Number π and Solomon's molten sea
As stated in Ch.7 of the book of Kings I, King Solomon ordered Hiram from Zor to make, among other things, a molten sea. "And he made a molten sea, ten cubits from the one brim to the other: it was round all about, and its height was five cubits: and a line of thirty cubits did circle it round about" (Kings I, Ch. 7:23) (see the side view and the view from above). Since the diameter of the vessel was 10 cubits and the circumference 30, their ratio was 3. Quite a poor approximation of the number π=3.1415…! Perhaps the diameter of 10 cubits included the thickness of the walls of the vessel, while the perimeter was measured from inside? Indeed the Talmud in Iruvin 14a makes such a suggestion. However it is rejected immediately. The Talmud cites the verse which says "and it was a hand breadth thick, and brim was wrought like the brim of a cup, like the petals of a lily". The Talmud infers from this sentence that the thickness of the brim was negligible. Besides, the Talmud claims that both measures: the diameter and the perimeter are the inner ones. The Talmud comes from it to the conclusion that the ratio of circle to its diameter is 3! In the sequel the Talmud discusses the volume of the vessel. At the end of the verse is written: "it contained two thousand bat". The "bat" equals 3 seah while 40 seah make up a miqveh of 3 cubic cubits. Hence the volume of the sea was 450 cubic cubits. The Talmud however calculates the volume of the cylinder assuming that π=3 and arrives at 3∙52∙5=375 cub. cubits, i.e. 5/6 times less than required. Then Talmud quotes an external source ("braita") saying that the Solomon sea for the first 3 cubits of its height was square and for the next 2 cubits was round. Hence the volume of the sea was 102∙3+3∙52∙2=450, exactly as stated in the book of Kings!
Is it possible that the sages of Talmud thought that π is exactly 3? Even a rough measurement would show that π is larger than 3! The approximation of π by the ratio 22/7 was known in the ancient time. It is impossible to imagine that King Solomon, the wisest of all men, did not know this elementary fact. And at the same time he was able to manufacture a gigantic copper vessel of a given size and volume.
Somebody drew attention to the fact that the word "line" in the verse is written in a strange way (some attribute this remark to Hagra- the genius from Vilno, but in his books it is not found). Namely. it is written as ÷åä (Quf, Vav, Hey) instead of the correct ÷å, while on the margin of the page appears a correction: read ÷å (Quf,Vav). There are several instances in the Tanach when a word is spelled in one way and is pronounced a little differently. As a rule we don't know the reason for these differences. In our specific case the following explanation was suggested. As well known, the Hebrew letters have numerical values, Alef=1, Bet=2, Gimmel=3, Dalet=4, Hey=5, Vav=6, etc, Yud=10, Qaf=20 Lamed=30 etc., Quf=100, Reish=200 etc. A word has a numerical value (Gematria) equal the sum of its letters. Hence the word ÷åä (qava) has a numerical value of 100+6+5=111 while the word ÷å (qav) - 100+6=106. If one multiplies the "wrong" ratio 30/10 written explicitly by the correction ÷å/÷åä=111/106, one obtains the ratio 333/106=3.141509. This is an approximation of π=3.1415926… with 5 significant digits.
The number π as any number could be expanded into continuous fraction a+1/(b+1/(c+1/(d+…)). In the case of π a=3, b=7, c=15, d=1. The ratio 333/106=3+(1/(7+1/15)) is a second approximation of π. The fist approximation is 22/7, the third is 355/113=3.1415929… It is remarkable that the first three approximations of π are extremely efficient, i.e. they are very close to π while having small denominators.
It appears to me that the correction ÷å/÷åä (qava/qav) has not merely numerical meaning. The word ÷åä (qava) is feminine (in Hebrew the feminine words almost always end with ä) while ÷å (qav) is masculine. The way the word is spelled is called "masoret"-îñåøú and is feminine, the way it is pronounced is called "mickra"- î÷øà and is masculine. On the other side, in the pair circle-diameter, the circle represents a feminine, material notion (e.g. the mother Earth) while the straight line represents the masculine, spiritual notion (e.g. the rain that fertilizes the earth). Hence the word ÷åä (qava) is related to the circle while ÷å (qav) to the diameter. With this correspondence the verse reads "÷å (qav) ten cubits from the one brim to the other … and a ÷åä (qava) of thirty cubits did circle it round about". Thus the ratio of a circle to diameter becomes (30xqava)/(10xqav)=333/106.
Notice that that all objects in the tabernacle where straight. May be this is the reason why Rambam draw the Menorah with straight branches? If in the "heavens", in the spiritual world, there are no curved lines, the circle is perhaps represented there by a polygon. In case of the perimeter of the circle, the hexagon could serve as a model. In case of the area, the dodecagon could be the model. In the first case the perimeter is equal 2∙3∙radius of the surrounding circle; in the second case the area equals 3∙square of the radius, as if π=3. That is why the Sages considered the equality π=3 not as an acceptable approximation but as a reflection of a certain spiritual truth.
The idea that π represents the ratio of feminine to masculine
could be demonstrated by the number 135. Doubling of its digits 113355 and separation
113:355 leads to the ratio 355/113 that approximates π with seven
significant digits! The analogy is the
double faced Adam and his separation into a man and a woman. The same idea
could be traced in the volume of kaporet- the cover
of the arc. Its length was 2.5 cubits or 15 palms, the width was 1.5 cubits or
9 palms and the thickness was one palm. Thus its volume was 135 cub. palms. Two cherubim, a boy and
a girl, where growing out of it, separated by a tiny gap between their wings.
The same was the volume of the sockets under the pillars of the tabernacle
(their dimension was 4.5x6x6 palms from which one should subtract the volume of
the wooden legs of the pillars 1.5x3x6 palms). Two sockets were put on two legs
of a pillar and were united by the pillar. We encounter again the number 135 in
the plan of the
Let us discuss now the volume of the molten sea. As already
mentioned above, this volume according to Kings I was 2000 bat or 450 cub. cubits. However, the volume of the cylinder of the diameter
10 and the height 5 cubits is π52∙5=392.7 cub. cubits. If one assumes according to the Talmud Eruvin 14a that the lower three cubits of the sea were a
square of 10 by 10 and the upper two cubits were a circle with diameter 10,
then one obtains the volume 300+ π52∙2=457.08 cub. cubits. One can suggest that the Scriptures rounded down
this number to 450, or adjusted it to the approximation of π by 3. But, since a hidden deep meaning was found in
the perimeter of the sea, we will try to find such meaning also in the volume
of the sea. For that sake one should
first understand by what cubits the sea was measured. It is written in Talmud Iruvin 83a that the unit of volume "seah" (equal to 3/40 cub. cubits) increased in
After this discourse let us return to the
The volume of the sea is V=πr2h-V1=375.474696 cub. cubits of 51 cm. If we translate them into cubits of 48 cm, we obtain 450.36796 cub. cubits. It is almost the requested number. But we did not pay attention to the fixtures of the sea. The verse 7:24 reads "and under the brim of it round about there were knops (peqaim in Hebrew) compassing it, ten in a cubit, compassing the sea round about; the knops were in two rows, cast with it in the same casting" (see the view from above). Perhaps these knops were cast in the walls from inside and thus decreased the volume of the sea? The word peqaat in Hebrew means something round, apparently a ball. If ten of them were in one cubit then the diameter of each one was 1/10 cubit. Interestingly enough, the ancient Aramaic translation of Jonathan ben Uziel calls these peqaim- eggs. By definition, the volume of an egg is 1/1920 of a cub. cubit. The volume of a ball of diameter 1/10 is 4/3π(1/20)3=1/1909.86. If one approximates π by the ratio 25/8=3.125 then one obtains exactly 1/1920. How many balls were in a row? If we calculate the perimeter of the brim by the correct value of π, we obtain 314.5 balls. Most likely the number of balls was "round", 300. The perimeter of 30 cubits as stated by the verse could hint to this number of balls. There is no contradiction between this number of balls and the actual perimeter- there were small gaps between the balls. Two rows of balls – total of 600. However, since the balls were immersed partially into the thickness of the walls, we should subtract the volume of the immersed part. We will assume that the upper row of balls was sitting just below the brim and the second row right below the first one (see the side view). Then the center of the balls of the first row lies 1/20 cubit below the brim and of the second row 3/20 cubits below the brim. The thickness of the wall there is correspondingly 0.0033 and 0.0099 of a cubit. The immersed volume of the first row is equal approximately to a volume of one ball and of the second row- about 8.2 balls. High accuracy numerical integration gives respectfully 1.03 and 8.30, together 9.33 balls. Hence we should subtract from the volume of the sea 590.67 balls. With a volume of a ball 1/1909.86 cubic cubits, we obtain the volume of the sea 375.165422 cub. cubits of 51 cm or 449.99700 cub. cubits of 48 cm. If we count the ball as an egg of 1/1920 cub. cubits, we obtain the net volume of the sea 449.999 instead of 450.0. A relative error of 1/500,000! Of course, this is a theoretical accuracy since a copper vessel would expand under the pressure of water and even the water would compress under its own pressure.
Let us summarize the results of our investigation. Obviously, King Solomon knew not only the value of π with high accuracy but was also able to calculate the volume of a body of rotation with 6 digits. But we are talking here not about human wisdom but of divine wisdom. No human mind could design a vessel of such simplicity and harmony and at the same time arrive at a "round" volume with 6-digit accuracy. Also the play of words with the line ÷åä/÷å (qava/qav) which corresponds to the approximation of π by a continuous fraction, should have been built in the Hebrew language.
Our story would be incomplete if we will not bring the
reaction of critics. What do they say? The pair of words ÷å/÷åä (qava/qav)
appears in the Scriptures in two more places: in Jeremiah 31:38 and Zachariah
1:16. In both cases the text does not talk about the length of a circle and the
number π. Hence the difference between the spelling and the reading of
this word does not have the meaning we attributed to it. What can we reply? The
same word or group of words could be used in different places to code different
things. The fact that we don't understand the coding in one place does not
diminish our understanding in another place. Yet, I will suggest an
interpretation of this pair of words in the above two places. In both cases the
text talks about the future expansion of
Now let us calculate the perimeter of the strip of Messiah.
All this is remarkable, but what has it to do with the
ratio ÷å/÷åä (qava/qav)?
The strip that surrounds the future oblation of
The inevitable conclusion is that the one, who designed
this equality, had a full control of the size of the Earth and of the geography