Why is destroying things so much more fun than building them?
We can dimly appreciate the time and effort taken to build a tall brick chimney, yet when such an amazing edifice has outlived its usefulness and plans are made to demolish it, large crowds will often gather to watch the demolition. No-one sat watching the hard work and long weeks of building as the chimney grew one round of bricks at a time, yet many will come to revel in the sudden destruction as a carefully placed explosive charge brings a multitude of bricks crashing down.
Breaking down is always easier than building up – but that doesn’t mean it is always easy.
When King Nebuchadnezzar took the city of Jerusalem, his men burned down all the important buildings in the city and broke down the walls.[1] In fact, when Nehemiah arrived in Jerusalem many years later, the rubble of the walls was spread so widely that it was very hard to ride around the city.[2]
Yet that was the simple part: destroying the city.
However, when the victor plunders the vanquished, the goal is to carry away anything the victor considers valuable. Sometimes it will be the material itself that is valued, while in other cases it may be the craftsmanship that makes an item desirable. Jerusalem was filled with both types of treasure, and many of the items taken away intact were later returned when the exiles made the long journey back from Babylon to Judah. These items would have been carefully packed and taken
away as trophies rather than as precious raw materials.
The other category of objects was valued based purely on what it was made of and how useful that material was to the conqueror.
After the destruction of Jerusalem, we read:
“What was of gold the captain of the guard took away as gold, and what was of silver, as silver.”
Jeremiah 52:19
The picture is clear: a pile of golden objects heaped into a furnace and melted. Liquid gold is solidified in moulds and bright, shiny ingots are efficiently transported back home to Babylon.
Even for large volumes of precious metals, this can work well and those shiny ingots can fund the costs of running an empire.
However, sometimes the quantities are just too great.
This is how it was with the bronze from the temple in Jerusalem.
“As for the two pillars, the one sea, the twelve bronze bulls that were under the sea, and the stands, which Solomon the king had made for the house of the Lord, the bronze of all these things was beyond weight.”
Jeremiah 52:20
Originally, these objects were cast in massive moulds dug in clay ground.[3]
At the time, the process must have required enormous, carefully designed furnaces, and enough wood to fuel them. Nebuchadnezzar and his men had neither the time nor the inclination to copy this process by turning the massive objects into bronze ingots. Instead, we are told that
“…the pillars of bronze that were in the house of the Lord, and the stands and the bronze sea that were in the house of the Lord, the Chaldeans broke in pieces, and carried all the bronze to Babylon.”
Jeremiah 52:17
Simple. Just break all of these enormous objects into pieces and chuck ‘em in a truck!
But breaking up the items of bronze from the temple would not have been easy. Let’s just think about the two columns that stood near the entrance to the temple. How much did they weigh? The following calculations are simply rough estimates – I’m an engineer after all!
Jeremiah 52:21-22 tells us that the columns were 18 cubits (9 metres) high with a capital of 5 cubits (2.5 metres) at the top. The lower section was 12 cubits (6 metres) in circumference and 4 fingers (0.1 metres) thick.
The volume of metal in this cross section can be found from a few computations:
Outer circumference, C, is 12 cubits (6 metres) = π * D
Thus the outer diameter D = 6 / π = 1.9 m, so the outer radius R = 0.95 m
The thickness of the column was 4 fingers or about 0.1 metres, so the inner radius r is about 0.85 metres.
A doughnut section has an area A = π * (R2 - r2)
A = π * (0.952 - 0.852)
A = π * (0.902 - 0.723)
A = π * 0.18
A = 0.565 m2
If we assume that the capital on top had a similar volume for each metre of height, we can use the total height of 18 + 5 cubits = 23 cubits (11.5 metres).
Volume V = 11.5 * A
V = 11.5 * 0.565
V = 6.5 m3
The density of bronze is approximately 8,700 kg/m3.
Thus, the total mass of bronze in each column is about 8,700 * 6.5 = 56,600 kilograms or almost 57 tonnes. However, if the capitals were more substantial items, given the networks and pomegranates that decorated them, they may well have weighed more than a comparable length of the column. The total weight for column and capital was probably closer to 60 tonnes.
These two columns stood vertically, but it wouldn’t have been possible to transport them to Babylon like that. Instead, the Chaldeans would have had to tip them over.
To tip over a column, you need to pull hard enough to generate a twisting force (torque) that can lift up the far side of the column until the centre of gravity goes beyond the support point nearest to you. Once you do that, you will just have to make sure that you are safely out of the way as the column crashes to the ground. So how much torque do you need? Could they have just pulled the columns over with ropes?
Well, the mass of a standing column acts through the centre of the column, while we are trying to make the column tip over the edge nearest to us, a point on the radius of the column (which is almost 1 metre).
Our rope, however, is pulling at the top of the column, which is about 11.5 metres tall (including the capital), so we enjoy a mechanical advantage that is the ratio of the height over the radius of the column, or in this case, about 11.5 to 1 (as long as we can pull the rope roughly horizontally).
To topple our 2 metre diameter and 11.5 metre tall column weighing 60,000 kilograms, we would need to apply about 60,000 / 11.5 or 5,200 kg to the rope. Is this possible?
Let’s think about it.
Natural ropes have a much lower breaking strain than the synthetic ropes we use now.
Even so, a 38 mm (1 1/2”) diameter manila rope (made using the fibres from the abaca plant found in the Philippines, which is stronger than any other natural rope material known) has a minimum breaking strain of 6,250kg (see
Phoenix Rope and Cordage: Manila Rope). Thus, one 38 mm (1 1/2”) manila rope would be sufficient to tip over such a column. However, the rope would need to be pulled by about 160 men,
each one exerting 40kg of force. Positioning 160 people to pull a rope would take at least 80m of rope, and in that distance, the rope could only rise in height from about 1 metre to 1.5 metres or it would be too high for people to pull properly. From there it would need to keep rising at the same gradient until it reached the top of the column. Similar triangles suggest that the rope would have to be about 1,680 metres (5,500 feet) long to rise the 10.5 metres from 1.0 metre
to 11.5 metres at the same gradient. Based on information from the Phoenix Rope and Cordage website referred to above, such a rope would weigh 1,350 kilograms (3,000 pounds).
This is not a practical length for such a rope. In fact, modern manufacturers normally sell this rope in 183 m (600 ft) or 366 m (1,200 ft) lengths. To effectively use such a short length of rope, you would need to build a platform to hold up all of those people at the same height as the top of the column – or find some other way of tricking physics.
Using one rope to do the whole job just wouldn’t be practical. Nevertheless, they could have tried connecting 16 ropes with 10 people pulling on each one. That may have worked.
However, it seems that a better method would be to undermine each column by removing or breaking the foundation stones on one side until the column falls or a few men pulling on a few ropes can finish the job.
This doesn’t mean it would be easy: it would be necessary to excavate for one metre under the column to get to the centre since the column was almost 2 metres in diameter. To actually tip a column over, you need to tilt it enough to make its centre of gravity lean over beyond the support point. This would have required removal of the foundation on that side to a depth of about 175mm (7 inches).
Complete removal of foundation stones may have been easier, while using a few shorter ropes to help.
Yet once the columns had been tipped over – with all the effort necessary to achieve that – there was still the difficult job of breaking them up into pieces light enough to be carried back to Babylon on carts.
Even destruction is a big job sometimes!
Notes
[1] Jeremiah 52:13-14
[2] Nehemiah 2:14
[3] 1 Kings 7:46; 2 Chronicles 4:17
