St.
Marys, Camden County, Georgia, and a single specimen from five
miles north of Yulee, Nassau County, Florida, are, in most respects,
intermediate between gryllus and dorsalis. Every variation in fe-
moral pattern from that of gryllus to that of dorsalis is exhibited
by these specimens, but their patterns average somewhat closer to

THE CRICKET-FROG OF PENINSULAR FLORIDA

309

that of dorsalis. On the other hand, in body size and in the lack of
distinct dorsal stripes they approximate gryllus more closely. One
series of 27 specimens from Leon County, Florida, includes a num-
ber of adults which exhibit a good dorsalis thigh pattern, but these
are large in size and extremely dark dorsally. The range of A. g.
dorsalis y then, may be stated as from Duval and Jefferson counties,
Florida, south throughout the peninsula. Typical gryllus, as we
understand it, ranges from about Dismal Swamp, Virginia, south-
ward along the Atlantic Coastal Plain to about the Florida-Georgia
boundary, where it intergrades with dorsalis. Specimens which
differ in certain respects from typical gryllus, but which are best
retained under this name at present, range along the Gulf Coastal
Plain from Leon County, Florida, to New Orleans.

Acknowledgments

We are particularly indebted to Dr. Francis Harper for infor-
mation concerning early explorations in Florida; to Mr. Clifford
H. Pope for collecting for us a series of topotypes of gryllus; and
to Mr. Percy Viosca, Jr., for frequent assistance throughout the
course of the study. Prof. T. H. Hubbell, Dr. A. F. Carr, Jr., and
Dr. Horton H. Hobbs, all of the Department of Biology, University
of Florida, have aided us considerably in collecting specimens in
certain critical areas, for which we extend our thanks. To the
following persons and to their respective institutions we are in-
debted for the loan of material or for permission to examine
specimens : Dr. Doris M. Cochran, United States National Museum ;
Mrs. Helen T. Gaige, Museum of Zoology, University of Michigan ;
Dr. Thomas Barbour, Museum of Comparative Zoology; Dr. E. K.
Dunn, Academy of Natural Sciences, Philadelphia; Mr. Karl P.
Schmidt and Mr. Clifford H. Pope, Chicago Natural History
Museum; and Mr. C. M. Bogert, American Museum of Natural
History.

The Carnegie Museum has generously paid for the plate which
accompanies this article.

Literature Cited
Carr, Archie Fairly, Jr.

1938. A new subspecies of Pseudemys floridana, with notes
on the floridana complex. Copeia, 1938 (3) : 105-109.

Dunn, Emmett Reid

1938. Notes on frogs of the genus Acris. Proc. Acad. Nat.
Sci. Philadelphia, 90: 153-154.

310

JOURNAL OF FLORIDA ACADEMY OF SCIENCES

Fox, William J.

1901-02. Letters from Thomas Say to John F. Melsheimer,
1816-1825. I-XI. Entomological Neim, 11: 110-113, 138-
141, 173-177, 203-205, 233-236, 281-283, 314-316; 12:
9-11, 38-40.

Harlan, Richard

1827. Genera of North American Reptilia, and a synopsis of
the species.

Journ. Acad. Nat. Sci. Philadelphia, ser. 1, 5: 317-372.
ViGNOLES, Charles

1823. Observations upon the Flondas. New York. 197 pp.

I

Fig. 1 — Ocala Chamber of Commerce Building constructed from limerock concrete.

i

1

Pig. 3 — Poured limerock concrete construction (residence built by
Mr. B. F. Williamson in Gainesville, 1929).

2 — The Gainesville Livestock Market Office Building constructed
with limerock concrete masonry units.

Fig.

PROPERTIES OF LIMEROCK CONCRETE
Mack Tyner

Florida Engineering and Industrial Experiment Station
Gainesville, Florida

Two kinds of limestone occur in Florida ; the hard variety and
the soft variety known locally as limerock. The amount of hard
limestone available is small compared to the total amount of soft
rock, hence the experimental work described here was concerned
solely with use of the soft variety. This limerock is found in
abundant quantities in the north-central and central parts of the
state, extending in the west to the Gulf Coast. Limerock is a
soft and friable high calcium limestone of white to cream color
made up of marine fossil remains laid down during the Eocene
Age. It is obtained by open pit mining and is generally crushed
before use. Since the limerock contains no clay or organic material,
washing or other processing of the natural material is not
necessary.

The most extensive uses of limerock have been as a sub-base
for highways and as a concrete aggregate. It offers unusual prop-
erties for road building such as high stabilization values, low cost,
local availability, and ability to be reworked. For use as a con-
crete aggregate it is cheap, available, and produces a reasonably
strong product in an economical mix. Much limerock is being
used as aggregate in the manufacture of concrete masonry units.
Numerous buildings and pavements have been constructed using
monolithic limerock concrete and limerock concrete masonry units
(Figs. 1 and 2). These constructions show excellent resistance to
the weather and, in fact, weathering brings out the pleasing white
to cream color of the limerock. Figure 3 shows an all concrete
residence of poured limerock concrete constructed in Gainesville
in 1929 by Mr. B. F. Williamson. Even the roof structure is lime-
rock concrete. This residence, according to the owner, is satisfac-
tory in every way.

The newest field of application of limerock concrete is in the
construction of concrete highways. In the fall of 1944, the State
Road Department, in cooperation with the Limerock Association
of Florida and with the advice of the University of Florida Engi-
neering and Industrial Experiment Station, constructed 4500
lineal feet of experimental limerock concrete road just north of
Gainesville on US 441. In this construction three different mixes

311

312 JOURNAL OF FLORIDA ACADEMY OF SCIENCES

s

were used in three different cross sections, thus giving nine differ-
ent concrete sections which will show the suitability of limerock
concrete for highways in Florida. At the present time every section
is completely satisfactory.

Strength of Limerock Concrete

The compressive strength of various limerock concrete mixes
has been studied for several years at the University of Florida in
an effort to encourage the use of limerock as a concrete aggregate.
The results of this work have been published in Bulletin 7, “Lime-
rock Concrete, Part This bulletin covers the method of mixing
and placing limerock concrete, effect of mixing water on compres-
sive strength, and the most favorable conditions for limerock
concrete. It shows the need for careful water control in mixing
limerock concrete, and includes compressive strength data for the
various mixes from 1 :5 to 1 :9 by volume. The 1 :7 mix by volume
has generally been found to be the most economical mix. This mix
(1:7) with 0-1" slump will give a 28-day compressive strength of
about 1500-2000 psi. Figure 4 shows the mixing water/cement
ratio vs. compressive strength curve for various mixes, based on the
data taken from Bulletin 7.

The most recent test work on limerock concrete was done by the
State Road Department and the Portland Cement Association Re-
search Laboratory, Chicago, in studies for the experimental lime-
rock sections on US 441 just north of Gainesville, Florida. Both
the S. R. D. test data and the P. C. A. results are summarized in
the Florida State Road Department’s “Preliminary Report of Ex-
perimental Limerock Pavement Test Sections.” The data in Table
I are taken from this report. The screen analysis of the limerock
aggregate is very important. For best results the aggregate should
all pass the 1" screen. The following screen analysis is approxi-
mately the same as that of the aggregate used in the experimental
pavement test sections on US 441.

The laboratory tests made by the State Road Department are
in satisfactory agreement with the values in Table I found by the
P. C. A. Research Laboratory; both results substantiate the data
in Bulletin 7 and are further proof that limerock is a satisfactory
aggregate for 1500-2000 psi strength concrete.

*Univ. Florida Eng. & Ind. Exp. Sta., Bull. 7.

COMPRESSIVE STRENGTH - PSi at 28 days

PROPERTIES OF LIMEROCK CONCRETE

313

2 4 6 8 10 12 14

FREE MIXING WATER RATI 0-gallons PER SACK

Pig. 4 — Compressive strength at 28 days vs. free mixing water-cement
ratio for iimerock concrete.

TABLE I

Strength and Modulus of Elasticity of Limerogk
Concrete Specimens from the Florida State Road Department

by

The Portland Cement Association

Unvibrated specimens were cast on June 28, 1944, by the State Road
Department test laboratory in Gainesville. They were cured one day
under wet burlap, one day in a moist room and then packed in wet sawdust
for shipment to Chicago. They were received at the Chicago Research
Laboratory on July 20, placed in a moist room July 21 until tested at
28-day age on July 26, 1944. Slump of concrete was 2 in. Beams were
loaded on their sides as cast, at 1/3 point of 27 in. span.

314

JOURNAL OF FLORIDA ACADEMY OF SCIENCES

Mix Proportion

Strength at

28 days

Modulus of Elasticity

(Beams)
psi X 10-«

>5

•ession

" cylin-

iverage

linders

Flexure

6x6x30"

Beams

o

B ^ S

tangent

(b)

'm

a

1

Q

-I'

94:582

1:6.2

1.013

7.6 gal.

1360

280

1.98

2.00

1.34

94:456

1:4.9

0.893

6.7 gal.

1675

350

2.22

2.26

1.44

94 :374

1:4.0

0.720

5.4 gal.

2115

360

2.40

2.43

1.54

94:308

1:3.5

0.653

4.9 gal.

2405

420

2.60

2.66

1.66

94 :257

1:2.7

0.613

4.6 gal.

2745

480

2.86

2.86

1.89

(a) Tests made on July 21 before placing specimens in moist room.

(b) Tests made on July 26 after 5 days in moist room.

(c) Values calculated from load-deflection curves for beams.

The mechanical analysis of the aggregate used in the above laboratory
samples was as follows :

Total passing

1-1/2"

sieve

100%>

??

1"

99

96

3/4"

99

93

J?

1/2"

99

89

J?

3/8"

99

84

??

4

mesh

73

M >9

8

64

99 99

16

99

52

9 9 9 9

30

99

43

99 9 9

50

31

9 9 99

100

99

17

Fineness modulus

3.43

Dry rodded weight

per cu.

ft. 94 lbs.

Absorption

14.0%

THERMAL PROPERTIES

Thermal Conductivity of Limerock Concrete Walls
Since limerock concrete is finding' extensive use in the building
trades in the form of both monolithic and block structures, it was
thought that the heat conductivity properties of the concrete
should be determined. The thermal conductivity values of limerock
concrete at different moisture contents have been measured and
will be reported in a paper to be published elsewhere.

PROPERTIES OF LIMEROCK CONCRETE

315

The coefficient of thermal conductivity, k, of limerock concrete
is a function of temperature, composition, and moisture content.
The effect of composition is to increase the value of k with richer
mixes, e.g., the 1 :5 mix by volume has a k that is 10% larger than
the k for 1 :7 mix by volume. The effect of moisture is also to in-
crease the value of k, e.g., an increase of moisture from zero to 5%
increases the k of 1:5 mix by 23%. Therefore, limerock concrete
should be kept dry if the maximum heat insulation effect is de-
sired. The k for bone-dry limerock concrete is 0.51 for the 1 :7 mix
and 0.56 for the 1 :5 mix. The k for ordinary sand and gravel
concrete is l.OP (1:2.0: 2.75 mix).

The coefficient of thermal conductivity measures directly the
rate at which heat will flow through a homogeneous material, but it
does not give a complete picture of the heat insulation value of
walls or other heterogeneous constructions. For heterogeneous con-
structions the overall coefficient of heat conduction, U, must be
used for such comparisons. For a wall built up of a homogeneous
material (such as a poured concrete wall) of conductivity k and x
feet thick the coefficient of heat transmission, U, is determined by
equation (1) below:

11x1 (1)

U hi k ho

where U = the overall coefficient of heat transmission in Btu/(hr)
(sq ft) (deg F difference between the air on the two sides), and
h = the surface coefficient of heat transfer. Subscript i is used to
designate inside coefficient, and o, the outside coefficient.

For a wall with air space construction consisting of two homo-
geneous materials of thicknesses xi and X2, and conductivities ki
and k2, separated to form an air space of conductance a, the co-
efficient of transmission is

1 1 Xi 1 X2 1 (2)

U hi ki a k2 ho

The over-all coefficient of heat transmission, U, is the amount
of heat expressed in Btu transmitted in one hour per square foot
of the wall for a difference in temperature of 1 deg F between
the air on the outside and that on the inside of the wall. There-

to wley, F. B. and Algren, A. B. “Thermal Conductivity of Building
Materials,” Univ. Minn. Eng. Exp. Sta. Bull. 12. (1937).

316

JOURNAL OF FLORIDA ACADEMY OF SCIENCES

fore the value of U directly determines the insulation value of
a given wall. Low values of U mean good insulation construc-
tion and high values of U mean poor insulation construction.

Surface Coefficients of Heat Transfer: Heat is transmitted
to or from the surface of a wall by a combination of radiation,
conduction and convection. Because of these variables the sur-
face coefficients may be subject to wide fluctuations for different
materials and different conditions.

Values of hi in still and in moving air at different mean tem-
peratures have been determined for various building materials.^
The surface conductances, ho, for different materials at a mean
temperature of 20 deg F for different air velocities are given in the
A.S.H.y.E. Guide (22nd Edition, 1944, page 90). These values are
available for specific problems; however, the general comparison
of the heat insulating value of walls is made using an average value
for the surface coefficients hi and ho. The usual procedure is to
take hi =1.65 as an average inside coefficient and ho =6.0 as an
average outside coefficient for a 15 mph wind velocity.^ All of the
coefficients of transmission, U, in this report are calculated on this
assumption.

Calculation of TJ for Poured Concrete Walls: The equation 1,
above, is used for calculating the coefficient of transmission, U, of
poured concrete walls. The following data are used in the calcula-
tions of U of various concrete walls.
hi=1.65

ho=6.0

x=0.656 (7-7/8" wall — equivalent of the 8"x8"xl6"
block wall)

k=1.01^ for sand and gravel 1:2.0:2.75 mix
=0.88^ for limestone concrete 1:4.75 mix
=0.56 for limerock concrete 1 :5.0 mix
=0.51 for limerock concrete 1 :7.0 mix
=0.23® for clinker concrete

All the k ’s w^ere determined by the hot plate guard ring method on
dry concrete samples. The values of k=0.56 and 0.51 for limerock

^A.S.H.V.E. Research Report No. 869. “Surface Conductances as Affected
by Air Velocity. Temperature and Character of Surface,” by F. B. Rowley,
A. B. Algren and J. L. Blackshaw. Trans. Amer. Soc. Heat. Vent. Eng., 36 :
429. (1930).

^A.S.H.V.E. Guide, 22nd Edition, page 91. (1944). Amer. Soc. Heat. Vent.
Eng., 51 Madison Ave., New York, N. Y.

°Rowley and Algren, op. cit.

^Griffiths, Ezer. “Measurement of the Thermal Conductivity of Materials
Used in Building Construction.” Jour. Inst. Heat. Vent. Eng., 10: 106-138.
(1942-43).

PROPERTIES OF LIMEROCK CONCRETE

317

concrete in the above list are based on one thickness of test sample
as are the other values of k from the literature.

Then the coefficient of heat transmission for various 7-7/8"
poured concrete walls is as follows :

Wall No. 1.

Wall No. 2.

WaU No. S.

Wall No. 4.

Wall No. 5.

For a sand and gravel concrete wall:

1 1 0.656 1

— = + + = 1.42

U 1.65 1.01 6.0

U = 0.704 Btu /(hr) (sq ft) (deg F)

For a hard limestone concrete wall:

1 1 0.656 1

— == + + = 1.52

U 1.65 0.88 6.0

U = 0.658 Btu /(hr)(sq ft) (deg F)

For a Florida limerock concrete (1:5 mix)
poured wall:

1 1 0.656 1

— = + + = 1.94

U 1.65 0.56 6.0

U = 0.515 Btu /(hr)(sq ft) (deg F)

For a Florida limerock concrete (1:7 mix)
poured wall:

1 1 0.656 1

— = + + = 2.06

U 1.65 0.51 6.0

U = 0.485 Btu /(hr) (sq ft) (deg F)

For a clinker concrete poured wall:

1 1 0.656 1

— = + + = 3.62

U 1.65 0.23 6.0

U == 0.276 Btu /(hr) (sq ft) (deg F)

For a 14 inch sand and gravel concrete poured
wall:

1 1 14 1

— = + + = 1.93

U 1.65 12(1.01) 6.0

U = 0.517 Btu /(hr) (sq ft) (deg F)

Thus it is seen that a sand and gravel concrete wall has to
be almost twice as thick as a 7-78" limerock concrete wall
to have the equivalent heat insulation value.

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JOURNAL OF FLORIDA ACADEMY OF SCIENCES

Calculation of U for Concrete Bloch Walls: A standard con-
crete masonry unit is sketched in the accompanying diagram (Fig.
5). The dimensions of commercial blocks may vary somewhat from

Fig. 5 — Standard concrete masonry unit (8x8x16 inches).

plant to plant, but small variations in the dimensions will not af-
fect the calculated results appreciably. For purposes of calculation
this standard block can be split up into alternate solid slabs and
air containing sections as shown in Fig 5. Slab No. 1 is solid con-
crete of size 7-7/8"x7-7/8'xl-3/8". Slab No. 2 is a heterogeneous
section, size 7-7/8"x7-7/8"x2-19/32", made up of an inside concrete
prism, an air space and an outside concrete prism. The dimensions
are shown on the sketch in Fig 5. The complete wall can be vis-

PROPERTIES OF LIMEROCK CONCRETE

319

ualized as being made up of these two kinds of sections, and there-
fore, neglecting the mortar joints, the coefficient of transmission can
be calculated from a combination of the results of equations 1 and
2. The conductance, a, of the vertical air space in section No. 2 is
given as 1.10 in A.8.R.y.E. Guide (22nd Edition, page 98, 1944).

Wall No. 6. For a sand and gravel concrete masonry unit
wall:

Applying equation 1 to the slab No. 1 gives the
following value for coefficient of transmis-
sion, Ui, for that section:

1 1 0.656 1

— = + + = 1.41

ui 1.65 1.01 6.0

ui = 0.71

Equation 2 when applied to slab No. 2 gives
1 1 1.593 1 1.593 1

— = H + + — 1 = 1.95

U2 1.65 12(1.01) 1.10 12(1.01) 6.0

U2 = 0.51

Since slab No. 1 comprises 34.6% (1.375/3.97=34.6%) of the
face area and Slab No. 2, 65.4% of the face area perpendicular
to heat flow, the coefficient of transmission for the complete block
or wall is found to be :

U=0.346 Ui+0.654 U2
=0.346(0.71)4-0.654(0.51)

=0.58 Btu /(hr) (sq ft) (deg F)

This value of U agrees with the data in the A.8.R.Y.E. Guide,
(22nd Edition), very closely. The Guide gives U=0.56 for
this wall.

Wall No. 7. For a limerock concrete masonry unit wall.

Using the thermal conductivity value of 0.51
for 1 :7 mix limerock concrete gives the fol-
lowing values for coefficient of transmission
of the WaU:

For slab Jl 1 1 0.656 1

— = H = 2.06

ui 1.65 0.51 6.0

ui = 0.485

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JOURNAL OF FLORIDA ACADEMY OF SCIENCES

For slab #2 1 1 1.593 1 1.593 1

+ -j -| 1 =: 2.20

U2 1.65 12(0.51) 1.10 12(0.51) 6.0

U2 = 0.454

Therefore U = 0.346 (0.485) +0.654 (0.454)

-U= 0.46 Btu /(hr)(sq ft) (deg F)

It is seen that under the same conditions a sand and gravel
concrete block wall will conduct 26% more heat through the wall
than will a limerock concrete block wall.

Comparison of U for Frame Walls and Concrete Block Walls:
The A.S.H.Y.E. Guide, (22nd Edition, page 100) gives a table of
values for coefficients of transmission, U, for common frame walls
such as that sketched in Fig. 6. These values are tabulated in
Table II together with the coefficients for various concrete walls.
All the tabulated values in Table II were determined for the same
conditions; i. e., hi =1.65 and ho =6.0.

It appears that concrete masonry unit walls cannot approach
wood frame structures in insulation value unless they are made of
special aggregate concrete blocks or have additional insulation
material in the interior. However when interior insulation material
is used with limerock concrete blocks or sand and gravel concrete
blocks, a wall whose coefficient of transmission is equal to that of
a frame wall is obtained.

PROPERTIES OF LIMEROCK CONCRETE

321

When sand and gravel concrete block walls have an interior
finish consisting of metal lath and 3/4" plaster on 2" furring strips,
the coefficient of transmission is much reduced. The calculations
below (based on the slab method used in the previous section) show
how effective this type of interior finish is in reducing the co-
efficient of transmission. The conductance of each air space (block
hole and furred area) is taken as 1.10 and that of 3/4" plaster on
metal lath as 4.40 in accordance with the A.8.H.V.E. Guide, (22nd
Edition, 1944).

Wall No. 8

For slab #1 1 1 0.656 1 1 1

— = + + + 1 = 2.56

ui 6.0 1.01 1.10 4.40 1.65

Ui = 0.39

For slab #2 1 1 1.593 1 1.593 1

— — -j- ' + + i

U2 6.0 12(1.01) 1.10 12(1.01) 1.10

1 1

+ + = 3.09

4.40 1.65

U2 = 0.32

Then the coefficient of transmission of the complete wall is,

U==0.346 (0.39) + 0.654 (0.32)

=0.34 Btu /(hr) (sq ft) (deg P)

Using the same wall construction as Wall No. 8 above and
limerock concrete blocks (1:7 mix whose k=0.51) instead of
sand and gravel concrete blocks, the coefficient of transmission
is as follows:

Wall No. 9

For slab #1 1 1 0.656 1 1 1

— — -|- -|- _|- — ^ ■ ■ -] = 3.20

ui 6.0 0.51 1.10 4.40 1.65

ui = 0.312

For slab #2 1 1 1.593 1 1.593 1

— — _j- {

U2 6.0 12(0.51) 1.10 12(0.51) 1.10

1 1

+ + = 3.34

4.40 1.65

U2 = 0.30

Then,

U=0.346(0.31) + 0.654(0.30)

=0.30 Btu /(hr) (sq ft) (deg F)

322

JOURNAL OF FLORIDA ACADEMY OF SCIENCES

Therefore concrete block walls can be made equal to frame walls
(see Table II) in heat insulating effect by finishing the interior of
the wall with metal lath and 3/4" plaster on 2" furring strips.
Plastering directly onto the concrete blocks would not increase the
heat insulating effect of the wall appreciably as it is the air space
furnished by the furring strip which gives the increased insulation
effect. The air space would also block water transmission through
a concrete block wall.

Concrete block walls with an interior finish of gypsum board
(3/8") on 2" furring strips would have the same coefficient of
transmission as the walls finished with plaster on 2" furring strips.

When the interior finish of a sand and gravel concrete block
wall is made up of insulation board (k=0.028) on 2" furring
strips the coefficient of transmission, U, is equal to that of the
better frame constructions. The following calculations show this in
detail :

Wall No. 10.

For slab #1 1 1 0.656 1 0.5 1

— = + + + + — = 3.82

ui 6.0 1.01 1.10 12(0.028) 1.65

Ui = 0.262

J^'or slab #2 1 1 1.593 1 1.593 1

— — _|_ -}- 1

U2 6.0 12(1.01) 1.10 12(1.01) 1.10

0.5 1

+ + = 4.35

12(0.028) 1.65

U2 = 0.23

Then the coefficient of transmission of the complete wall is,

U=0.346 (0.262) + 0.654 (0.23)

=0.24 Btu /(hr)(sq ft) (deg F)

Using the same construction as Wall No. 10 above and sub-
stituting limerock concrete blocks for the sand and gravel blocks
gives a wall with the following coefficient of transmission:

Wall No. 11.

For slab #1 1 1 0.656 1 0.5

— — _j_ _|-

ui 6.0 0.51 1.10 12(0.028)

1

+ = 4.46

1.65

ui = 0.224

PROPERTIES OF LIMEROCK CONCRETE

323

For slab #2 1 1 1.593 1

— = H +

U2 6.0 12(0.51) 1.10

1 0.5 1

+ h + =

1.10 12(0.028) 1.65

U2— 0.217

U =0.346 (0.224) + 0.654 (0.217)
==0.22 Btu /(hr)(sq ft) (deg F)

1.593

+

12(0.51)

4.60

These insulated concrete block wall constructions have a
coefficient of transmission equal to the better frame wall con-
structions. The calculated coefficients of transmission for vari-
ous concrete constructions are tabulated in Table II together
with the accepted coefficients for frame wall constructions.

TABLE II

Coefficients of Transmission, U, for Various Walls
Frame Construction (A.S.H.V.E. Guide, 22nd Edition, p. 100)

Exterior Finish Type of Sheathing Interior Finish U

Type I Construction (Fig. 6)

a. Wood Siding Gypsum (%")

b. Wood Siding Wood (25/32") & building paper

c. Wood Siding Wood (25/32") & building paper
Type II Construction (Fig. 6)

a. Stucco Gypsum (%")

b. Stucco Wood (25/32") & building paper

c. Stucco Wood (25/32") & building paper

Type III Construction (Fig. 6)

a. Brick Veneer Gypsum (i/^")

b. Brick Veneer Wood (25/32") & building paper

c. Brick Veneer Wood (25/32") & building paper

Metal lath & plaster 0.33
Metal lath & plaster 0.26
Wood lath & plaster 0.25

Metal lath & plaster 0.43
Metal lath & plaster 0.32
Wood lath & plaster 0.30

Metal lath & plaster 0.37
Metal lath & plaster 0.28
Wood lath & plaster 0.27

Concrete Construction (Results from this paper)

Wall No. Interior Finish XT

Concrete poured walls (7-7/8"), smooth surface.

1

Sand & gravel

1 :2.0 :2.75

0.70

2

Limestone

1 :4.75

0.66

3

Limerock

1:5

0.52

4

Limerock

1:7

0.49

5

Clinker concrete

0.28

Concrete block walls

(7-7/8")

6

Sand & gravel

1 :2.0 :2.75

0.58

7

Limerock

1:7

0.46

8

Sand & gravel

1 :2.0 :2.75

Metal lath & 3/4'

" plaster, furred

0.34

9

Limerock

1:7

Metal lath & 3/4'

" plaster, furred

0.30

10

Sand & gravel

1 :2.0 :2.75

Insulation board

(Va"), furred

0.24

11

Limerock

1:7

Insulation board

(%"), furred

0.22

324

JOURNAL OF FLORIDA ACADEMY OF SCIENCES

Thermal Expansion of Limerock Concrete

The rate of expansion of concrete with temperature is a prop-
erty of scientific and technologic importance. It determines the
spacing of expansion joints in structures and the type of rein-
forcing material usable in concrete. It may be expressed in several
ways, of which the commonest is the mean coefficient of expan-
sion, a. It is the increase of length M==42 — h, of the specimen,
divided by the original length li, when heated over the tempera-
ture interval AT==T2 — Ti; that is, the change in length per unit
of length per degree Fahrenheit rise in temperature.

1 M

a =

h AT

The method used for determining the coefficient of expansion
of concrete was to measure directly, with an extensometer, the
expansion in length which a beam undergoes when heated over a
definite temperature interval. The extensometer was lagged with
1%" 85% magnesia insulation to eliminate temperature changes
and was equipped with a dial guage which gave the expansion
changes in 0.001". A stainless steel rod of known composition was
used for checking the equipment and the method used in the
laboratory. Since age and moisture content cause dimensional
changes in concrete every effort was made to take each set of
measurements at a constant moisture content and the same age.

The concrete specimens were made from 1:7 & 1 :5 mixes by
volume and were cast in the form of 3" x 3i/^" x 24" beams with
stainless steel reference tips placed in the ends of each beam for
accurate measurement of the length changes on heating. A ther-
mocouple was cast in the center of each beam for use as a tempera-
ture measuring device. The center temperature was taken as the
temperature of the whole beam.

When length measurements were made the reference point of
one end of the concrete beam was placed on the base point of the
extensometer and the top reference point of the beam was placed
under the dial guage feeler. Since the tips of the reference points
were rounded, the maximum dial guage reading was used each
time. At the same time that length measurements were made,
corresponding temperatures were measured for the concrete beam
and extensometer beam so that accurate calculations could be made.
Fig. 7 shows a concrete beam in the extensometer ready for a length
measurement.

The stainless steel (18-8) rod used for checking the accuracy of
the equipment and the method was diameter and 24.7" long

Fig. 7 — Concrete beam placed in the extensometer for making a

length measurement

Fig. 8 — Laboratory apparatus for measuring water transmission of

concrete samples.

PROPERTIES OF LIMEROCK CONCRETE

325

with the ends machined to have the same shape as the reference
points set in the concrete. Two thermo-couples were soldered to
the rod, one on the center and the other about 1'' from one end.
Length measurements were made when both thermocouples indi-
cated the same temperature. The completed rod was encased with
1^" thickness of 85% magnesia insulation. Handbook data give
the coefficient of expansion of stainless steel (18-8) as 9.8x10’®
foot per foot per degree Fahrenheit in the 70-212 F temperature
range.

In the laboratory the average of 6 measurements on this rod
gave 9.5xlO’®/F as the coefficient of expansion with a maximum
deviation of any one measurement of ziz0.2xl0-®/F. Since the
maximum deviation of any one measurement was rather small and
the difference in values of the handbook data and these data could
be explained on a basis of difference in heat treatment of the steel,
it is believed that this method and equipment gives good results.

The data on concrete beams were taken in order to determine
any effect moisture content would have on expansivity. From 28
observations made at different moisture contents on both 1 :5 and
1:7 mixes it appears that any effect moisture content has upon
expansivity must be negligible for no appreciable trend was found
in a for moisture contents from dry to saturated. The following
data on beam A2 (1 :7 mix) is representative of the constancy of a
with changes in moisture content :

Effect of Moisture on Expansivity
Moisture (% by weight) a

12.0 (saturated) 3.3x10’®

10.7 3.6

9.1 3.4

7.8 3.6

5.0 3.3

1.8 3.2

0.5 3.2

Average 3.4xlO’®/F

The results of 14 measurements on each pair of beams made
from 1 :5 and 1 :7 mixes give expansivities as follows :

Effect of Composition on Expansivity
Mix a Max. Deviation

1:5 by volume 3.4xlO-®/F ztO.3

1:7 by volume 3.4xlO-®/F ±0.2

S. L. Meyers^ gives the following values for expansivity of lime-
ys. L. Meyers, “Thermal Coefficient of Expansion of Portland Cement —
Long Time Tests.” Indust. & Eng. Chem., 32; 1107-12, (1940).

326

JOURNAL OF FLORIDA ACADEMY OF SCIENCES

stone concrete (1:3.1 mix) for different ages and storage
conditions :

Effect of Age and Storage Conditions on Expansivity of
Limestone Concrete

Hard Limestone Concrete

1 :3.1 mix

0

1/2

1

2

4 yrs.

a. Dry Storage

5.0

7.9

5.3

3.9

3.4xl0-®/P

b. Enclosed air storage

2.9

3.2

3.3

3.4

3.0

c. Water storage

2.5

2.6

2.8

2.7

2.3

Thus our results are about the same magnitude as the values for
hard limestone concrete under enclosed air storage conditions.
Note the fact that water storage produces a material which is least
affected by temperature expansions and that the expansivity does
not change appreciably with age.

Meyers gives the expansivity of various concrete mixes as
follows :

Effect of Richness of Mix and Different Aggregate on
Thermal Coefficient of Expansion
(Data on 2 year-old samples)

Mix axlO"® per P

Neat normal cement .....10.3

1 cement : 1 sand 7.5

1 cement : 3 sand 6.2

1 cement : 6 sand 5.6

Flint aggregate 1:4.7 mix 7.2

Sand aggregate 1 :4.7 mix 4.8

Granite aggregate 1 :4.7 mix 4.8

One point of universal agreement is that the coefficient of ex-
pansion increases with richness of mix as illustrated by the above
data.

Engineers usually use an approximate coefficient of thermal
expansion for ordinary concrete of 5.5x10'® per P, and the expan-
sivity of concrete reinforcing steel is generally taken as 6.0x10'®
per P. Then limerock concrete expands much less than ordinary
concrete. As an example, the expansion of a 100 foot limerock
concrete slab for an 80° F temperature rise amounts to only
3.4xl0'®xl00xl2x80=0.33 inches.

whereas, an ordinary concrete slab under similar conditions would
expand much more,

5.5xl0'®xl00xl2x80— 0.53 inches.

As a result expansion joints in limerock concrete need be smaller
or less frequent than in ordinary concrete structures.

The effect of using reinforcing steel whose a =6.0x10'® per P

PROPERTIES OF LIMEROCK CONCRETE

327

with limerock concrete whose a =3.4x10"® per F is not known but
the stainless steel reference points used in the test beams and whose
a =9.8x10"® were still bonded tight after some of the beams have
been heated and cooled over a 125 P temperature change as much
as seven times.

WATER PROPERTIES OF LIMEROCK CONCRETE
Expansion of Limerock Concrete With Increase of Moisture.

Most materials change dimension with a gain or loss of water.
Concretes are no exception — ^they increase in length on taking up
water to the saturation point and decrease in length upon drying.
Data in the literature on this phenomenum are very sparse; how-
ever, Miller and Snyder® found that the average expansion due to
wetting clay tile (28-days in water) was 0.5x10"^ ft per ft of
length, or 0.6" per 1000' tile and for dry tamped concrete tile the
average expansion due to wetting was 4.6x10"'^ ft per ft of length
or 5.5" per 1000 ft of concrete tile. Wendt and Woodworth® found
that the expansion due to wetting a 1:3.45:2.3 (3.7 gal/sk mixing
water) sand and gravel masonry unit was 3.7" per 1000 ft.

This change of length with moisture content is probably of
greater magnitude than is generally recognized by the construction
men in the industry. Using Wendt and Woodworth ^s figure, a
16" dry tamped concrete block if put up wet would contract 0.0059"
on drying out. This appears to be a negligible contraction, but it
is probably enough to set up stresses in the block that would frac-
ture occasional blocks in the wall.

The expansion of limerock concrete (plastic mix) due to wet-
ting was measured by using the same technique and equipment
described in the previous section. Two pairs of beams, 8 months of
age, were used for measurement. The length of the bone-dry beams
was measured and compared with the 28-day water soaked length
of beam. The average expansion due to wetting was 3.3x10"^ ft per
ft of length. There was no apparent difference in expansion be-
tween the 1 :5 and the 1 :7 mix by volume, although the 1 :7 mix
absorbs 13.0% moisture compared to 12.4% moisture absorbed by
the 1 :5 mix. This expansion of limerock concrete due to wetting is
equivalent to the expansion resulting from a 95 deg F rise in tem-
perature. Common practice is to design thermal expansion joints
for an 80 deg F rise and neglect expansion due to wetting entirely.

*:Miller, D. G. and Snyder, C. G. “Expansion of Clay and Concrete Drain
Tile due to Increase of Temi)erature and Moisture Content.” Agri. Eng.,
25: 179. (1944).

“Wendt, K. F. and Woodworth, P. M. “Tests on Concrete Masonry Units
Using Tamping and Vibration Molding Methods.” Jour. Amer. Concrete
Inst., 36: 27. (1939).

328

JOURNAL OF FLORIDA ACADEMY OF SCIENCES

As a result of this experimental work, it appears that allowances
should be made for expansion due to wetting in addition to the
usual allowances for thermal expansion, especially if the structure
is exposed to wetting and drying conditions.

Results op Water Transmission Measurements

Water leaks in concrete masonry walls occur from two sources,
(a) porous areas and leaks in the units themselves, and (b) leaks
in the mortar joints between the units. If the masonry units were
completely sealed there would still be trouble with leaks through
the mortar joints. The remedy for eliminating leaks from walls is
to seal the outside surface of the finished wall. Sealing the units
at the plant is only half the answer. Properly tooling the mortar
joint will eliminate many leaks and put more emphasis on pro-
ducing good, tight masonry units.

Test Work: The experimental work on this problem was con-
ducted on slabs cut from commercial limerock masonry units. Com-
mercial samples were used since they are analogous to an actual
wall and will be more uniformly packed than a hand made product.

On testing li^"x7-3/4"x7-3/4" slabs cut from commercial ma-
sonry units it was found that of 21 samples tested only 4, or 19%,
were ‘ ‘ water tight ’ ’ ; that is, water did not leak through and drop
from the underside of the block.

The test apparatus is shown in the accompanying photograph
(Fig. 8). The test was designed to measure the rate of loss of
water through the concrete slab when water is held on one surface
of the concrete and free evaporation is allowed on the other surface.
A calibrated container of distilled water was clamped onto the top
side of the concrete slab and free air was allowed to circulate on
the bottom side of the slab. The measurements were made on the
basis of the amount of water passing through and evaporating
from the underside of the slab per day. Two coats of aluminum
Xngment paint were used on the edges and face of each slab to
limit the test area to 6"x6". All slabs were in thickness., The
absolute rate measurements are grams of water per day passing
through a 36 sq. in. area of concrete thick. Unless the slab
was classed as leaky, a film of water never collected on the un-
derside of the slab.

Various surface treatments have been applied to the leaky slabs
in an effort to determine each treatment’s effectiveness in sealing
leaky concrete slabs and also in decreasing the water transmission
rate of non-leaking concrete slabs. Each treatment was tested on
two leaky concrete slabs to obtain an average result. Only 19% of
the untreated slabs did not leak on test.

PROPERTIES OF LIMEROCK CONCRETE

329

TABLE III

Summary of Treatment Processes with Test Results on
Limerock Concrete Slabs

1 unit of water /(day) (36 sq in)= 0.28 lbs water /(day) (sq ft)
Water Transmission

Material and Treatment Rate Remarks

units/ (day) (36 sq in)

Before treatment

Red Clay Brick 1.5 to

Untreated non-leaky Concrete Slabs 1.0 to
After treatment

1. Asphalt Material

a. Emulsion applied in 2 coats

with a stiff brush. 0.4

b. Cutback RCIS applied in 3

coats with stiff brush. Leak

2. Na Silicate “o” Brand applied

in 3 coats of dilute solution fol-
lowed by an acid wash. 1.5

3. Linseed Replacement Oil (Dutch
Boy) applied by stiff brush in 4
coats. 0.5

4. Zn Stearate applied in 10% kero-

sene solution by stiff brush in 2
coats. 2.4

5. Ethyl silicate. Three coats of a

partially hydrolised solution were
brushed on the surface. 2.3

6. Vinyl copolymer paint applied by
stiff brush in two coats. 0.2

2.0

2.0 Only 19% did not leak
Very low rate after treat-
ment. Emulsion penetrated
pores very well. Poor color.
Three coats of asphalt did not
seal leaks. Emulsion was
more satisfactory to apply.
Poor color.

Two such treatments were
required to seal leaks and
then the water rate was not
decreased. It produced a clean
inert whitish surface.

Large number of coats re-
quired to seal leaks. Oil pene-
trated very well and was very
effective in reducing water
rate of concrete.

One slab leaked after two
coats. Surface was very water
repellent.

This solution left the concrete
surface in its natural color
and some harder. Apparently
it did not seal leaks very well
for one slab leaked after 3
coats.

Produced a lustrous film over
the natural color concrete.
Sealed leaks and had very
low water transmission.

7. Synthetic resin paint Type B.
Two coats were applied by stiff
brush.

8. Ceramic seal coat cement. Two
coats were brushed on with stiff
brush and allowed to set.

9. Limerock Cement Paint. Two
coats of a 1 ;2 weight cement :
limerock (-100 mesh) mix were
brushed on with stiff brush.

10. Limerock Cement water Repel-
lent Paint. Same as No. 9 except
1% A1 stearate based on cement
and limerock was added.

Gave very good results simi-
lar to Vinyl copolymer.

0.3

Gave attractive finish and
was good sealing material.

1.5

Sealed leaks very well and
had fairly low water trans-
mission.

0.9

Sealed blocks effectively and
gave water repellency to sur-
face. This would probably be
1.0 a great advantage on vertical
walls.

330

JOURNAL OF FLORIDA ACADEMY OF SCIENCES

The emtilsified asphalt was very effective in sealing the leaks
and pores in the concrete. When the emulsion is put on with a stiff
brush it appears to penetrate the pores and holes in the surface
very well. The black color is objectionable.

The vinyl copolymer and sjmthetic resin base paints gave good
results on sealing the leaks in the slabs and both had very low
water transmission rates. They are probably too expensive ($5-$6
per gallon) to be considered for general use.

The ceramic seal coat cement gave good results as a sealing
compound but the water transmission rate is higher than that of
cement-water paints.

At present the most satisfactory solution to the waterproofing
problem from both cost and performance viewpoints, is the use of
Portland cement-water paints. Tests show that the cement-water
paints were very effective in sealing the leaks in the surface and
they also lower the water transmission. They are the cheapest and
most durable treatment tested. Adding 1% of aluminum stearate
to the cement paint before mixing gives water repellent properties
to the paint film. By actual tests made on an ordinary cement
paint film and a water repellent cement paint film (1% alumi-
num stearate) it was found that water dropped on the ordinary
cement paint penetrates into the film in 10 to 15 seconds as com-
pared to no penetration of the water drops into the repellent
film on standing 3 to 4 hours. In fact, the water drops on the
repellent surface evaporate before they penetrate the film. The
repellent films have the same water transmission as ordinary
cement paint films.

The National Bureau of Standards in Tests of Cement-Water
Paints and Other Waterproof ings for Unit-Masonry Walls
found that cement-water paints were more effective as waterproof-
ings than oil-base and emulsified resin paints. They also found
that bituminous coatings applied to the inside faces of brick walls
were ineffective as water-proofings and that brush coatings of
Portland cement and sand were more effective.

The American Concrete Institute Committee 616 report on
“The Nature of Portland Cement Paints and Proposed Recom-
mended Practice for Their Application to Concrete Surfaces
covers the composition, mixing, and application of cement-water
paints to concrete surfaces.

It appears that there is no reason for a leaky concrete wall to
exist when cement-water paints are available.

^•Obtainable from Superintendent of Documents, Washington, D. C. as
Building Materials & Structures Report BMS 95, Price 15c.

^Jour. Amer. Concrete Inst., 13: 485-501. (1942).