The 47^{th} Problem of Euclid

By

H. Meij

Master, Harmony Lodge #18

August 2000

Portrait of Euclid according to an old European etching

**Introduction:**

There are so many symbols,
words and phrases in Freemasonry used both as part of its rituals as well as
part of its vocabulary, that studying and trying to understand the gmeaningsh
them is a very worthwhile and a rewarding
journey. One such prominent symbol and phrase, is the 47^{th} problem of
Euclid, which is one of the main symbols introduced in the Third Degree.

In the Blue Lodge, it is considered a great honor to be elected and serve as the Master of a lodge. It shows that the individual has attained maturity, leadership, charisma, and motivation, but above all, knowledge to be able to lead others. It is an initiation by itself, as the position brings with it a completely new set of responsibilities that are often not appreciated when accepting the position. At the end of serving as Master of a Lodge, many Past Masters are presented with a jewel, symbolizing the great appreciation of the Lodge towards their dedication. It also symbolizes something else ? that is that the individual has completed his gjourneyh, through the different positions of the Lodge, to a new plain.

The 47^{th} problem of Euclid features prominently in
many Past Masterfs jewels.
Selecting this symbol out of the thousands used in Freemasonry to represent one
of its highest honors must mean that it is a very significant and central symbol
of the Craft. Yet, sadly many Freemasons, even many Past Masters, do not know
why it is so centrally featured in the Past Masterfs jewel. Clearly the 47^{th}
problem is based on Geometry, and all Freemasons know that Geometry and
Freemasonry are closely linked, but is this the only reason? What does the
47^{th} problem of Euclid symbolize and mean? Of the 465 problems
published by Euclid, why is the 47^{th} so important? Why do Freemasons
cherish it so?

(An example of a Past Masterfs Jewel featuring the 47^{th} Problem of Euclid from
England. Past Masterfs
jewel used in the USA often do not show the 47^{th} Problem
anymore)

**The Foundation of Freemasonry?:**

The 47^{th} problem of Euclid is often mentioned in
Masonic publications. In Anderson's gConstitutionsh published in 1723, it mentions that gThe Greater Pythagoras, provided the Author of the 47th
Proposition of Euclid's first Book, which, if duly observed, is the Foundation
of all Masonry, sacred, civil, and militarych. Being mentioned in one of the first gofficialh
speculative Masonic publications clearly
indicates that the 47^{th} problem of Euclid must be important. It is
also mentioned in the Third Degree lecture, where we are taught that the
g47^{TH} problem of
Euclidcc.taught us to be
general lovers of the arts and sciencesh.

However, it is quite different to be referred to as the
gFoundation of all Masonry,
sacred, civil and militaryh that to be referred to as gtaught us to be general lovers of the arts and sciencesh. Has the importance of the symbolism
of the 47^{th} problem declined over time for some reason?

In order to understand whether the symbol has declined in
importance or not, we first need to look at the 47^{th} problem of
Euclid itself.

**The Discovery of the 47 ^{th} problem of
Euclid**

Euclid wrote a set of thirteen books, which were called
gElementsh. Each book contained many geometric
propositions and explanations, and in total Euclid published 465 problems. The
47^{th} problem was set out in Book 1, which is also known as
gThe Pythagorean
Theoremh. Why is it called
by both these names? Although Euclid published the proposition, it was
Pythagoras who discovered it. We learn from the third degree lecture that:

gThis wise philosopher (Pythagoras) enriched his mind abundantly in a general knowledge of things, and more especially in Geometry, or Masonry. On this subject he drew out many problems and theorems, and, among the most distinguished, he erected this, when, in the joy of his heart, he exclaimed Eureka, in the Greek language signifying, "I have found it," and upon the discovery of which he is said to have sacrificed a hecatomb. It teaches Masons to be general lovers of the arts and sciencesh.

Actually, it was not Pythagoras who directly discovered the
rule, as the Egyptians used the same principle for a very long time before
Pythagoras, whereby they re-measured their fields after the annual flooding of
the Nile washed out their boundary markers. Hence, Pythagoras is probably here
referred to as being the one who __proved__ that the process
works.

History records that
Pythagoras established a society with philosophical, religious and political
aims. Shrouded in secrecy, they believed that only by truly understanding the
universe could one achieve salvation of the soul, and as Divinity created all
things, studying it over a period of several lifetimes, could bring one closer
to Divinity itself. As such, it was believed that through study and reason could
one start to understand Divinity. Clearly, reason is based on measurable things
(such as through numbers and objects), and is easier to understand if expressed
in that matter. Hence the society devoted much of its time to the mathematics,
including Geometry. This line of thinking was incorporated in Freemasonry, which
sets it opposite to the Church, which emphasizes faith over reason. Indeed, Pope
Pius IX, in his encyclical, *Qui Pluribus*, dated 9 November 1846, attacked
those who gput human reason
above faith, and who believe in human progress.h
Many people consider this to be a reference to
Freemasonry.

This is interesting, because in the Book of Wisdom 11:20 we read:

gEven apart
from these, men could fall at a single breath

when pursued by justice

and
scattered by the breath of thy power.

But thou hast arranged all things by
measure

and number and weight.h

So the very gmeasurement of thingsh the Church objects to is mentioned in Scripture.

However, let us get back to how the 47^{th} problem
fits in Freemasonry.

**What Does the 47 ^{th} say?:**

The proposition states that: gIn right angled triangles the square on the side subtending the right angle is equal to the squares on the sides containing the right angle.h

What? In other words A2 + B2 = C2.

Many readers will feel like they have been returned to Geometry class. A simple illustration will probably refresh our memories.

The proposition is especially important in architecture. Builders have since ancient times used the theorem in constructing buildings by a process known as gsquaring a room.h As the theorem states that 3 squared + 4 squared = 5 squared, a builder starts by marking a spot and drawing a line, say line A. This line is given the value of 3. The builder then marks another point, say point B and draws a line from it at a right angle to line A, and it is given the value of 4. The distance between line A and B is then measured, and if the distance between A and B is 5, then the room is squared. By inverting the process, a gsquaredh (or rectangle) room can be obtained.

Engineers who tunnel from both sides through a mountain use the
47^{th} problem to get the two shafts to meet in the center. The
surveyor who wants to know how high a mountain may be ascertains the answer
through the 47th problem. The astronomer who calculates the distance of the sun,
the moon, the planets, and who fixes "the duration of times and seasons, years,
and cycles," depends upon the 47th problem for his results. The navigator
traveling the trackless seas uses the 47th problem in determining his latitude,
his longitude, and his true time. Eclipses are predicted, tides are specified as
to height and time of occurrence, land is surveyed, roads run, shafts dug,
bridges built, with the 47th problem to show the way.

In some lodges, using this principle, a candidate symbolically gsquares the Lodgeh by being escorted around the Lodge three times during the Entered Apprentice ritual, four times for a Fellowcraft ritual, and five times for a Master Mason ritual, which completed his journey.

(1738 German Drawing depicting workmen using the
47^{th} problem)

__The 47 ^{th} problem forms the basis of all
ancient measurement units:__

The 47^{th} problem of Euclid formed the basis of a
common set of measurements used by the Egyptians, especially in the building of
the Great Pyramids. It gets a little technical, but a simple illustration will
help us understand it better.

@

Please see the illustration above,
which is not accurate due to a drawing, but will serve to illustrate the point.
If we take a circle and draw in it a triangle (triangle A- B-C) which
perpendicular is 300, base is 400, and by the 47^{th} problem, the
hypotenuse becomes 500 (any combination such as 3,4,5 will also work ? higher
numbers are used for ease of explanation). Then if we draw a line from the angle
of the perpendicular and the base through the hypotenuse to the circle, this
line will be equal to 480. The

resulting two parts of the hypotenuse (A-D and D-C) will be equal to 180 and 320 respectively. Then if we draw another line from the point D (the intersector of the hypotenuse) to the perpendicular of the shortest side of the triangle (A-B), then line A-E will equal 108 and line D-E will equal 144.

Now we have all the measurements of the ancient world, that is 500, 480, 400, 320, 180, 144 and 108. Why is this important? If we take each unit to be a cubit (an ancient form of measurement), then 500 is the base of the Great Pyramid of Memphis. 400 cubits is the length of an Egyptian stadium (stadium is plural for stadia, and ancient measurement unit, based on a particular number of steps, also called a Khet by the Egyptians). 480 cubits is the length of the Ptolemy stadium, 320 cubits is the length of the Hebrew and Babylonian stadium. Furthermore, 180, which represents the smaller part of the hypotenuse, doubled gives 360 cubits, the Cleomedes stadium. By doubling 144 cubits gives 288 cubits, the Archimedes stadium. Finally by doubling 108 cubits we obtain 216 cubits, or the lesser Egyptian stadium.

In other words, this simple exercise formed the basis of all the lengths used by the Egyptians, and hence also once again indicates that its principle was well understood by the Egyptians, and hence taught by them to Pythagoras.

**Conclusion:**

Clearly, the 47^{th} problem helps us look at the
universe, and all that is in it, through a system that we can understand
clearly, for it is measurable. The Masterfs jewel is the square, the base needed for the
47^{th} problem (in many jurisdictions the square has the dimensions of
3:4 ? the Pythagorean dimensions). As the Master serves his position, he becomes
more complete, and therefore the 47^{th} problem of Euclid is dedicated
on his jewel when he leaves office.

**References:**** **

Circumambulation and Euclidfs 47^{th} proposition, by Reid McInvale

Encyclopedia of Freemasonry, by Albert Mackey

Freemasonry, A journey through ritual and symbol, by W. Kirk

Master Mason, by Carl Claudy